MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Trends in Cell Biology' source. Tue, 07 Feb 2012 08:49:02 +0100 http://www.medworm.com/index.php?rid=5623189&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22260888%26dopt%3DAbstract Authors: Chen X, Liang H, Zhang J, Zen K, Zhang CY Abstract In multicellular organisms, cell-to-cell communication is of particular importance for the proper development and function of the organism as a whole. Intensive studies over the past three years suggesting horizontal transfer of secreted microRNAs (miRNAs) between cells point to a potentially novel role for these molecules in intercellular communication. Using a microvesicle-dependent, or RNA-binding protein-associated, active trafficking system, secreted miRNAs can be delivered into recipient cells where they function as endogenous miRNAs, simultaneously regulating multiple target genes or signaling events. In this Opinion, we summarize recent literature on the biogenesis and uptake of secreted miRNAs, propose a possible ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5623189 Tue, 17 Jan 2012 05:00:00 +0100 5623189 http://www.medworm.com/index.php?rid=5602426&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245068%26dopt%3DAbstract Authors: Acosta JC, Gil J Abstract Senescence is a stable cell cycle arrest that can be activated by oncogenic signaling and manifests with changes in cellular organization and gene expression, such as the induction of a complex secretome. Importantly, senescence limits tumor progression and determines the outcome of conventional anticancer therapies. In recent years, therapeutic approaches such as p53 reactivation, inhibition of c-MYC in addicted tumors or treatment with cyclin-dependent kinase (CDK) inhibitors have proven effective by invoking a senescence response. The possibility of using prosenescence therapies for cancer treatment has provoked considerable interest. We propose that the senescence secretome can be a source of novel targets for prosenescence therapies, as it ha... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5602426 Fri, 13 Jan 2012 05:00:00 +0100 5602426 http://www.medworm.com/index.php?rid=5602427&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245053%26dopt%3DAbstract Authors: Ziółkowska NE, Christiano R, Walther TC Abstract Plasma membrane proteins and lipids organize into lateral domains of specific composition. Domain formation is achieved by a combination of lipid-lipid and lipid-protein interactions, membrane-binding protein scaffolds and protein fences. The resulting domains function in membrane protein turnover and homeostasis, as well as in cell signaling. We review the mechanisms generating plasma membrane domains and the functional consequences of this organization, focusing on recent findings from research on the yeast model system. PMID: 22245053 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5602427 Thu, 12 Jan 2012 05:00:00 +0100 5602427 http://www.medworm.com/index.php?rid=5602428&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22240455%26dopt%3DAbstract Authors: Guizetti J, Gerlich DW Abstract The endosomal sorting complex required for transport (ESCRT)-III machinery contributes to membrane deformation and scission in cytokinesis, intraluminal vesicle formation, autophagy and virus budding. Recombinant ESCRT-III subunits polymerize in vitro into filaments, tubes, sheets or rings, and ESCRT-III-dependent filaments have been observed in cells at virus bud necks and at the cytokinetic abscission site. These observations have inspired speculation about how ESCRT-III could mediate constriction and fission of membrane necks. Based on the polymer structures observed in vitro and in vivo, we discuss models for ESCRT-III function and outline how emerging technologies could be used to test these models. PMID: 22240455 [PubMed - as suppl... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5602428 Tue, 10 Jan 2012 05:00:00 +0100 5602428 http://www.medworm.com/index.php?rid=5578534&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209517%26dopt%3DAbstract Authors: Hurd TR, Degennaro M, Lehmann R Abstract Reactive oxygen species (ROS), particularly hydrogen peroxide, and the proteins that regulate them play important roles in the migration and adhesion of cells. Stimulation of cell surface receptors with growth factors and chemoattractants generates ROS, which relay signals from the cell surface to key signaling proteins inside the cell. ROS act within cells to promote migration and also in nonmigrating cells to influence the behavior of migrating cells. Hydrogen peroxide has also been suggested to act as a chemoattractant in its own right, drawing immune cells to wounds. We discuss recent progress made towards understanding how organisms use ROS, and to what degree they depend on them, during the related processes of cell migration ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5578534 Fri, 30 Dec 2011 05:00:00 +0100 5578534 http://www.medworm.com/index.php?rid=5550432&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22196214%26dopt%3DAbstract Authors: Wray J, Hartmann C Abstract Embryonic stem cells (ESCs) - undifferentiated cells originating from preimplantation stage embryos - have prolonged self-renewal capacity and are pluripotent. Activation of the canonical Wnt pathway is implicated in maintenance of and exit from the pluripotent state. Recent findings demonstrate that the essential mediator of canonical Wnt signaling, β-catenin, is dispensable for ESC maintenance; however, its activation inhibits differentiation through derepression of T cell factor 3 (Tcf3)-bound genes. Wnt agonists are useful in deriving ESCs from recalcitrant mouse strains and the rat and in nuclear reprogramming of somatic stem cells. We discuss recent advances in our understanding of the role of canonical Wnt signaling in the regulation of ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5550432 Wed, 21 Dec 2011 05:00:00 +0100 5550432 http://www.medworm.com/index.php?rid=5550431&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22196215%26dopt%3DAbstract Authors: Weake VM, Workman JL Abstract The Spt-Ada-Gcn5-acetyltransferase (SAGA) transcription coactivator plays multiple roles in regulating transcription because of the presence of functionally independent modules of subunits within the complex. We have recently identified a role for the ubiquitin protease activity of SAGA in regulating tissue-specific gene expression in Drosophila. Here, we discuss the modular nature of SAGA and the different mechanisms through which SAGA is recruited to target promoters. We propose that the genes sensitive to loss of the ubiquitin protease activity of SAGA share functional characteristics that require deubiquitination of monoubiquitinated histone H2B (ubH2B) for full activation. We hypothesize that deubiquitination of ubH2B by SAGA destabilizes... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5550431 Wed, 21 Dec 2011 05:00:00 +0100 5550431 http://www.medworm.com/index.php?rid=5535278&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22189166%26dopt%3DAbstract Authors: Cheung ZH, Ip NY Abstract Since the identification of cyclin-dependent kinase-5 (Cdk5) as a tau kinase and member of the Cdk family almost 20 years ago, deregulation of Cdk5 activity has been linked to an array of neurodegenerative diseases. As knowledge on the etiopathological mechanisms of these diseases evolved through the years, Cdk5 has also been implicated in additional cellular events that are affected under these pathological conditions. From the role of Cdk5 in the regulation of synaptic functions to its involvement in autophagy deregulation, significant insights have been obtained regarding the role of Cdk5 as a key regulator of neurodegeneration. Here, we summarize recent findings on the involvement of Cdk5 in the pathophysiological mechanisms underlying various... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5535278 Mon, 19 Dec 2011 05:00:00 +0100 5535278 http://www.medworm.com/index.php?rid=5535279&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177962%26dopt%3DAbstract Authors: Han S, Brunet A Abstract How long organisms live is not entirely written in their genes. Recent findings reveal that epigenetic factors that regulate histone methylation, a type of chromatin modification, can affect lifespan. The reversible nature of chromatin modifications suggests that therapeutic targeting of chromatin regulators could be used to extend lifespan and healthspan. This review describes the epigenetic regulation of lifespan in diverse model organisms, focusing on the role and mode of action of chromatin regulators that affect two epigenetic marks, trimethylated lysine 4 of histone H3 (H3K4me3) and trimethylated lysine 27 of histone H3 (H3K27me3), in longevity. PMID: 22177962 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5535279 Thu, 15 Dec 2011 05:00:00 +0100 5535279 http://www.medworm.com/index.php?rid=5513791&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22154076%26dopt%3DAbstract We present here an overview of well-known p53 target genes and the tumor phenotypes of the cognate knockout mice, and address the recent identification of new p53 transcriptional targets and how they enhance our understanding of p53 transcriptional networks central for tumor suppression. PMID: 22154076 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5513791 Thu, 08 Dec 2011 05:00:00 +0100 5513791 http://www.medworm.com/index.php?rid=5513790&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22154077%26dopt%3DAbstract Authors: Starostina NG, Kipreos ET Abstract The mammalian CIP/KIP family of cyclin-dependent kinase (CDK) inhibitors (CKIs) comprises three proteins - p21(Cip1/WAF1), p27(Kip1), and p57(Kip2) - that bind and inhibit cyclin-CDK complexes, which are key regulators of the cell cycle. CIP/KIP CKIs have additional independent functions in regulating transcription, apoptosis and actin cytoskeletal dynamics. These divergent functions are performed in distinct cellular compartments and contribute to the seemingly contradictory observation that the CKIs can both suppress and promote cancer. Multiple ubiquitin ligases (E3s) direct the proteasome-mediated degradation of p21, p27 and p57. This review analyzes recent data highlighting our current understanding of how distinct E3 pathways regula... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5513790 Thu, 08 Dec 2011 05:00:00 +0100 5513790 http://www.medworm.com/index.php?rid=5513792&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22153608%26dopt%3DAbstract Authors: Varelas X, Wrana JL Abstract Genetic and biochemical studies have defined the Hippo pathway as a central mediator of developmental and pathogenic signals. By directing intracellular signaling events, the Hippo pathway fine-tunes cell proliferation, cell death, and cell-fate decisions, and coordinates these cues to specify animal organ size. Recent studies have revealed that Hippo pathway-mediated processes are interconnected with those of other key signaling cascades, such as those mediated by TGF-β and Wnt growth factors. Moreover, several reports have described a role for cell contact-mediated polarity proteins in Hippo pathway regulation. Emerging details suggest that crosstalk between these signals drives fundamental developmental processes, and deregulated intercellu... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5513792 Mon, 05 Dec 2011 05:00:00 +0100 5513792 http://www.medworm.com/index.php?rid=5513794&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130221%26dopt%3DAbstract Authors: Bechler ME, de Figueiredo P, Brown WJ Abstract The mammalian Golgi complex, trans Golgi network (TGN) and ER-Golgi intermediate compartment (ERGIC) are comprised of membrane cisternae, coated vesicles and membrane tubules, all of which contribute to membrane trafficking and maintenance of their unique architectures. Recently, a new cast of players was discovered to regulate the Golgi and ERGIC: four unrelated cytoplasmic phospholipase A (PLA) enzymes, cPLA(2)α (GIVA cPLA(2)), PAFAH Ib (GVIII PLA(2)), iPLA(2)-β (GVIA-2 iPLA(2)) and iPLA(1)γ. These ubiquitously expressed enzymes regulate membrane trafficking from specific Golgi subcompartments, although there is evidence for some functional redundancy between PAFAH Ib and cPLA(2)α. Three of these enzymes, PAFAH Ib, cPLA(... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5513794 Mon, 28 Nov 2011 05:00:00 +0100 5513794 http://www.medworm.com/index.php?rid=5513793&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22130222%26dopt%3DAbstract We present these examples as works-in-progress and highlight opportunities for future studies into both the direct consequence of force production and embryonic tissue mechanics and potential roles of signaling from biomechanical processes. PMID: 22130222 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5513793 Mon, 28 Nov 2011 05:00:00 +0100 5513793 http://www.medworm.com/index.php?rid=5456391&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119497%26dopt%3DAbstract Authors: Levayer R, Lecuit T Abstract Cells are active materials; they can change shape using internal energy to build contractile networks of actin filaments and myosin motors. Contractility of the actomyosin cortex is tightly regulated in space and time to orchestrate cell shape changes. Conserved biochemical pathways regulate actomyosin networks in subcellular domains which drive cell shape changes. Actomyosin networks display complex dynamics, such as flows and pulses, which participate in myosin distribution and provide a more realistic description of the spatial distribution and evolution of forces during morphogenesis. Such dynamics are influenced by the mechanical properties of actomyosin networks. Moreover, actomyosin can self-organize and respond to mechanical stimuli thr... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5456391 Thu, 24 Nov 2011 05:00:00 +0100 5456391 http://www.medworm.com/index.php?rid=5421451&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22055166%26dopt%3DAbstract Authors: Claessen JH, Kundrat L, Ploegh HL Abstract Protein maturation in the endoplasmic reticulum (ER) is subject to stringent quality control. Terminally misfolded polypeptides are usually ejected into the cytoplasm and targeted for destruction by the proteasome. Ubiquitin conjugation is essential for both extraction and proteolysis. We discuss the role of the ubiquitin conjugation machinery in this pathway and focus on the role of ubiquitin ligase complexes as gatekeepers for membrane passage. We then examine the type of ubiquitin modification applied to the misfolded ER protein and the role of de-ubiquitylating enzymes in the extraction of proteins from the ER. PMID: 22055166 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5421451 Thu, 03 Nov 2011 04:00:00 +0100 5421451 http://www.medworm.com/index.php?rid=5380045&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22047760%26dopt%3DAbstract Authors: Fischer RS, Wu Y, Kanchanawong P, Shroff H, Waterman CM Abstract The power of fluorescence microscopy to study cellular structures and macromolecular complexes spans a wide range of size scales, from studies of cell behavior and function in physiological 3D environments to understanding the molecular architecture of organelles. At each length scale, the challenge in 3D imaging is to extract the most spatial and temporal resolution possible while limiting photodamage/bleaching to living cells. Several advances in 3D fluorescence microscopy now offer higher resolution, improved speed, and reduced photobleaching relative to traditional point-scanning microscopy methods. We discuss a few specific microscopy modalities that we believe will be particularly advantageous in imagin... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380045 Mon, 31 Oct 2011 04:00:00 +0100 5380045 http://www.medworm.com/index.php?rid=5380047&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22036197%26dopt%3DAbstract Authors: Mogilner A, Odde D Abstract Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated we must address the issue of modeling cellular processes in 3D. Here, we highlight recent advances related to 3D modeling in cell biology. While some processes require full 3D analysis, we suggest that others are more naturally described in 2D or 1D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test f... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380047 Thu, 27 Oct 2011 04:00:00 +0100 5380047 http://www.medworm.com/index.php?rid=5380046&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22036198%26dopt%3DAbstract Authors: Wolf K, Friedl P Abstract Cell invasion into the 3D extracellular matrix (ECM) is a multistep biophysical process involved in inflammation, tissue repair, and metastatic cancer invasion. Migrating cells navigate through tissue structures of complex and often varying physicochemical properties, including molecular composition, porosity, alignment and stiffness, by adopting strategies that involve deformation of the cell and engagement of matrix-degrading proteases. We review how the ECM determines whether or not pericellular proteolysis is required for cell migration, ranging from protease-driven invasion and secondary tissue destruction, to non-proteolytic, non-destructive movement that solely depends on cell deformability and available tissue space. These concepts call fo... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380046 Thu, 27 Oct 2011 04:00:00 +0100 5380046 http://www.medworm.com/index.php?rid=5380048&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22033488%26dopt%3DAbstract Authors: Huh D, Hamilton GA, Ingber DE Abstract 3D cell-culture models have recently garnered great attention because they often promote levels of cell differentiation and tissue organization not possible in conventional 2D culture systems. We review new advances in 3D culture that leverage microfabrication technologies from the microchip industry and microfluidics approaches to create cell-culture microenvironments that both support tissue differentiation and recapitulate the tissue-tissue interfaces, spatiotemporal chemical gradients, and mechanical microenvironments of living organs. These 'organs-on-chips' permit the study of human physiology in an organ-specific context, enable development of novel in vitro disease models, and could potentially serve as replacements for animal... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380048 Tue, 25 Oct 2011 04:00:00 +0100 5380048 http://www.medworm.com/index.php?rid=5380049&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22030103%26dopt%3DAbstract Authors: Alvania R PMID: 22030103 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380049 Mon, 24 Oct 2011 04:00:00 +0100 5380049 http://www.medworm.com/index.php?rid=5380050&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22018597%26dopt%3DAbstract Authors: Weinberg J, Drubin DG Abstract Clathrin-mediated endocytosis in the budding yeast Saccharomyces cerevisiae involves the ordered recruitment, activity and disassembly of nearly 60 proteins at distinct sites on the plasma membrane. Two-color live-cell fluorescence microscopy has proven to be invaluable for in vivo analysis of endocytic proteins: identifying new components, determining the order of protein arrival and dissociation, and revealing even very subtle mutant phenotypes. Yeast genetics and functional genomics facilitate identification of complex interaction networks between endocytic proteins and their regulators. Quantitative datasets produced by these various analyses have made theoretical modeling possible. Here, we discuss recent findings on budding yeast endocy... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5380050 Thu, 20 Oct 2011 04:00:00 +0100 5380050 http://www.medworm.com/index.php?rid=5345908&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22014899%26dopt%3DAbstract Authors: Radhakrishnan SK, Viollier P Abstract Developmental events are executed with delicate precision and are strictly in tune with one another. Whereas synchronization is generally attained at the transcriptional level via DNA-binding proteins that regulate multiple genetic modules, numerous recent studies using bacterial model systems reveal that bifunctional proteins are often appropriated as molecular couplers that act at the post-translational level. Here, we detail the developmental events that underlie such coupling and recap the molecular mechanisms by which coupling is achieved. PMID: 22014899 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5345908 Tue, 18 Oct 2011 04:00:00 +0100 5345908 http://www.medworm.com/index.php?rid=5345909&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22001186%26dopt%3DAbstract Authors: Maceyka M, Harikumar KB, Milstien S, Spiegel S Abstract The bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P) is now recognized as a critical regulator of many physiological and pathophysiological processes, including cancer, atherosclerosis, diabetes and osteoporosis. S1P is produced in cells by two sphingosine kinase isoenzymes, SphK1 and SphK2. Many cells secrete S1P, which can then act in an autocrine or paracrine manner. Most of the known actions of S1P are mediated by a family of five specific G protein-coupled receptors. More recently, it was shown that S1P also has important intracellular targets involved in inflammation, cancer and Alzheimer's disease. This suggests that S1P actions are much more complex than previously thought, with important ramifi... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5345909 Fri, 14 Oct 2011 04:00:00 +0100 5345909 http://www.medworm.com/index.php?rid=5345911&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978761%26dopt%3DAbstract Authors: Weinlich R, Dillon CP, Green DR Abstract An old puzzle in the field of cell death was solved recently: the mysterious embryonic lethality of animals deficient in caspase-8 or Fas-associated death domain (FADD), proteins involved in a pathway of apoptosis. This lethality is caused by a failure to develop the yolk sac vasculature rather than a lack of apoptosis. Remarkably, development is rescued by ablation of either of two receptor interacting serine-threonine kinases (RIPKs). Despite being well known cell killers, caspase-8 and FADD act together to block RIPK-mediated necrosis. To manifest this newly elucidated pro-survival function, FADD and caspase-8 depend on FLIP(Long), a catalytically inactive caspase-8 homolog. In this review, the mechanism by which RIPK necrotic de... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5345911 Tue, 04 Oct 2011 04:00:00 +0100 5345911 http://www.medworm.com/index.php?rid=5345910&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978762%26dopt%3DAbstract Authors: Wickliffe KE, Williamson A, Meyer HJ, Kelly A, Rape M Abstract Modification of proteins with ubiquitin chains is an essential regulatory event in cell cycle control. Differences in the connectivity of ubiquitin chains are believed to result in distinct functional consequences for the modified proteins. Among eight possible homogenous chain types, canonical Lys48-linked ubiquitin chains have long been recognized to drive the proteasomal degradation of cell cycle regulators, and Lys48 is the only essential lysine residue of ubiquitin in yeast. It thus came as a surprise that in higher eukaryotes atypical K11-linked ubiquitin chains regulate the substrates of the anaphase-promoting complex and control progression through mitosis. We discuss recent findings that shed light on ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5345910 Tue, 04 Oct 2011 04:00:00 +0100 5345910 http://www.medworm.com/index.php?rid=5281368&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21955996%26dopt%3DAbstract Authors: Piper RC, Lehner PJ Abstract Cell survival, growth, differentiation and homeostasis rely on exquisite control of the abundance of particular cell-surface membrane proteins. Cell-surface proteins must respond appropriately to environmental and intracellular cues, often undergoing regulated internalization and lysosomal degradation. These proteins also can sustain damage and must be recognized and removed. A unifying mechanism has emerged for the trafficking of damaged and downregulated proteins to the lysosome by their attachment to ubiquitin (Ub), which serves as a sorting signal for clathrin-mediated internalization and sorting into late endosomes. Major questions remain as to how this system is governed, how it is adapted for different proteins, and whether Ub serves as ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5281368 Mon, 26 Sep 2011 04:00:00 +0100 5281368 http://www.medworm.com/index.php?rid=5247291&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21930382%26dopt%3DAbstract Authors: Panbianco C, Gotta M Abstract Decisions of when and where to divide are crucial for cell survival and fate, and for tissue organization and homeostasis. The temporal coordination of mitotic events during cell division is essential to ensure that each daughter cell receives one copy of the genome. The spatial coordination of these events is also crucial because the cytokinetic furrow must be aligned with the axis of chromosome segregation and, in asymmetrically dividing cells, the polarity axis. Several recent papers describe how cell shape and polarity are coordinated with cell division in single cells and tissues and begin to unravel the underlying molecular mechanisms, revealing common principles and molecular players. Here, we discuss how cells regulate the spatial and ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5247291 Sat, 17 Sep 2011 04:00:00 +0100 5247291 http://www.medworm.com/index.php?rid=5247292&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21924908%26dopt%3DAbstract Authors: Guilluy C, Garcia-Mata R, Burridge K Abstract Many fundamental processes in cell biology are regulated by Rho GTPases, including cell adhesion, migration and differentiation. While regulating cellular functions, members of the Rho protein family cooperate or antagonize each other. The resulting molecular network exhibits many levels of interaction dynamically regulated in time and space. In the first part of this review we describe the main mechanisms of this crosstalk, which can occur at three different levels of the pathway: (i) through regulation of activity, (ii) through regulation of protein expression and stability, and (iii) through regulation of downstream signaling pathways. In the second part we illustrate the importance of Rho protein crosstalk with two examples... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5247292 Thu, 15 Sep 2011 04:00:00 +0100 5247292 http://www.medworm.com/index.php?rid=5231591&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920754%26dopt%3DAbstract Authors: Mao Y Abstract The mammalian diaphanous-related (mDia) formin proteins are well known for their actin-nucleation and filament-elongation activities in mediating actin dynamics. They also directly bind to microtubules and regulate microtubule stabilization at the leading edge of the cell during cell migration. Recently, the formin mDia3 was shown to associate with the kinetochore and to contribute to metaphase chromosome alignment, a process in which kinetochores form stable attachments with growing and shrinking microtubules. We suggest that the formin mDia3 could contribute to the regulation of kinetochore-bound microtubule dynamics, in coordination with attachment via its own microtubule-binding activity, as well as via its interaction with the tip-tracker EB1 (end-bindi... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5231591 Tue, 13 Sep 2011 04:00:00 +0100 5231591 http://www.medworm.com/index.php?rid=5219226&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907582%26dopt%3DAbstract Authors: Chen L, Chisholm AD Abstract Understanding the mechanisms of axon regeneration is of great importance to the development of therapeutic treatments for spinal cord injury or stroke. Axon regeneration has long been studied in diverse vertebrate and invertebrate models, but until recently had not been analyzed in the genetically tractable model organism Caenorhabditis elegans. The small size, simple neuroanatomy, and transparency of C. elegans allows single fluorescently labeled axons to be severed in live animals using laser microsurgery. Many neurons in C. elegans are capable of regenerative regrowth, and can in some cases re-establish functional connections. Large-scale genetic screens have begun to elucidate the genetic basis of axon regrowth. PMID: 21907582 [PubMed -... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5219226 Thu, 08 Sep 2011 04:00:00 +0100 5219226 http://www.medworm.com/index.php?rid=5219228&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21900009%26dopt%3DAbstract Authors: Friedman JR, Voeltz GK Abstract The endoplasmic reticulum (ER) is a large, singular, membrane-bound organelle that has an elaborate 3D structure with a diversity of structural domains. It contains regions that are flat and cisternal, ones that are highly curved and tubular, and others adapted to form contacts with nearly every other organelle and with the plasma membrane. The 3D structure of the ER is determined by both integral ER membrane proteins and by interactions with the cytoskeleton. In this review, we describe some of the factors that are known to regulate ER structure and discuss how this structural organization and the dynamic nature of the ER membrane network allow it to perform its many different functions. PMID: 21900009 [PubMed - as supplied by publisher... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5219228 Mon, 05 Sep 2011 04:00:00 +0100 5219228 http://www.medworm.com/index.php?rid=5219227&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21900010%26dopt%3DAbstract Authors: Meldi L, Brickner JH Abstract The nucleus is a spatially organized compartment. The most obvious way in which this is achieved is at the level of chromosomes. The positioning of chromosomes with respect to nuclear landmarks and with respect to each other is both non-random and cell-type specific. This suggests that cells possess molecular mechanisms to influence the folding and disposition of chromosomes within the nucleus. The localization of many proteins is also heterogeneous within the nucleus. Therefore, chromosome folding and the localization of proteins leads to a model in which individual genes are positioned in distinct protein environments that can affect their transcriptional state. We focus here on the spatial organization of the nucleus and how it impacts upon... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5219227 Mon, 05 Sep 2011 04:00:00 +0100 5219227 http://www.medworm.com/index.php?rid=5219229&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21889892%26dopt%3DAbstract Authors: Juhas M, Eberl L, Glass JI Abstract Essential genes are absolutely required for cell survival. Determination of the universal minimal set of genes needed to sustain life is, therefore, expected to contribute greatly to our understanding of life at its simplest level, with applications in medicine and synthetic biology. The search for the minimal genome has led to the identification of often variable gene sets. We argue here that, based on the outcome of these analyses, it is becoming increasingly evident that some genes, and the functions encoded by them, are absolutely necessary for the survival of any living entity, whereas others can be omitted. We also examine ways of determining the minimal genome and discuss possible practical applications of a minimal cell. PMID... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5219229 Thu, 01 Sep 2011 04:00:00 +0100 5219229 http://www.medworm.com/index.php?rid=5157498&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21852137%26dopt%3DAbstract Authors: Chen M, Chory J Abstract As they emerge from the ground, seedlings adopt a photosynthetic lifestyle, which is accompanied by dramatic changes in morphology and global alterations in gene expression that optimizes the plant body plan for light capture. Phytochromes are red and far-red photoreceptors that play a major role during photomorphogenesis, a complex developmental program that seedlings initiate when they first encounter light. The earliest phytochrome signaling events after excitation by red light include their rapid translocation from the cytoplasm to subnuclear bodies (photobodies) that contain other proteins involved in photomorphogenesis, including a number of transcription factors and E3 ligases. In the light, phytochromes and negatively acting transcriptional... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5157498 Mon, 15 Aug 2011 23:00:00 +0100 5157498 http://www.medworm.com/index.php?rid=5141598&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21840719%26dopt%3DAbstract Authors: Grabrucker AM, Schmeisser MJ, Schoen M, Boeckers TM Abstract Intact synaptic homeostasis is a fundamental prerequisite for a healthy brain. Thus, it is not surprising that altered synaptic morphology and function are involved in the molecular pathogenesis of so-called synaptopathies including autism, schizophrenia (SCZ) and Alzheimer's disease (AD). Intriguingly, various recent studies revealed a crucial role of postsynaptic ProSAP/Shank scaffold proteins in all of the aforementioned disorders. Considering these findings, we follow the hypothesis that ProSAP/Shank proteins are key regulators of synaptic development and plasticity with clear-cut isoform-specific roles. We thus propose a model where ProSAP/Shank proteins are in the center of a postsynaptic signaling pathway ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5141598 Thu, 11 Aug 2011 23:00:00 +0100 5141598 http://www.medworm.com/index.php?rid=5141599&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21824781%26dopt%3DAbstract Taking a "good" look at free radicals in the aging process. Trends Cell Biol. 2011 Aug 6; Authors: Hekimi S, Lapointe J, Wen Y Abstract The mitochondrial free radical theory of aging (MFRTA) proposes that aging is caused by damage to macromolecules by mitochondrial reactive oxygen species (ROS). This is based on the observed association of the rate of aging and the aged phenotype with the generation of ROS and oxidative damage. However, recent findings, in particular in Caenorhabditis elegans but also in rodents, suggest that ROS generation is not the primary or initial cause of aging. Here, we propose that ROS are tightly associated with aging because they play a role in mediating a stress response to age-dependent damage. This could generate the observed correlation betwe... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5141599 Fri, 05 Aug 2011 23:00:00 +0100 5141599 http://www.medworm.com/index.php?rid=5141600&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21820312%26dopt%3DAbstract Authors: Gloerich M, Bos JL Abstract Signaling by the small G-protein Rap is under tight regulation by its GEFs and GAPs. These are multi-domain proteins that are themselves controlled by distinct upstream pathways, and thus couple different extra- and intracellular cues to Rap. The individual RapGEFs and RapGAPs are, in addition, targeted to specific cellular locations by numerous anchoring mechanisms and, consequently, may control different pools of Rap. Here, we review the various activating signals and targeting mechanisms of these proteins and discuss their contribution to the spatiotemporal regulation and biological functions of the Rap proteins. PMID: 21820312 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5141600 Tue, 02 Aug 2011 23:00:00 +0100 5141600 http://www.medworm.com/index.php?rid=5103952&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784638%26dopt%3DAbstract Authors: Trepat X, Fredberg JJ For a monolayer sheet to migrate cohesively, it has long been suspected that each constituent cell must exert physical forces not only upon its extracellular matrix but also upon neighboring cells. The first comprehensive maps of these distinct force components reveal an unexpected physical picture. Rather than showing smooth and systematic variation within the monolayer, the distribution of physical forces is dominated by heterogeneity, both in space and in time, which emerges spontaneously, propagates over great distances, and cooperates over the span of many cell bodies. To explain the severe ruggedness of this force landscape and its role in collective cell guidance, the well known mechanisms of chemotaxis, durotaxis, haptotaxis are clearly insufficie... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5103952 Thu, 21 Jul 2011 23:00:00 +0100 5103952 http://www.medworm.com/index.php?rid=5103954&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782439%26dopt%3DAbstract Authors: Al-Bassam J, Chang F The molecular mechanisms by which microtubule-associated proteins (MAPs) regulate the dynamic properties of microtubules (MTs) are still poorly understood. We review recent advances in our understanding of two conserved families of MAPs, the XMAP215/Dis1 and CLASP family of proteins. In vivo and in vitro studies show that XMAP215 proteins act as microtubule polymerases at MT plus ends to accelerate MT assembly, and CLASP proteins promote MT rescue and suppress MT catastrophe events. These are structurally related proteins that use conserved TOG domains to recruit tubulin dimers to MTs. We discuss models for how these proteins might use these individual tubulin dimers to regulate dynamic behavior of MT plus ends. PMID: 21782439 [PubMed - as supplied by ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5103954 Tue, 19 Jul 2011 23:00:00 +0100 5103954 http://www.medworm.com/index.php?rid=5103953&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21782440%26dopt%3DAbstract Authors: McCaffrey LM, Macara IG Epithelial cells comprise the foundation for the majority of organs in the mammalian body, and are the source of approximately 90% of all human cancers. Characteristically, epithelial cells form intercellular adhesions, exhibit apical/basal polarity, and orient their mitotic spindles in the plane of the epithelial sheet. Defects in these attributes result in the tissue disorganization associated with cancer. Epithelia undergo self-renewal from stem cells, which might in some cases be the cell of origin for cancers. The PAR polarity proteins are master regulators of epithelial organization, and are closely linked to signaling pathways such as Hippo, which orchestrate proliferation and apoptosis to control organ size. 3-D ex vivo culture systems can now f... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5103953 Tue, 19 Jul 2011 23:00:00 +0100 5103953 http://www.medworm.com/index.php?rid=5058043&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21764313%26dopt%3DAbstract Authors: Santiago-Tirado FH, Bretscher A Cell polarity in eukaryotes requires constant sorting, packaging and transport of membrane-bound cargo within the cell. These processes occur in two sorting hubs: the recycling endosome for incoming material and the trans-Golgi network for outgoing material. Phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate are enriched at the endocytic and exocytic sorting hubs, respectively, where they act together with small GTPases to recruit factors to segregate cargo and regulate carrier formation and transport. In this review, we summarize the current understanding of how these lipids and GTPases regulate membrane trafficking directly, emphasizing the recent discoveries of phosphatidylinositol 4-phosphate functions at the trans-Golgi n... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5058043 Thu, 14 Jul 2011 23:00:00 +0100 5058043 http://www.medworm.com/index.php?rid=5058046&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21763137%26dopt%3DAbstract Authors: Aggarwal S, Yurlova L, Simons M The wrapping of multiple layers of myelin membrane sheets around an axon is of fundamental importance for the function of the nervous system. In the central nervous system (CNS) oligodendrocytes synthesize tremendous amounts of cellular membrane to form multiple myelin internodes of highly stable membranes with a specific set of tightly packed lipids and proteins. In recent years, mouse mutants have allowed great advances in our understanding of the functional and structural role of many of the major components of myelin. The challenge now is to extend this knowledge to unravel the molecular machinery and mechanisms required to synthesize, assemble and wrap myelin multiple times around an axon at the appropriate developmental time. Such insight ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5058046 Wed, 13 Jul 2011 23:00:00 +0100 5058046 http://www.medworm.com/index.php?rid=5058045&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21763138%26dopt%3DAbstract Authors: Cuylen S, Haering CH The correct segregation of eukaryotic genomes requires the resolution of sister DNA molecules and their movement into opposite halves of the cell before cell division. The dynamic changes chromosomes need to undergo during these events depend on the action of a multi-subunit SMC (structural maintenance of chromosomes) protein complex named condensin, but its molecular function in chromosome segregation is still poorly understood. Recent studies suggest that condensin has a role in the removal of sister chromatid cohesin, in sister chromatid decatenation by topoisomerases, and in the structural reconfiguration of mitotic chromosomes. In this review we discuss possible mechanisms that could explain the variety of condensin actions during chromosome segregati... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5058045 Tue, 12 Jul 2011 23:00:00 +0100 5058045 http://www.medworm.com/index.php?rid=5058044&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21763139%26dopt%3DAbstract Authors: Gomez GA, McLachlan RW, Yap AS Cell-cell contacts are major determinants of tissue organization in both health and disease. Adhesive interactions, especially those mediated by classical cadherin receptors, influence cell-cell recognition and tissue patterning during development. Conversely, cadherin dysfunction promotes tumor progression to invasion and metastasis. Over the past three decades, we have learnt a great deal about the molecular mechanisms responsible for cadherin-based cell-cell interactions. Yet our knowledge remains incomplete. The intersection between cell biology and mechanical forces has long been suspected to be an important missing factor in understanding cadherin biology. However, tangible evidence remained elusive until recently, when several reports bega... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5058044 Tue, 12 Jul 2011 23:00:00 +0100 5058044 http://www.medworm.com/index.php?rid=5058047&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21741840%26dopt%3DAbstract Discussion of the biological significance of histone ADP-ribosylation has often been restricted to functions of the modifying enzymes, rather than to histones as ADP-ribose acceptors. In particular, the identification of specific lysine residues as ADP-ribose acceptor sites in histones and the identification of ADP-ribose binding modules raise this modification to a par with acetylation, methylation or phosphorylation. We discuss here the functional aspects of histone ADP-ribosylation and its influence on DNA repair, replication and transcription. PMID: 21741840 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5058047 Wed, 06 Jul 2011 23:00:00 +0100 5058047 http://www.medworm.com/index.php?rid=5009154&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21727007%26dopt%3DAbstract Authors: Lieleg O, Ribbeck K The controlled exchange of molecules between organelles, cells, or organisms and their environment is crucial for life. Biological gels such as mucus, the extracellular matrix (ECM), and the biopolymer barrier within the nuclear pore are well suited to achieve such a selective exchange, allowing passage of particular molecules while rejecting many others. Although hydrogel-based filters are integral parts of biology, clear concepts of how their barrier function is controlled at a microscopic level are still missing. We summarize here our current understanding of how selective filtering is established by different biopolymer-based hydrogels. We ask if the modulation of microscopic particle transport in biological hydrogels is based on a generic filtering pri... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5009154 Fri, 01 Jul 2011 23:00:00 +0100 5009154 http://www.medworm.com/index.php?rid=5009155&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21705221%26dopt%3DAbstract Authors: Pereira G, Yamashita YM Cell division is generally thought to be a process that produces an exact copy of the mother cell by precisely replicating its genomic DNA, doubling organelles, and segregating them into two cells. Many cell types from bacteria to human cells divide asymmetrically, however, to generate daughter cells with distinct characteristics. Such asymmetric divisions are fundamental to the lifespan of a cell, to embryonic development, and to stem cell homeostasis. Asymmetric division requires coordination of cellular asymmetry and the cell division machinery. Accumulating evidence suggests that the basic molecular mechanisms that govern this process are conserved from yeast to humans. In this review we highlight similarities in the mechanisms of asymmetric cell di... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=5009155 Thu, 23 Jun 2011 23:00:00 +0100 5009155 http://www.medworm.com/index.php?rid=4961719&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21665472%26dopt%3DAbstract Authors: Li J, Lin F Directed cell migration plays important roles in physiological processes such as host defense, wound healing, cancer metastasis and embryogenesis. Many organisms are capable of directional migration, which can be guided by diverse cellular factors including chemical and electrical cues. Recently, microfluidic devices that consist of small channels with micrometer dimensions are being developed for cell migration studies. These devices can precisely configure and flexibly manipulate chemical concentration gradients and electric fields, and thus can be used to study the complex guiding mechanisms for cell migration. In this paper we highlight recent applications of microfluidic devices for cell migration research, with a focus on electric field-directed cell migratio... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4961719 Fri, 10 Jun 2011 23:00:00 +0100 4961719 http://www.medworm.com/index.php?rid=4961721&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21664133%26dopt%3DAbstract Authors: Manning AL, Dyson NJ The product of the retinoblastoma tumor-susceptibility gene (RB1) is a key regulator of cell proliferation and this function is thought to be central to its tumor suppressive activity. Several studies have demonstrated that inactivation of pRB not only allows inappropriate proliferation but also undermines mitotic fidelity, leading to genome instability and ploidy changes. Such properties promote tumor evolution and correlate with increased resistance to therapeutics and tumor relapse. These observations suggest that inactivation of pRB could contribute to both tumor initiation and progression. Further characterization of the role of pRB in chromosome segregation will provide insight into processes that are misregulated in human tumors and could reveal new... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4961721 Tue, 07 Jun 2011 23:00:00 +0100 4961721 http://www.medworm.com/index.php?rid=4961720&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21664134%26dopt%3DAbstract Authors: Müller DJ, Dufrêne YF Atomic force microscopy (AFM) techniques provide a versatile platform for imaging and manipulating living cells to single-molecule resolution, thereby enabling us to address pertinent questions in key areas of cell biology, including cell adhesion and signalling, embryonic and tissue development, cell division and shape, and microbial pathogenesis. In this review, we describe the principles of AFM, and survey recent breakthroughs made in AFM-based cell nanoscopy, showing how the technology has increased our molecular understanding of the organization, mechanics, interactions and processes of the cell surface. We also discuss the advantages and limitations of AFM techniques, and the challenges remaining to be addressed in future research. PMID: 21664... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4961720 Tue, 07 Jun 2011 23:00:00 +0100 4961720 http://www.medworm.com/index.php?rid=4912734&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21632254%26dopt%3DAbstract Authors: Chan KT, Creed SJ, Bear JE Coronins are a conserved family of actin cytoskeleton regulators that promote cell motility and modulate other actin-dependent processes. Although these proteins have been known for 20 years, substantial progress has been made in the past 5 years towards their understanding. In this review, we examine this progress, place it into the context of what was already known, and pose several questions that remain to be addressed. In particular, we cover the emerging consensus about the role of Type I coronins in coordinating the function of Arp2/3 complex and ADF/cofilin proteins. This coordination plays an important role in leading-edge actin dynamics and overall cell motility. Finally, we discuss the roles played by the more exotic coronins of the Type II... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4912734 Mon, 30 May 2011 23:00:00 +0100 4912734 http://www.medworm.com/index.php?rid=4865967&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21601459%26dopt%3DAbstract Authors: Rinn JL, Huarte M p53 is possibly the most central tumor suppressor gene of our cells, integrating stress signals to activate a transcriptional program responsible for maintaining cellular homeostasis. Many of the downstream effects of p53 are a consequence of its activity as a transcription factor, resulting in the induction of multiple target genes. In addition to gene activation, however, gene repression is an essential part of the p53 cellular response. Despite extensive research efforts towards the elucidation of p53 functions, the molecular mechanisms and biological consequences of gene repression by p53 have not been studied extensively. We review our current knowledge of the mechanisms and biological consequences of p53 repression, with special attention to recently di... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4865967 Wed, 18 May 2011 23:00:00 +0100 4865967 http://www.medworm.com/index.php?rid=4865968&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21592797%26dopt%3DAbstract Authors: Ji P, Murata-Hori M, Lodish HF In all vertebrates, the cell nucleus becomes highly condensed and transcriptionally inactive during the final stages of red cell biogenesis. Enucleation, the process by which the nucleus is extruded by budding off from the erythroblast, is unique to mammals. Enucleation has critical physiological and evolutionary significance in that it allows an elevation of hemoglobin levels in the blood and also gives red cells their flexible biconcave shape. Recent experiments reveal that enucleation involves multiple molecular and cellular pathways that include histone deacetylation, actin polymerization, cytokinesis, cell-matrix interactions, specific microRNAs and vesicle trafficking; many evolutionarily conserved proteins and genes have been recruited to ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4865968 Sun, 15 May 2011 23:00:00 +0100 4865968 http://www.medworm.com/index.php?rid=4865969&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21561772%26dopt%3DAbstract Authors: Gump JM, Thorburn A The therapeutic potential of autophagy for the treatment cancer and other diseases is beset by paradoxes stemming from the complexity of the interactions between the apoptotic and autophagic machinery. The simplest question of how autophagy acts as both a protector and executioner of cell death remains the subject of substantial controversy. Elucidating the molecular interactions between the processes will help us understand how autophagy can modulate cell death, whether autophagy is truly a cell death mechanism, and how these functions are regulated. We suggest that, despite many connections between autophagy and apoptosis, a strong causal relationship wherein one process controls the other, has not been demonstrated adequately. Knowing when and how to mod... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4865969 Sun, 08 May 2011 23:00:00 +0100 4865969 http://www.medworm.com/index.php?rid=4813830&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21550242%26dopt%3DAbstract Authors: Moss TJ, Daga A, McNew JA Atlastin is an integral membrane GTPase localized to the endoplasmic reticulum (ER). In vitro and in vivo analyses indicate that atlastin is a membrane fusogen capable of driving membrane fusion, suggesting a role in ER structure and maintenance. Interestingly, mutations in the human atlastin-1 gene, SPG3A, cause a form of autosomal dominant hereditary spastic paraplegia (HSP). The etiology of HSP is unclear, but two predominant forms of the disorder are caused by mutant proteins that affect ER structure, formation and maintenance in motor neurons. In this review, we describe the current knowledge about the molecular mechanism of atlastin function and its potential role in HSP. Greater understanding of the function of atlastin and associated proteins ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813830 Wed, 04 May 2011 23:00:00 +0100 4813830 http://www.medworm.com/index.php?rid=4813829&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21550243%26dopt%3DAbstract Authors: Das A, Guo W The exocyst, an octameric protein complex mediating vesicle tethering at the plasma membrane for exocytosis, is a downstream effector of the Rab proteins Rab8 and Rab11, which are key regulators of membrane trafficking from the trans-Golgi network and recycling endosome to the plasma membrane. Rab11 and Rab8 coordinate their actions via Rabin8, the guanine nucleotide exchange factor of Rab8. A cascade of protein-protein interactions involving the Rabs and the exocyst complex couples the generation of secretory vesicles at donor compartments to their docking and fusion at the plasma membrane. Here, we discuss recent work implicating Rab proteins and the exocyst in primary ciliogenesis and epithelial lumenogenesis. In addition, we discuss early work in the budding y... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813829 Wed, 04 May 2011 23:00:00 +0100 4813829 http://www.medworm.com/index.php?rid=4813828&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21550244%26dopt%3DAbstract Authors: Wapinski O, Chang HY A new class of transcripts, long noncoding RNAs (lncRNAs), has been recently found to be pervasively transcribed in the genome. Multiple lines of evidence increasingly link mutations and dysregulations of lncRNAs to diverse human diseases. Alterations in the primary structure, secondary structure, and expression levels of lncRNAs as well as their cognate RNA-binding proteins underlie diseases ranging from neurodegeneration to cancer. Recent progress suggests that the involvement of lncRNAs in human diseases could be far more prevalent than previously appreciated. We review the evidence linking lncRNAs to diverse human diseases and highlight fundamental concepts in lncRNA biology that still need to be clarified to provide a robust framework for lncRNA genet... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813828 Wed, 04 May 2011 23:00:00 +0100 4813828 http://www.medworm.com/index.php?rid=4813838&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21444207%26dopt%3DAbstract Authors: Ohgushi M, Sasai Y Two kinds of human pluripotent cells, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), promise new avenues for medical innovation. These human cells share many similarities with mouse counterparts, including pluripotency, and they exhibit several unique properties. This review examines the diversity of mammalian pluripotent cells from a perspective of metastable pluripotency states. An intriguing phenomenon unique to human pluripotent stem cells is dissociation-induced apoptosis, which has been a technical problem for various cellular manipulations. The discovery that this apoptosis is suppressed by ROCK inhibitors brought revolutionary change to this troublesome situation. We discuss possible links of the metastable plur... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813838 Sat, 30 Apr 2011 23:00:00 +0100 4813838 http://www.medworm.com/index.php?rid=4813837&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21474317%26dopt%3DAbstract Authors: Hinkson IV, Elias JE The continual destruction and renewal of proteins that maintain cellular homeostasis has been rigorously studied since the late 1930s. Experimental techniques for measuring protein turnover have evolved to measure the dynamic regulation of key proteins and now, entire proteomes. In the past decade, the proteomics field has aimed to discover how cells adjust their proteomes to execute numerous regulatory programs in response to specific cellular and environmental cues. By combining classical biochemical techniques with modern, high-throughput technologies, researchers have begun to reveal the synthesis and degradation mechanisms that shape protein turnover on a global scale. This review examines several recent developments in protein turnover research, emph... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813837 Sat, 30 Apr 2011 23:00:00 +0100 4813837 http://www.medworm.com/index.php?rid=4813831&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21531561%26dopt%3DAbstract Authors: Macqueen AJ, Hochwagen A The coordinated execution of cell cycle processes during meiosis is essential for the production of viable gametes and fertility. Coordination is particularly important during meiotic prophase, when nuclei undergo a dramatic reorganization that requires the precise choreography of chromosome movements, pairing interactions and DNA double-strand break (DSB) repair. Analysis of the underlying regulatory mechanisms has revealed crucial and widespread roles for DNA-damage checkpoint proteins, not only in cell cycle surveillance, but also in controlling many processes uniquely characteristic of meiosis. The resulting regulatory network uses checkpoint machinery to provide an integral coordinating mechanism during every meiotic division and enables cells to ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813831 Thu, 28 Apr 2011 23:00:00 +0100 4813831 http://www.medworm.com/index.php?rid=4813833&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21530265%26dopt%3DAbstract Authors: Laprise P, Tepass U Apical-basal polarity is a basic organizing principle of epithelial cells. Consequently, defects in polarity are associated with numerous human pathologies, including many forms of cancer. Recent work in Drosophila has identified novel roles for, or has greatly enhanced our understanding of, functional modules within the epithelial polarity network. A series of recent papers have highlighted the key function of the scaffolding protein Bazooka/Par3 as an early polarity landmark, and its crucial role in dynamic segregation of the apical membrane from the adherens junction. Moreover, novel polarity modules have recently been discovered; the Yurt/Coracle group supports the basolateral membrane during a defined time window of development, while a second module, ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813833 Tue, 26 Apr 2011 23:00:00 +0100 4813833 http://www.medworm.com/index.php?rid=4813832&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21530266%26dopt%3DAbstract Authors: Oesterreich FC, Bieberstein N, Neugebauer KM Most eukaryotic protein-coding transcripts contain introns, which vary in number and position along the transcript body. Intron removal through pre-mRNA splicing is tightly linked to transcription by RNA polymerase II as it translocates along each gene. Here, we review recent evidence that transcription and splicing are functionally coupled. We focus on how RNA polymerase II elongation rates impact splicing through local regulation and transcriptional pausing within genes. Emerging concepts of how splicing-related changes in elongation might be achieved are highlighted. We place the interplay between transcription and splicing in the context of chromatin where nucleosome positioning influences elongation, and histone modifications p... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813832 Tue, 26 Apr 2011 23:00:00 +0100 4813832 http://www.medworm.com/index.php?rid=4813835&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21514162%26dopt%3DAbstract Authors: Han J, Xiong J, Wang D, Fu XD Alternative splicing is a process to differentially link exon regions in a single precursor mRNA to produce two or more different mature mRNAs, a strategy frequently used by higher eukaryotic cells to increase proteome diversity and/or enable additional post-transcriptional control of gene expression. This process can take place either co-transcriptionally or post-transcriptionally. When and where RNA splicing takes place in the cell represents a central question of cell biology; co-transcriptional splicing allows functional integration of transcription and RNA processing machineries, and could allow them to modulate one another, whereas post-transcriptional splicing could facilitate coupling RNA splicing with downstream events such as RNA export ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813835 Wed, 20 Apr 2011 23:00:00 +0100 4813835 http://www.medworm.com/index.php?rid=4813834&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21514163%26dopt%3DAbstract Authors: Malhas A, Goulbourne C, Vaux DJ The nuclear envelope (NE) physically separates nucleoplasm and cytoplasm, contributes to nuclear structural integrity, controls selective bidirectional transport of ions and macromolecular cargo, regulates gene expression, and acts as a mechanotransducer and a platform for signalling. It is noteworthy however that the NE is not simply a smooth-surfaced outer boundary but is interrupted by invaginations that reach deep within the nucleoplasm and could even traverse the nucleus completely. The existence of such a complex branched network of invaginations forming a nucleoplasmic reticulum (NR) provides sites that are capable of carrying out the 'conventional' NE functions deep within the nucleus in regions that would otherwise be remote from the nu... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813834 Tue, 19 Apr 2011 23:00:00 +0100 4813834 http://www.medworm.com/index.php?rid=4813836&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21481590%26dopt%3DAbstract Authors: Gurzov EN, Eizirik DL Diabetes is a metabolic disease affecting nearly 300 million individuals worldwide. Both types of diabetes (1 and 2) are characterized by loss of functional pancreatic β-cell mass causing different degrees of insulin deficiency. The Bcl-2 family has a double-edged effect in diabetes. These proteins are crucial controllers of the mitochondrial pathway of β-cell apoptosis induced by pro-inflammatory cytokines or lipotoxicity. In parallel, some Bcl-2 members also regulate glucose metabolism and β-cell function. In this review, we describe the role of Bcl-2 proteins in β-cell homeostasis and death. We focus on how these proteins interact, their contribution to the crosstalk between endoplasmic reticulum stress and mitochondrial permeabilization, their con... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4813836 Mon, 11 Apr 2011 23:00:00 +0100 4813836 http://www.medworm.com/index.php?rid=4651116&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21440440%26dopt%3DAbstract Authors: Wickström SA, Fässler R Membrane trafficking pathways function to sort and transport cargoes to various intracellular compartments and to the plasma membrane. This allows precise spatiotemporal control of processes such as signal transduction, which in turn is crucial for complex cell functions such as cell division, migration and polarity. Recent studies identified cell-matrix adhesions as regulators of exocytosis, endocytosis and the recycling machinery, thus establishing a new layer of crosstalk between cell adhesion and signaling. This review discusses these findings and considers their implications for signaling events downstream of integrins and growth factor receptors. PMID: 21440440 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4651116 Fri, 25 Mar 2011 00:00:00 +0100 4651116 http://www.medworm.com/index.php?rid=4582696&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21392997%26dopt%3DAbstract Authors: Nakagawa S, Prasanth KV X-chromosome inactivation has long served as an experimental model system for understanding the epigenetic regulation of gene expression. Central to this phenomenon is the long, non-coding RNA Xist that is specifically expressed from the inactive X chromosome and spreads along the entire length of the chromosome in cis. Recently, two of the proteins originally identified as components of the nuclear scaffold/matrix (S/MAR-associated proteins) have been shown to control the principal features of X-chromosome inactivation; specifically, context-dependent competency and the chromosome-wide association of Xist RNA. These findings implicate the involvement of nuclear S/MAR-associated proteins in the organization of epigenetic machinery. Here, we describe a m... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4582696 Tue, 08 Mar 2011 00:00:00 +0100 4582696 http://www.medworm.com/index.php?rid=4582697&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21354798%26dopt%3DAbstract Authors: Sherman MH, Bassing CH, Teitell MA When faced with DNA double-strand breaks (DSBs), vertebrate cells activate DNA damage response (DDR) programs that preserve genome integrity and suppress malignant transformation. Three established outcomes of the DDR include transient cell cycle arrest coupled with DNA repair, apoptosis, or senescence. However, recent studies in normal and cancer precursor or stem cells suggest that a fourth potential outcome, cell differentiation, is under the influence of DDR programs. Here we review and discuss the emerging evidence that supports the linkage of signaling from DSBs to the regulation of differentiation, including some of the molecular mechanisms driving this under-appreciated DDR outcome. We also consider the physiologic and pathologic cons... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4582697 Fri, 25 Feb 2011 00:00:00 +0100 4582697 http://www.medworm.com/index.php?rid=4582698&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21353778%26dopt%3DAbstract Authors: Aboobaker AA Planarians are capable of profound regenerative feats dependent upon a population of self-renewing adult stem cells called neoblasts. The key features of neoblasts are their capacity for indefinite self-renewal, their totipotency and the ability of their progeny to interpret differentiation and polarity signals and correctly replace lost structures after tissue damage. Regeneration in planarians offers a paradigm for understanding the molecular and cellular control of the repair and regeneration of animal tissues, and could provide valuable insights for the safe use of stem cells to repair damaged, diseased and ageing human tissues with little or no regenerative capacities. Here, I review recent progress in understanding neoblasts in regeneration and the growing p... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4582698 Thu, 24 Feb 2011 00:00:00 +0100 4582698 http://www.medworm.com/index.php?rid=4530657&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21349716%26dopt%3DAbstract Authors: Bohnert KA, Gould KL Cytokinesis represents the final stage in the cell cycle, in which two daughter cells, each with their complement of the duplicated genome, physically separate. At the core of this process sits highly conserved machinery responsible for specifying the plane of division, building a contractile apparatus and ultimately cleaving cells in two. Although the 'parts list' of contributing proteins has been well described, mechanisms by which these parts are spatially and temporally regulated are only beginning to be understood. With advancements in biochemical and proteomic analyses, recent work has uncovered multiple new roles for post-translational modifications in the regulation of cytokinesis. Here, we review these latest findings and interpret our current und... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4530657 Tue, 22 Feb 2011 00:00:00 +0100 4530657 http://www.medworm.com/index.php?rid=4475764&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21306900%26dopt%3DAbstract Authors: Gregan J, Polakova S, Zhang L, Tolić-Nørrelykke IM, Cimini D Accurate chromosome segregation depends on the proper attachment of sister kinetochores to microtubules emanating from opposite spindle poles. Merotelic kinetochore orientation is an error in which a single kinetochore is attached to microtubules emanating from both spindle poles. Despite correction mechanisms, merotelically attached kinetochores can persist until anaphase, causing chromatids to lag on the mitotic spindle and hindering their timely segregation. Recent studies showing that merotelic kinetochore attachment represents a major mechanism of aneuploidy in mitotic cells and is the primary mechanism of chromosomal instability in cancer cells have underlined the importance of studying merotely. Here, we hig... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4475764 Mon, 07 Feb 2011 00:00:00 +0100 4475764 http://www.medworm.com/index.php?rid=4475761&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21306901%26dopt%3DAbstract Authors: Berwick DC, Harvey K Mutations in PARK8, encoding leucine-rich repeat kinase 2 (LRRK2), are a major cause of Parkinson's disease. We contrast data suggesting that changes in LRRK2 activity cause alterations in mitogen-activated protein kinase, translational control, tumor necrosis factor α/Fas ligand and Wnt signaling pathways with the cell biological functions of LRRK2 such as vesicle trafficking. Despite scarce in vivo data on cell signaling, involvement in diverse cell biological functions suggests a role for LRRK2 as an upstream regulator in events leading to neurodegeneration. To stimulate discussion and give direction for future research, we further suggest that despite the importance of the catalytic activity for cytotoxicity, the main cellular function of LRRK2 is lin... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4475761 Mon, 07 Feb 2011 00:00:00 +0100 4475761 http://www.medworm.com/index.php?rid=4475769&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21282087%26dopt%3DAbstract Authors: Graham TR, Burd CG Phosphatidylinositol 4-kinases (PI4Ks) regulate vesicle-mediated export from the Golgi apparatus via phosphatidylinositol 4-phosphate (PtdIns4P) binding effector proteins that control vesicle budding reactions and regulate membrane dynamics. Evidence has emerged from the characterization of Golgi PI4K effectors that vesicle budding and lipid dynamics are tightly coupled via a regulatory network that ensures that the appropriate membrane composition is established before a transport vesicle buds from the Golgi. An important hub of this network is protein kinase D, which regulates the activity of PI4K and several PtdIns4P effectors that control sphingolipid and sterol content of Golgi membranes. Other newly identified PtdIns4P effectors include Vps74/GOLPH3, a... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4475769 Tue, 01 Feb 2011 00:00:00 +0100 4475769 http://www.medworm.com/index.php?rid=4475767&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21288721%26dopt%3DAbstract Authors: Collins SR, Meyer T Human stromal interaction molecule (STIM) proteins are parts of elaborate eukaryotic Ca(2+) signaling systems that include numerous plasma membrane (PM), endoplasmic reticulum (ER), and mitochondrial Ca(2+) transporters, channels and regulators. STIM2 and STIM1 function as Ca(2+) sensors with different sensitivities for ER Ca(2+). They translocate to ER-PM junctions and open PM Orai Ca(2+) influx channels when receptor-mediated Ca(2+) release lowers ER Ca(2+) levels. The resulting increase in cytosolic Ca(2+) leads to the activation of numerous Ca(2+) effector proteins that in turn regulate differentiation, cell contraction, secretion and other cell functions. In this review, we use an evolutionary perspective to survey molecular activation mechanisms in th... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4475767 Mon, 31 Jan 2011 00:00:00 +0100 4475767 http://www.medworm.com/index.php?rid=4475771&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21277210%26dopt%3DAbstract Authors: McEwan DG, Dikic I Autophagy is a highly conserved process that allows cells, tissues and organs to survive onslaughts such as nutrient deprivation, inflammation, hypoxia and other stresses. The core component proteins that regulate autophagy are well known, and the formation of a double-membrane structure that encompasses cytosolic cargo, including protein aggregates and organelles, has been intensively studied. However, less is known about the inputs that specifically alter recruitment of these components and how post-translational modifications can influence autophagy flux, or the rate at which autophagy substrates are turned over. We propose that three types of post-translational modifications - phosphorylation, ubiquitylation and acetylation - are crucial for autophagy in... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4475771 Thu, 27 Jan 2011 00:00:00 +0100 4475771 http://www.medworm.com/index.php?rid=4411810&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21257310%26dopt%3DAbstract Authors: Gallet A A major challenge of developmental biology is to understand how cells coordinate developmental behaviors with their neighbors. To achieve this, cells often employ signaling molecules that emanate from a local source and act at a distance on target cells. The Hedgehog morphogen is an essential signaling molecule required for numerous processes during animal development. Emphasizing the importance of this molecule for both growth control and patterning, Hedgehog signaling activity is often deregulated during cancer formation and progression. The secretion and spread of Hedgehog are not passive processes, but require accessory molecules involved in Hedgehog processing, release, spread and reception. In this review, I focus on the factors that are required to control the ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4411810 Fri, 21 Jan 2011 00:00:00 +0100 4411810 http://www.medworm.com/index.php?rid=4411811&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21236679%26dopt%3DAbstract Authors: Sugimoto K, Gordon SP, Meyerowitz EM The textbooks and literature of plant biology indicate that plant cells are totipotent, and that regeneration occurs via dedifferentiation, by which the cell and its descendents recapitulate earlier stages of development. However, recent work on the generation of callus, a presumed undifferentiated or dedifferentiated and disorganized cellular mass, indicates that the cells of callus are neither, and that callus forms predominantly from a pre-existing population of stem cells. Recent work in animal regeneration, for example in salamander limbs, also indicates that previous assumptions about the extent of dedifferentiation and pluripotency in animals are in need of critical reassessment. We review here some of these data, compare plant and a... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4411811 Wed, 12 Jan 2011 00:00:00 +0100 4411811 http://www.medworm.com/index.php?rid=4411813&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21232958%26dopt%3DAbstract Authors: Mason SD, Joyce JA Proteases are important for multiple processes during malignant progression, including tumor angiogenesis, invasion and metastasis. Recent evidence reveals that tumor-promoting proteases function as part of an extensive multidirectional network of proteolytic interactions, in contrast to the unidirectional caspase cascade. These networks involve different constituents of the tumor microenvironment and key proteases, such as cathepsin B, urokinase-type plasminogen activator and several matrix metalloproteinases, occupy central nodes for amplifying proteolytic signals passing through the network. The proteolytic network interacts with other important signaling pathways in tumor biology, involving chemokines, cytokines, and kinases. Viewing these proteolytic in... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4411813 Tue, 11 Jan 2011 00:00:00 +0100 4411813 http://www.medworm.com/index.php?rid=4411812&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21232959%26dopt%3DAbstract Authors: Schymeinsky J, Sperandio M, Walzog B The transmittance of force from the actin cytoskeleton via integrins to extracellular ligands is essential for multiple aspects of leukocyte function. In addition, integrins must be efficiently linked to the cytoskeleton in order to resist external forces that act on the cell. Recently, the mammalian actin-binding protein 1 (mAbp1) was identified as a novel adaptor involved in linking adhesion molecules of the β(2) integrin family to the actin cytoskeleton, indicating that this protein might have a fundamental impact on leukocyte functions that are associated explicitly with force transmittance; namely, intraluminal adhesion and phagocytosis. Here, we review the current understanding of the molecular and cellular functions of mAbp1 with a ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4411812 Tue, 11 Jan 2011 00:00:00 +0100 4411812 http://www.medworm.com/index.php?rid=4346223&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21215635%26dopt%3DAbstract Authors: Ramírez OA, Couve A Neurons are highly polarized cells whose dendrites and axons extend long distances from the cell body to form synapses that mediate neuronal communication. The trafficking of membrane lipids and proteins throughout the neuron is essential for the establishment and maintenance of cell morphology and synaptic function. However, the dynamic shape and spatial organization of secretory organelles, and their role in defining neuronal polarity and the composition of synapses, are not well delineated. In particular, the structure and function of the continuous and intricate network of the endoplasmic reticulum (ER) in neurons remain largely unknown. Here we review our current understanding of the ER in dendrites and axons, its contribution to local trafficking of ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4346223 Wed, 05 Jan 2011 00:00:00 +0100 4346223 http://www.medworm.com/index.php?rid=4346225&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21183348%26dopt%3DAbstract Authors: Bonifacino JS, Hierro A Tethering factors are large protein complexes that capture transport vesicles and enable their fusion with acceptor organelles at different stages of the endomembrane system. Recent studies have shed new light on the structure and function of a heterotetrameric tethering factor named Golgi-associated retrograde protein (GARP), which promotes fusion of endosome-derived, retrograde transport carriers to the trans-Golgi network (TGN). X-ray crystallography of the Vps53 and Vps54 subunits of GARP has revealed that this complex is structurally related to other tethering factors such as the exocyst, the conserved oligomeric Golgi (COG) and Dsl1 (dependence on SLY1-20) complexes, indicating that they all might work by a similar mechanism. Loss of GARP function... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4346225 Tue, 21 Dec 2010 00:00:00 +0100 4346225 http://www.medworm.com/index.php?rid=4346224&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21183349%26dopt%3DAbstract Authors: Makareeva E, Aviles NA, Leikin S Recent discoveries of severe bone disorders in patients with deficiencies in several endoplasmic reticulum chaperones are reshaping the discussion of type I collagen folding and related diseases. Type I collagen is the most abundant protein in all vertebrates and a crucial structural molecule for bone and other connective tissues. Its misfolding causes bone fragility, skeletal deformity and other tissue failures. Studies of newly discovered bone disorders indicate that collagen folding, chaperones involved in the folding process, cellular responses to misfolding and related bone pathologies might not follow conventional protein folding paradigms. In this review, we examine the features that distinguish collagen folding from that of other protei... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4346224 Tue, 21 Dec 2010 00:00:00 +0100 4346224 http://www.medworm.com/index.php?rid=4346226&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21177106%26dopt%3DAbstract Authors: Oh Y, Bi E Septins are conserved GTP-binding proteins that assemble into hetero-oligomeric complexes and higher-order structures such as filaments, rings, hourglasses or gauzes. Septins are usually associated with a discrete region of the plasma membrane and function as a cell scaffold or diffusion barrier to effect cytokinesis, cell polarity, and many other functions. Recent structural studies of septin complexes have provided mechanistic insights into septin filament assembly, but key questions concerning the assembly, dynamics, and function of different septin structures remain to be answered. PMID: 21177106 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4346226 Mon, 20 Dec 2010 00:00:00 +0100 4346226 http://www.medworm.com/index.php?rid=4279255&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21145746%26dopt%3DAbstract Authors: Gill DJ, Clausen H, Bard F O-GalNAc glycosylation of proteins confers essential structural, protective and signaling roles in eumetazoans. Addition of O-glycans onto proteins is an extremely complex process that regulates both sites of attachment and the types of oligosaccharides added. Twenty distinct polypeptide GalNAc-transferases (GalNAc-Ts) initiate O-glycosylation and fine-tuning their expression provides a mechanism for regulating this action. Recently, a new mode of regulation has emerged where activation of Src kinase selectively redistributes Golgi-localized GalNAc-Ts to the ER. This relocalization results in a strong increase in the density of O-glycan decoration. In this review, we discuss how different mechanisms can regulate the number and the types of O-glycans ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4279255 Wed, 08 Dec 2010 00:00:00 +0100 4279255 http://www.medworm.com/index.php?rid=4279257&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21145238%26dopt%3DAbstract Authors: Edidin M PMID: 21145238 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4279257 Tue, 07 Dec 2010 00:00:00 +0100 4279257 http://www.medworm.com/index.php?rid=4279256&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21145239%26dopt%3DAbstract Authors: Kovar DR, Sirotkin V, Lord M How the actin cytoskeleton assembles into different structures to drive diverse cellular processes is a fundamental cell biological question. In addition to orchestrating the appropriate combination of regulators and actin-binding proteins, different actin-based structures must insulate themselves from one another to maintain specificity within a crowded cytoplasm. Actin specification is particularly challenging in complex eukaryotes where a multitude of protein isoforms and actin structures operate within the same cell. Fission yeast Schizosaccharomyces pombe possesses a single actin isoform that functions in three distinct structures throughout the cell cycle. In this review we explore recent studies in fission yeast that help unravel how differe... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4279256 Tue, 07 Dec 2010 00:00:00 +0100 4279256 http://www.medworm.com/index.php?rid=4279258&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21144752%26dopt%3DAbstract Authors: Insall RH PMID: 21144752 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4279258 Mon, 06 Dec 2010 00:00:00 +0100 4279258 http://www.medworm.com/index.php?rid=4202824&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21095561%26dopt%3DAbstract Authors: Nelson WJ, Hosking CR, Alvania R PMID: 21095561 [PubMed - in process] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4202824 Fri, 26 Nov 2010 16:25:17 +0100 4202824 http://www.medworm.com/index.php?rid=4202822&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21106464%26dopt%3DAbstract Authors: Goldstein LS Scientific research is an often misunderstood, undervalued and yet essential activity. Many nonscientists think that research is quick and easy, and that science is a compilation of established facts rather than rigorous conclusions based on available evidence. In addition, many nonscientists, and perhaps many scientists as well, forget that our social and financial investment is small relative to the massive and expensive problems that we all want scientific research to solve. Using biomedical research in the United States as an example, I will argue that countering this underinvestment in science will require broadening perspectives in the scientific community as well as coupling expanded individual advocacy and education efforts to an interdisciplinary advocacy... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4202822 Fri, 26 Nov 2010 16:25:08 +0100 4202822 http://www.medworm.com/index.php?rid=4202823&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21106376%26dopt%3DAbstract Authors: Lampson MA, Cheeseman IM Maintaining genome integrity during cell division requires regulated interactions between chromosomes and spindle microtubules. To ensure that daughter cells inherit the correct chromosomes, the sister kinetochores must attach to opposite spindle poles. Tension across the centromere stabilizes correct attachments, whereas phosphorylation of kinetochore substrates by the conserved Ipl1/Aurora B kinase selectively eliminates incorrect attachments. Here, we review our current understanding of how mechanical forces acting on the kinetochore are linked to biochemical changes to control chromosome segregation. We discuss models for tension sensing and regulation of kinetochore function downstream of Aurora B, and mechanisms that specify Aurora B localization... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4202823 Mon, 22 Nov 2010 00:00:00 +0100 4202823 http://www.medworm.com/index.php?rid=4169276&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21071226%26dopt%3DAbstract Authors: Gertler F, Condeelis J During breast cancer metastasis cells emigrate from the primary tumor to the bloodstream, and this carries them to distant sites where they infiltrate and sometimes form metastases within target organs. These cells must penetrate the dense extracellular matrix comprising the basement membrane of the mammary duct/acinus and migrate toward blood and lymphatic vessels, processes that mammary tumor cells execute primarily using epidermal growth factor (EGF)-dependent protrusive and migratory activity. Here, we focus on how the actin regulatory protein Mena affects EGF-elicited movement, invasion and metastasis. Recent findings indicate that, in invasive migratory tumor cells, Mena isoforms that endow heightened sensitivity to EGF and increased protrusive and... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4169276 Tue, 09 Nov 2010 00:00:00 +0100 4169276 http://www.medworm.com/index.php?rid=4169277&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21067929%26dopt%3DAbstract Authors: Naslavsky N, Caplan S Regulation of endocytic transport is controlled by an elaborate network of proteins. Rab GTP-binding proteins and their effectors have well-defined roles in mediating specific endocytic transport steps, but until recently less was known about the four mammalian dynamin-like C-terminal Eps15 homology domain (EHD) proteins that also regulate endocytic events. In recent years, however, great strides have been made in understanding the structure and function of these unique proteins. Indeed, a growing body of literature addresses EHD protein structure, interactions with binding partners, functions in mammalian cells, and the generation of various new model systems. Accordingly, this is now an opportune time to pause and review the function and mechanisms of a... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4169277 Mon, 08 Nov 2010 00:00:00 +0100 4169277 http://www.medworm.com/index.php?rid=4139975&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21050761%26dopt%3DAbstract Authors: Small JV PMID: 21050761 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4139975 Mon, 01 Nov 2010 00:00:00 +0100 4139975 http://www.medworm.com/index.php?rid=4139976&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21035344%26dopt%3DAbstract Authors: Volponi AA, Pang Y, Sharpe PT Teeth exhibit limited repair in response to damage, and dental pulp stem cells probably provide a source of cells to replace those damaged and to facilitate repair. Stem cells in other parts of the tooth, such as the periodontal ligament and growing roots, play more dynamic roles in tooth function and development. Dental stem cells can be obtained with ease, making them an attractive source of autologous stem cells for use in restoring vital pulp tissue removed because of infection, in regeneration of periodontal ligament lost in periodontal disease, and for generation of complete or partial tooth structures to form biological implants. As dental stem cells share properties with mesenchymal stem cells, there is also considerable interest in their ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4139976 Wed, 27 Oct 2010 00:00:00 +0100 4139976 http://www.medworm.com/index.php?rid=4108263&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20971009%26dopt%3DAbstract Authors: Higgs HN PMID: 20971009 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4108263 Wed, 20 Oct 2010 23:00:00 +0100 4108263 http://www.medworm.com/index.php?rid=4088919&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20965727%26dopt%3DAbstract Authors: Choi CK, Breckenridge MT, Chen CS Cells constantly probe and respond to a myriad of cues that are present in their local surroundings. The effects of soluble cues are relatively straightforward to manipulate, yet teasing apart how cells transduce signals from the extracellular matrix and neighboring cells has proven to be challenging due to the spatially and mechanically complex adhesive interactions. Over the years, advances in the engineering of biocompatible materials have enabled innovative ways to study adhesion-mediated cell functions, and numerous insights have elucidated the significance of the cellular microenvironment. Here, we highlight some of the major approaches and discuss the potential for future advancement. PMID: 20965727 [PubMed - as supplied by publishe... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088919 Mon, 18 Oct 2010 23:00:00 +0100 4088919 http://www.medworm.com/index.php?rid=4088922&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20961760%26dopt%3DAbstract Authors: Capasso M, Decoursey TE, Dyer MJ Electrophysiological studies have implicated voltage-gated proton channels in several specific cellular contexts. In neutrophils, they mediate charge compensation that is associated with the oxidative burst of phagocytosis. Molecular characterization of the hydrogen voltage-gated channel 1 (HVCN1) has enabled identification of unanticipated and diverse functions: HVCN1 not only modulates signaling from the B-cell receptor following B-cell activation and histamine release from basophils, but also mediates pH-dependent activation of spermatozoa, as well as acid secretion by tracheal epithelium. The importance of HVCN1 in pH regulation during phagocytosis was established by surprising evidence that indicated its first-responder role. In this revie... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088922 Sun, 17 Oct 2010 23:00:00 +0100 4088922 http://www.medworm.com/index.php?rid=4088921&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20961761%26dopt%3DAbstract Authors: Vaughan S, Dawe HR Centrioles are found in nearly all eukaryotic cells and are required for growth and maintenance of the radial array of microtubules, the mitotic spindle, and cilia and flagella. Different types of microtubule structures are often required at different places in a given cell; centrioles must move around to nucleate these varied structures. Here, we draw together recent data on diverse centriole movements to decipher common themes in how centrioles move. Par proteins establish and maintain the required cellular asymmetry. The actin cytoskeleton facilitates movement of multiple basal bodies. Microtubule forces acting on the cell cortex, and nuclear-cytoskeletal links, are important for positioning individual centrosomes, and during cell division. Knowledge of t... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088921 Sun, 17 Oct 2010 23:00:00 +0100 4088921 http://www.medworm.com/index.php?rid=4088920&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20961762%26dopt%3DAbstract Authors: Manjithaya R, Subramani S Autophagy, a cellular 'self-eating' process in eukaryotic cells, exists in both a basal and in an activated state that is induced in response to starvation. Basal and induced autophagy are associated with the packaging of cellular components, including damaged and/or redundant organelles, into double-membrane vesicles called autophagosomes, followed by autophagosome fusion with lysosomes, in which their contents are degraded and recycled. Recent results highlight a novel role for autophagy that does not involve lysosomal degradation of autophagosomal contents, but instead involves their redirection towards the extracellular delivery of an unconventionally secreted protein. Here, we discuss these findings, evaluate the strength of evidence, consider th... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088920 Sun, 17 Oct 2010 23:00:00 +0100 4088920 http://www.medworm.com/index.php?rid=4088925&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951587%26dopt%3DAbstract Authors: Asbury CL, Tien JF, Davis TN Climbing up a cliff while the rope unravels underneath your fingers does not sound like a well-planned adventure. Yet chromosomes face a similar challenge during each cell division. Their alignment and accurate segregation depends on staying attached to the assembling and disassembling tips of microtubule fibers. This coupling is mediated by kinetochores, intricate machines that attach chromosomes to an ever-changing microtubule substrate. Two models for kinetochore-microtubule coupling were proposed a quarter century ago: conformational wave and biased diffusion. These models differ in their predictions for how coupling is performed and regulated. The availability of purified kinetochore proteins has enabled biochemical and biophysical analyses of... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088925 Wed, 13 Oct 2010 23:00:00 +0100 4088925 http://www.medworm.com/index.php?rid=4088924&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951588%26dopt%3DAbstract Authors: Pappas CT, Bliss KT, Zieseniss A, Gregorio CC Nebulin, a giant, actin-binding protein, is the largest member of a family of proteins (including N-RAP, nebulette, lasp-1 and lasp-2) that are assembled in a variety of cytoskeletal structures, and expressed in different tissues. For decades, nebulin has been thought to act as a molecular ruler, specifying the precise length of actin filaments in skeletal muscle. However, emerging evidence suggests that nebulin should not be viewed as a ruler but as an actin filament stabilizer required for length maintenance. Nebulin has also been implicated recently in an array of regulatory functions independent of its role in actin filament length regulation. In this review, we discuss the current evolutionary, biochemical, and functional data... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088924 Wed, 13 Oct 2010 23:00:00 +0100 4088924 http://www.medworm.com/index.php?rid=4088923&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951589%26dopt%3DAbstract Authors: Gerlitz G, Bustin M Chromatin dynamics play a major role in regulating genetic processes. Now, accumulating data suggest that chromatin structure may also affect the mechanical properties of the nucleus and cell migration. Global chromatin organization appears to modulate the shape, the size and the stiffness of the nucleus. Directed-cell migration, which often requires nuclear reshaping to allow passage of cells through narrow openings, is dependent not only on changes in cytoskeletal elements but also on global chromatin condensation. Conceivably, during cell migration a physical link between the chromatin and the cytoskeleton facilitates coordinated structural changes in these two components. Thus, in addition to regulating genetic processes, we suggest that alterations in ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4088923 Wed, 13 Oct 2010 23:00:00 +0100 4088923 http://www.medworm.com/index.php?rid=4045682&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20888769%26dopt%3DAbstract Authors: Rottner K, Hänisch J, Campellone KG Arp2/3 complex mediates the nucleation of actin filaments in multiple subcellular processes, and is activated by nucleation-promoting factors (NPFs) from the Wiskott-Aldrich Syndrome family. In exciting new developments, this family has grown by three members: WASH, WHAMM and JMY, which extend the repertoire of dynamic membrane structures that are remodeled following Arp2/3 activation in vivo. These novel NPFs share an actin- and Arp2/3-interacting WCA module, and combine Arp2/3 activation with additional biochemical functions, including capping protein inhibition, microtubule engagement or Arp2/3-independent actin nucleation, none of which had been previously associated with canonical WCA-harboring proteins. Uncovering the physiological re... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4045682 Wed, 29 Sep 2010 23:00:00 +0100 4045682 http://www.medworm.com/index.php?rid=4045683&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20888233%26dopt%3DAbstract Authors: Jedd G Peroxisome-derived Woronin bodies of the Ascomycota phyla, and the endoplasmic reticulum (ER)-derived septal pore cap (SPC) of the Basidiomycota, are both fungal organelles that prevent cytoplasmic bleeding when multicellular hyphal filaments are wounded. Analysis of Woronin body constituent proteins suggests that these organelles evolved in part through gene duplication and co-opting of non-essential genes for new functions, indicating that new organelles can arise through typical evolutionary mechanisms. Interestingly, clades possessing the Woronin body and SPC also produce the largest and most complex multicellular fungal reproductive structures. Certain Woronin body and SPC mutants have defects in growth and development, suggesting functions beyond cellular wound he... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4045683 Tue, 28 Sep 2010 23:00:00 +0100 4045683 http://www.medworm.com/index.php?rid=4045684&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20880709%26dopt%3DAbstract Authors: Nezis IP, Sagona AP, Schink KO, Stenmark H Cytokinesis is the final step of cell division whereby the dividing cells separate physically. Failure of this process has been proposed to cause tumourigenesis. Several specific lipids are essential for cytokinesis, and recent evidence has revealed that phosphatidylinositol 3-phosphate (PtdIns3P) - a well-known regulator of endosomal trafficking, receptor signaling, nutrient sensing and autophagy - plays an evolutionarily conserved role during cytokinesis. The emerging picture is that PtdIns3P and its regulators and effectors constitute a novel regulatory mechanism for cytokinesis. Elucidating the role of PtdIns3P in cytokinesis might contribute to insight into mechanisms of tumour development and suppression. PMID: 20880709 [Pub... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4045684 Sun, 26 Sep 2010 23:00:00 +0100 4045684 http://www.medworm.com/index.php?rid=4011500&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20870407%26dopt%3DAbstract Authors: Yu H, Mouw JK, Weaver VM Cancer cells exist in a constantly evolving tissue microenvironment of diverse cell types within a proteinaceous extracellular matrix. As tumors evolve, the physical forces within this complex microenvironment change, with pleiotropic effects on both cell- and tissue-level behaviors. Recent work suggests that these biomechanical factors direct tissue development and modulate tissue homeostasis, and, when altered, crucially influence tumor evolution. In this review, we discuss the biomechanical regulation of cell and tissue homeostasis from the molecular, cellular and tissue levels, including how modifications of this physical dialogue could contribute to cancer etiology. Because of the broad impact of biomechanical factors on cell and tissue functions,... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4011500 Thu, 23 Sep 2010 23:00:00 +0100 4011500 http://www.medworm.com/index.php?rid=4011501&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20869247%26dopt%3DAbstract Authors: Salazar C, Brümmer A, Alberghina L, Höfer T Computational and experimental studies have yielded quantitative insights into the role for multisite phosphorylation, and other protein modifications, in cell function. This work has emphasized the creation of thresholds and switches for cellular decisions. To date, the dynamics of phosphorylation events have been disregarded yet could be equally relevant for cell function. Here, we discuss theoretical predictions about the kinetic functions of multisite phosphorylation in regulatory networks and how these predictions relate to experimental findings. Using DNA replication as an example, we demonstrate that multisite phosphorylations can support coherent origin firing and robustness against rereplication. We suggest that multis... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4011501 Tue, 21 Sep 2010 23:00:00 +0100 4011501 http://www.medworm.com/index.php?rid=4011502&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20864346%26dopt%3DAbstract Authors: Stuible M, Tremblay ML Receptor tyrosine kinases (RTKs) control the cellular response to a range of stimuli by binding extracellular factors and transmitting appropriate signals to intracellular sites. Protein tyrosine phosphatase 1B (PTP1B) modulates the activity of several RTKs by directly targeting the phosphorylated tyrosine residues that dictate their signaling output. Interestingly, the phenotypes of PTP1B deficiency in different contexts point to a more complex role in regulating RTK signaling. Exciting recent results indicate that the endocytic down-regulation of RTKs could be directly controlled by PTP1B. Microscopy studies have demonstrated an effect of PTP1B on post-endocytic internalization of RTKs into multivesicular bodies, and specific substrates that could infl... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4011502 Mon, 20 Sep 2010 23:00:00 +0100 4011502 http://www.medworm.com/index.php?rid=4011504&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20863703%26dopt%3DAbstract Authors: Pedersen MT, Helin K Histone modifications serve as regulatory marks that are instrumental for the control of transcription and chromatin architecture. Strict regulation of gene expression patterns is crucial during development and differentiation, where diverse cell types evolve from common predecessors. Since the first histone lysine demethylase was discovered in 2004, a number of demethylases have been identified and implicated in the control of gene expression programmes and cell fate decisions. Histone demethylases are now emerging as important players in developmental processes and have been linked to human diseases such as neurological disorders and cancer. PMID: 20863703 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4011504 Sun, 19 Sep 2010 23:00:00 +0100 4011504 http://www.medworm.com/index.php?rid=4011503&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20863704%26dopt%3DAbstract Authors: Miller KR No international research community, cell biology included, can exist without an educational community to renew and replenish it. Unfortunately, cell biology researchers frequently regard their work as independent of the process of education and see little reason to reach out to science teachers. For cell biology to continue to prosper, I argue that researchers must support education in at least three ways. First, we must view education and research as part of a single scientific community. Second, we should take advantage of new technologies to connect the research laboratory to the classroom. Finally, we must take the initiative in defending the integrity of science teaching, particularly when education is under attack for political or religious reasons. PMID: ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=4011503 Sun, 19 Sep 2010 23:00:00 +0100 4011503 http://www.medworm.com/index.php?rid=3982269&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20843692%26dopt%3DAbstract Authors: Steck TL, Lange Y Recent evidence suggests that the major pathways mediating cell cholesterol homeostasis respond to a common signal: active membrane cholesterol. Active cholesterol is the fraction that exceeds the complexing capacity of the polar bilayer lipids. Increments in plasma membrane cholesterol exceeding this threshold have an elevated chemical activity (escape tendency) and redistribute via diverse transport proteins to both circulating plasma lipoproteins and intracellular organelles. Active cholesterol thereby prompts several feedback responses. It is the substrate for its own esterification and for the synthesis of regulatory side-chain oxysterols. It also stimulates manifold pathways that down-regulate the biosynthesis, curtail the ingestion and increase the exp... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3982269 Sun, 12 Sep 2010 23:00:00 +0100 3982269 http://www.medworm.com/index.php?rid=3982271&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20833046%26dopt%3DAbstract Authors: Small JV The primary event in the movement of a migrating eukaryotic cell is the extension of cytoplasmic sheets termed lamellipodia composed of networks of actin filaments. Lamellipodia networks are thought to arise through the branching of new filaments from the sides of old filaments, producing a dendritic array. Recent studies by electron tomography have revealed the three dimensional organization of lamellipodia and show, contrary to previous evidence, that actin filaments do not form dendritic arrays in vivo. These findings signal a reconsideration of the structural basis of protrusion and about the roles of the different actin nucleating and elongating complexes involved in the process. PMID: 20833046 [PubMed - as supplied by publisher] (Source: Trends in Cell Biolo... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3982271 Wed, 08 Sep 2010 23:00:00 +0100 3982271 http://www.medworm.com/index.php?rid=3982270&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20833047%26dopt%3DAbstract Authors: Golachowska MR, Hoekstra D, van Ijzendoorn SC Recycling endosomes have taken central stage in the intracellular sorting and polarized trafficking of apical and basolateral plasma membrane components. Molecular players in the underlying mechanisms are now emerging, including small GTPases, class V myosins and adaptor proteins. In particular, defects in the expression or function of these recycling endosome-associated and endosome-regulating proteins have been implicated in cell surface polarity defects and diseases, including microvillus inclusion disease, arthrogryposis-renal dysfunction-cholestasis syndrome, and virus susceptibility. Key findings are that recycling endosomes recruit and deliver core polarity proteins to lateral cell surfaces and initiate the biogenesis of api... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3982270 Wed, 08 Sep 2010 23:00:00 +0100 3982270 http://www.medworm.com/index.php?rid=3982272&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20832316%26dopt%3DAbstract Authors: Iwasa JH In all branches of scientific inquiry, researchers build models that enable them to visualize, formulate and communicate their hypotheses to others. In cell biology, our conceptual understanding of a process is typically embodied in a model figure. These visual models should ideally represent pre-existing knowledge of molecular interactions, movement, structure and localization but, in reality, they often fall short. Cell biologists have begun to look to the use of three-dimensional animation to visualize and describe complex molecular and cellular events. In addition to aiding teaching and communication, animation is emerging as a powerful tool for providing researchers with insight into the processes that they study. Two case studies focusing on the structure/functi... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3982272 Tue, 07 Sep 2010 23:00:00 +0100 3982272 http://www.medworm.com/index.php?rid=3956181&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20817460%26dopt%3DAbstract Authors: Abedin M, King N The morphological diversity of animals, fungi, plants, and other multicellular organisms stems from the fact that each lineage acquired multicellularity independently. A prerequisite for each origin of multicellularity was the evolution of mechanisms for stable cell-cell adhesion or attachment. Recent advances in comparative genomics and phylogenetics provide critical insights into the evolutionary foundations of cell adhesion. Reconstructing the evolution of cell junction proteins in animals and their unicellular relatives exemplifies the roles of co-option and innovation. Comparative studies of volvocine algae reveal specific molecular changes that accompanied the evolution of multicellularity in Volvox. Comparisons between animals and Dictyostelium show how... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3956181 Wed, 01 Sep 2010 23:00:00 +0100 3956181 http://www.medworm.com/index.php?rid=3956180&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20817461%26dopt%3DAbstract Authors: Tanaka K, Gilroy S, Jones AM, Stacey G Extracellular adenosine-5'-triphosphate (ATP) induces a number of cellular responses in plants and animals. Some of the molecular components for purinergic signaling in animal cells appear to be lacking in plant cells, although some cellular responses are similar in both systems [e.g. increased levels of cytosolic free calcium, nitric oxide (NO), and reactive oxygen species (ROS)]. The purpose of this review is to compare and contrast purinergic signaling mechanisms in animal and plant cells. This comparison will aid our overall understanding of plant physiology and also provide details of the general fundamentals of extracellular ATP signaling in eukaryotes. PMID: 20817461 [PubMed - as supplied by publisher] (Source: Trends in Cell B... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3956180 Wed, 01 Sep 2010 23:00:00 +0100 3956180 http://www.medworm.com/index.php?rid=3934848&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20810283%26dopt%3DAbstract Authors: De Carvalho DD, You JS, Jones PA The recent discovery that a small number of defined factors are sufficient to reprogram somatic cells into pluripotent stem cells has significantly expanded our knowledge of the plasticity of the epigenome. In this review we discuss some aspects of cell fate plasticity and epigenetic alterations, with emphasis on DNA methylation during cellular reprogramming. Recent data suggest that DNA methylation is a major barrier to induced pluripotent stem (iPS) cell reprogramming. The demethylating agent 5-azacytidine can enhance the efficiency of iPS cells generation and the putative DNA demethylase protein activation-induced cytidine deaminase (AID/AICDA) can erase DNA methylation at pluripotency gene promoters, thereby allowing cellular reprogramming.... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3934848 Sun, 29 Aug 2010 23:00:00 +0100 3934848 http://www.medworm.com/index.php?rid=3916014&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20801657%26dopt%3DAbstract Authors: Garcia HG, Sanchez A, Kuhlman T, Kondev J, Phillips R The study of transcription has witnessed an explosion of quantitative effort both experimentally and theoretically. In this article we highlight some of the exciting recent experimental efforts in the study of transcription with an eye to the demands that such experiments put on theoretical models of transcription. From a modeling perspective, we focus on two broad classes of models: the so-called thermodynamic models that use statistical mechanics to reckon the level of gene expression as probabilities of promoter occupancy, and rate-equation treatments that focus on the temporal evolution of the activity of a given promoter and that make it possible to compute the distributions of messenger RNA and proteins. We consider s... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3916014 Thu, 26 Aug 2010 23:00:00 +0100 3916014 http://www.medworm.com/index.php?rid=3900966&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20724159%26dopt%3DAbstract Authors: Gibb S, Maroto M, Dale JK The vertebrate segmentation clock is a molecular oscillator that regulates the periodicity of somite formation. Three signalling pathways have been proposed to underlie the molecular mechanism of the oscillator, namely the Notch, Wnt and Fgf pathways. Characterizing the roles and hierarchy of these three pathways in the oscillator mechanism is currently the focus of intense research. Recent publications report the first identification of a molecular mechanism involved in the regulation of the pace of this oscillator. We review these and other recent findings regarding the interaction between the three pathways in the oscillator mechanism that have significantly expanded our understanding of the segmentation clock. PMID: 20724159 [PubMed - as suppl... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3900966 Mon, 16 Aug 2010 23:00:00 +0100 3900966 http://www.medworm.com/index.php?rid=3900965&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20724160%26dopt%3DAbstract Authors: Salomoni P, Calegari F PMID: 20724160 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3900965 Mon, 16 Aug 2010 23:00:00 +0100 3900965 http://www.medworm.com/index.php?rid=3885755&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20719512%26dopt%3DAbstract Authors: Lenos MG, Tsaniklidou SM PMID: 20719512 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3885755 Sun, 15 Aug 2010 23:00:00 +0100 3885755 http://www.medworm.com/index.php?rid=3855641&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20685121%26dopt%3DAbstract Authors: Armstrong J Thanks to their amenability to both genetic and biochemical analysis, vacuoles of S. cerevisiae are valuable models for trafficking processes to mammalian lysosomes. They also have additional functions to lysosomes, and all of these processes can influence the size and number of vacuoles. Several recent papers have indicated that some vacuolar proteins participate in more than one process, and hence could be regulatory points to balance the processes and control vacuole dimensions. Studies of vacuoles from other yeasts and fungi are uncovering further roles for vacuoles, increasing the apparent requirement for such regulation. Having served as models in the past, yeast vacuoles are now well suited to develop the next generation of quantitative methods to understand... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3855641 Sun, 01 Aug 2010 23:00:00 +0100 3855641 http://www.medworm.com/index.php?rid=3855640&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20688255%26dopt%3DAbstract Authors: Tewari R, Bailes E, Bunting KA, Coates JC Armadillo (ARM)-repeat proteins form a large family with diverse and fundamental functions in many eukaryotes. ARM-repeat proteins have largely been characterised in multicellular organisms and much is known about how a subset of these proteins function. The structure of ARM-repeats allows proteins containing them to be functionally very versatile. Are the ARM-repeat proteins in 'little creatures' as multifunctional as their better-studied relatives? The time is now right to start analysing ARM-repeat proteins in these new systems to better understand their cell biology. Here, we review recent advances in understanding the many cellular roles of both well-known and novel ARM-repeat proteins. PMID: 20688255 [PubMed - as supplied by ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3855640 Sat, 31 Jul 2010 23:00:00 +0100 3855640 http://www.medworm.com/index.php?rid=3825329&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20674361%26dopt%3DAbstract Authors: Carvalho L, Heisenberg CP The yolk syncytial layer (YSL) plays crucial roles in early zebrafish development. The YSL is a transient extra-embryonic syncytial tissue that forms during early cleavage stages and persists until larval stages. During gastrulation, the YSL undergoes highly dynamic movements, which are tightly coordinated with the movements of the overlying germ layer progenitor cells, and has critical functions in cell fate specification and morphogenesis of the early germ layers. Movement coordination between the YSL and blastoderm cells is dependent on contact between these tissues, and is probably required for the patterning and morphogenetic function of the YSL. In this review, we will discuss recent advances in elucidating the molecular and cellular mechanisms ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3825329 Wed, 28 Jul 2010 23:00:00 +0100 3825329 http://www.medworm.com/index.php?rid=3806157&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20667736%26dopt%3DAbstract Authors: Roukos V, Misteli T, Schmidt CK The next revolution in microscopy is upon us: it is High-Throughput Imaging (HTI). In HTI large numbers of images from many samples are acquired and analyzed. This has become possible due to a confluence of dramatic progress in microscope engineering, enabling efficient image collection, and the availability of high computing power for data analysis. Combining HTI with genome-wide RNA interference (RNAi)-based gene knockdown technology offers a powerful approach for unbiased discovery of cellular mechanisms. PMID: 20667736 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3806157 Sun, 25 Jul 2010 23:00:00 +0100 3806157 http://www.medworm.com/index.php?rid=3795583&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20656489%26dopt%3DAbstract Authors: Maslon MM, Hupp TR Missense mutations in the p53 gene are commonly selected for in developing human cancer cells. These diverse mutations in p53 can inactivate its normal sequence-specific DNA-binding and transactivation function, but these mutations can also stabilize a mutant form of p53 with pro-oncogenic potential. Recent multi-disciplinary advances have demonstrated exciting and unexpected potential in therapeutically targeting the mutant p53 pathway, including: the development of biophysical models to explain how mutations inactivate p53 and strategies for refolding and reactivation of mutant p53, the ability of mutant p53 protein to escape MDM2-mediated degradation in human cancers, and the growing 'interactome' of mutant p53 that begins to explain how the mutant p53 pr... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3795583 Thu, 22 Jul 2010 23:00:00 +0100 3795583 http://www.medworm.com/index.php?rid=3795582&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20656490%26dopt%3DAbstract Authors: Pardali E, Goumans MJ, Ten Dijke P Members of the transforming growth factor-beta (TGF-beta) family play pivotal roles in development and disease. These cytokines elicit their pleiotropic effects on cells, including endothelial and mural cells, through specific type I and type II serine/threonine kinase receptors and intracellular Smad transcription factors. This review highlights recent progress in our understanding of TGF-beta signaling in vascular development and angiogenesis and of how perturbed TGF-beta signaling might contribute to vascular pathologies, tumor angiogenesis and tumor progression. Recent research has provided exciting insights into the role of the TGF-beta type I receptor (ALK1) in tumor angiogenesis and the curative effects of thalidomide on vascular malfo... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3795582 Thu, 22 Jul 2010 23:00:00 +0100 3795582 http://www.medworm.com/index.php?rid=3795584&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20655749%26dopt%3DAbstract Authors: Derijck AA, Van Erp S, Pasterkamp RJ To establish axonal connections growth cones must navigate multiple intermediate targets before reaching their final target. During this journey growth cones are guided by extracellular repulsive and attractive signals. Although initially identified as repulsive molecules, members of the semaphorin family include both attractants and repellents. How a navigating growth cone responds to a specific semaphorin is not absolute but instead depends on the biological context in which this cue is encountered. Here we review recent breakthroughs in our understanding of the extrinsic signals and molecular processes that control growth cone responses to class 3 semaphorins (Sema3s) at a well-characterized intermediate target, the spinal cord midline. ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3795584 Wed, 21 Jul 2010 23:00:00 +0100 3795584 http://www.medworm.com/index.php?rid=3761819&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20630759%26dopt%3DAbstract Authors: Gibbings D, Voinnet O Recent advances in the cell biology of RNA silencing have unraveled an intriguing association of post-transcriptionally regulated RNA with endolysosomal membranes in several circumstances of mRNA localization, microRNA activity and viral RNA transport and packaging. Endolysosomal membranes are a nexus of communication and transport between cells and their exterior environment for signaling receptors, pathogens and nutrients. Here, we discuss recent data that support a view that endolysosomal positioning of RNA might facilitate intercellular transmission of RNA and host defence against viruses and retrotransposons. Positioning of RNA regulatory mechanisms on endolysosomal membranes might permit rapid and localized control of microRNA (miRNA) gene regulator... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3761819 Sun, 11 Jul 2010 23:00:00 +0100 3761819 http://www.medworm.com/index.php?rid=3761818&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20630760%26dopt%3DAbstract Authors: Cibois M, Gautier-Courteille C, Legagneux V, Paillard L Living organisms undergo biochemical, physiological and behavioral cycles with periods ranging from seconds to years. Cycles with intermediate periods are governed by endogenous clocks that depend on oscillating gene expression. Here we illustrate the modalities and specific functions of post-transcriptional control of gene expression (exerted on pre-mRNAs and mRNAs) in biological clocks through two examples: the circadian clock and the vertebrate somite segmentation clock, an embryonic clock with a period far below a day. We conclude that both constitutive and cyclic post-transcriptional controls underpin clock function. PMID: 20630760 [PubMed - as supplied by publisher] (Source: Trends in Cell Biology) Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3761818 Sun, 11 Jul 2010 23:00:00 +0100 3761818 http://www.medworm.com/index.php?rid=3750804&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20620062%26dopt%3DAbstract Authors: Skibbens RV The time between chromosome replication and segregation can be from hours to decades. Cohesion is thus crucial for identifying replication products as sister chromatids from S-phase until mitosis. Early models posited active sister chromatid tethering reactions in which cohesins deposited onto each sister chromatid are converted to a paired state by replication-fork-associated establishment factors. Subsequent, but now largely marginalized, models suggested instead that establishment occurs passively - requiring only cohesin preloading and passage of the replication fork through huge cohesin rings. More recent models return to active establishment reactions but remain predicated on preloaded ring structures. Here, new models are presented in which replication-coupl... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3750804 Wed, 07 Jul 2010 23:00:00 +0100 3750804 http://www.medworm.com/index.php?rid=3734421&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20598543%26dopt%3DAbstract Authors: Plaza S, Chanut-Delalande H, Fernandes I, Wassarman PM, Payre F The terminal differentiation of epithelial cells involves changes in the apical compartment, including remodeling of the cytoskeleton and junctions to modify its three-dimensional organization. It also often triggers the building of specialized extracellular matrices, the function of which remains poorly understood. Hundreds of extracellular matrix proteins expressed in a variety of epithelia possess a conserved region called the zona pellucida-domain (ZP domain). There is evidence to suggest that ZP-domains mediate the polymerization of proteins into fibrils or matrices and that mutation of ZP-domains can result in severe pathologies, such as infertility, deafness, and cancer. Recent work in worms and flies demon... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3734421 Tue, 29 Jun 2010 23:00:00 +0100 3734421 http://www.medworm.com/index.php?rid=3663131&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20541937%26dopt%3DAbstract Authors: Arkov AL, Ramos A The germline originates from primordial embryonic germ cells which give rise to sperm and egg cells and consequently, to the next generation. Germ cells of many organisms contain electron-dense granules that comprise RNA and proteins indispensable for germline development. Here we review recent reports that provide important insights into the structure and function of crucial RNA and protein components of the granules, including DEAD-box helicases, Tudor domain proteins, Piwi/Argonaute proteins and piRNA. Collectively, these components function in translational control, remodeling of ribonucleoprotein complexes and transposon silencing. Furthermore, they interact with each other by means of conserved structural modules and post-translationally modified amino ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3663131 Wed, 09 Jun 2010 23:00:00 +0100 3663131 http://www.medworm.com/index.php?rid=3663130&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20541938%26dopt%3DAbstract Authors: Johnson JL, Leroux MR An exciting discovery of the new millennium is that primary cilia, organelles found on most eukaryotic cells, play crucial roles in vertebrate development by modulating Hedgehog, Wnt and PDGF signaling. Analysis of the literature and sequence databases reveals that the ancient signal transduction pathway, which uses cGMP in eukaryotes or related cyclic di-GMP in bacteria, exists in virtually all eukaryotes. However, many eukaryotes that secondarily lost cilia during evolution, including flowering plants, slime molds and most fungi, lack otherwise evolutionarily conserved cGMP signaling components. Based on this intriguing phylogenetic distribution, the presence of cGMP signaling proteins within cilia, and the indispensable roles that cGMP plays in transdu... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3663130 Wed, 09 Jun 2010 23:00:00 +0100 3663130 http://www.medworm.com/index.php?rid=3600230&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20493706%26dopt%3DAbstract Authors: Shivas JM, Morrison HA, Bilder D, Skop AR The establishment and maintenance of polarized plasma membrane domains is essential for cellular function and proper development of organisms. The molecules and pathways involved in determining cell polarity are remarkably well conserved between animal species. Historically, exocytic mechanisms have received primary emphasis among trafficking routes responsible for cell polarization. Accumulating evidence now reveals that endocytosis plays an equally important role in the proper localization of key polarity proteins. Intriguingly, some polarity proteins can also regulate the endocytic machinery. Here, we review emerging evidence for the reciprocal regulation between polarity proteins and endocytic pathways, and discuss possible models ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3600230 Tue, 18 May 2010 23:00:00 +0100 3600230 http://www.medworm.com/index.php?rid=3582474&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20471271%26dopt%3DAbstract Authors: McConnell RE, Tyska MJ Class 1 myosins are small motor proteins with the ability to simultaneously bind to actin filaments and cellular membranes. Given their ability to generate mechanical force, and their high prevalence in many cell types, these molecules are well positioned to carry out several important biological functions at the interface of membrane and the actin cytoskeleton. Indeed, recent studies implicate these motors in endocytosis, exocytosis, release of extracellular vesicles, and the regulation of tension between membrane and the cytoskeleton. Many class 1 myosins also exhibit a load-dependent mechano-chemical cycle that enables them to maintain tension for long periods of time without hydrolyzing ATP. These properties put myosins-1 in a unique position to regu... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3582474 Tue, 11 May 2010 23:00:00 +0100 3582474 http://www.medworm.com/index.php?rid=3556946&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20452772%26dopt%3DAbstract Authors: Oh H, Irvine KD The Hippo signaling pathway is a key regulator of growth during animal development, whereas loss of normal Hippo pathway activity is associated with a wide range of cancers. Hippo signaling represses growth by inhibiting the activity of a transcriptional co-activator protein, known as Yorkie in Drosophila and Yap in vertebrates. In the 5 years since the first report linking Yorkie to Hippo signaling, intense interest in this pathway has led to rapid increases in our understanding of the action and regulation of Yorkie/Yap, which we review here. These studies have also emphasized the complexity of Yorkie/Yap regulation, including multiple, distinct mechanisms for repressing its transcriptional activity, and multiple DNA-binding partner proteins that can direct Y... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3556946 Thu, 06 May 2010 23:00:00 +0100 3556946 http://www.medworm.com/index.php?rid=3539147&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20444605%26dopt%3DAbstract Authors: Weil TT, Parton RM, Davis I Localized mRNA provides spatial and temporal protein expression essential to cell development and physiology. To explore the mechanisms involved, considerable effort has been spent in establishing new and improved methods for visualizing mRNA. Here, we discuss how these techniques have extended our understanding of intracellular mRNA localization in a variety of organisms. In addition to increased ease and specificity of detection in fixed tissue, in situ hybridization methods now enable examination of mRNA distribution at the ultrastructural level with electron microscopy. Most significantly, methods for following the movement of mRNA in living cells are now in widespread use. These include the introduction of labeled transcripts by microinjection,... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3539147 Sun, 02 May 2010 23:00:00 +0100 3539147 http://www.medworm.com/index.php?rid=3539146&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20444606%26dopt%3DAbstract Authors: You Z, Bailis JM Maintenance of genome stability depends on efficient, accurate repair of DNA damage. DNA double-strand breaks (DSBs) are among the most lethal types of DNA damage, with the potential to cause mutation, chromosomal rearrangement, and genomic instability that could contribute to cancer. DSB damage can be repaired by various pathways including nonhomologous end-joining (NHEJ) and homologous recombination (HR). However, the cellular mechanisms that regulate the choice of repair pathway are not well understood. Recent studies suggest that the tumor suppressor protein CtIP controls the decision to repair DSB damage by HR. It does so by regulating the initiation of DSB end resection after integrating signals from the DNA damage checkpoint response and cell cycle cues... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3539146 Sun, 02 May 2010 23:00:00 +0100 3539146 http://www.medworm.com/index.php?rid=3532382&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20434915%26dopt%3DAbstract Authors: Deng Y, Almsherqi ZA, Ng MM, Kohlwein SD Biological membranes with cubic morphology are a hallmark of stressed or diseased cellular conditions; both protein-protein interactions and lipid alterations appear to contribute to their biogenesis, yet their specific cellular functions are unknown. The occurrence of cubic membranes strikingly correlates with viral infections; notably, virus entry, proliferation, and release are processes closely linked to cellular cholesterol metabolism, and dys-regulation of cholesterol synthesis at the level of HMG-CoA reductase also induces cubic membrane formation, in the absence of viral infection. We propose that virus-induced cubic membranes could result from viral interference of cellular cholesterol homeostasis, generating a protective membr... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3532382 Wed, 28 Apr 2010 23:00:00 +0100 3532382 http://www.medworm.com/index.php?rid=3522935&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20427185%26dopt%3DAbstract Authors: Bedford L, Paine S, Sheppard PW, Mayer RJ, Roelofs J The 26S proteasome is a large multiprotein complex involved in the regulated degradation of ubiquitinated proteins in the cell. The 26S proteasome has been shown to control an increasing number of essential biochemical mechanisms of the cellular lifecycle including DNA synthesis, repair, transcription, translation, and cell signal transduction. Concurrently, it is increasingly seen that malfunction of the ubiquitin proteasome system contributes to the pathogenesis of disease. The recent identification of four molecular chaperones, in addition to five previously identified chaperones, have provided mechanistic insight into how this cellular megastructure is assembled in the cell. These data, together with new insights into th... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3522935 Sun, 25 Apr 2010 23:00:00 +0100 3522935 http://www.medworm.com/index.php?rid=3483737&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20399659%26dopt%3DAbstract Authors: Mayor R, Carmona-Fontaine C Contact inhibition of locomotion (CIL) is the process by which cells in vitro change their direction of migration upon contact with another cell. Here, we revisit the concept that CIL plays a central role in the migration of single cells and in collective migration, during both health and disease. Importantly, malignant cells exhibit a diminished CIL behaviour which allows them to invade healthy tissues. Accumulating evidence indicates that CIL occurs in vivo and that regulation of small Rho GTPases is important in the collapse of cell protrusions upon cell contact, the first step of CIL. Finally, we propose possible cell surface proteins that could be involved in the initial contact that regulates Rho GTPases during CIL. PMID: 20399659 [PubMed ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3483737 Wed, 14 Apr 2010 23:00:00 +0100 3483737 http://www.medworm.com/index.php?rid=3483736&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20399660%26dopt%3DAbstract Authors: Feng Z, Levine AJ In response to stress, p53 initiates the transcriptional regulation of selected target genes and various cellular responses, including cell cycle arrest, apoptosis and senescence. Recent studies revealed two additional functions of p53 in the regulation of IGF-1/AKT/mTOR pathways and energy metabolism, contributing to p53's role as a tumor suppressor. Oncogenic processes give rise to metabolic pathways focused upon the use of aerobic glycolysis (the Warburg effect) and the pentose shunt, providing higher levels of reducing activities. p53 shuts down these pathways and refocuses cells to utilize mitochondrial oxidative phosphorylation, thereby maximizing efficient ATP production and minimizing the synthesis of substrates for cell division. The use of these alt... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3483736 Wed, 14 Apr 2010 23:00:00 +0100 3483736 http://www.medworm.com/index.php?rid=3468398&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20382532%26dopt%3DAbstract Authors: Kim J, Eberwine J It has become increasingly clear that the genome is dynamic and exquisitely sensitive, changing expression patterns in response to age, environmental stimuli and pharmacological and physiological manipulations. Similarly, cellular phenotype, traditionally viewed as a stable end-state, should be viewed as versatile and changeable. The phenotype of a cell is better defined as a 'homeostatic phenotype' implying plasticity resulting from a dynamically changing yet characteristic pattern of gene/protein expression. A stable change in phenotype is the result of the movement of a cell between different multidimensional identity spaces. Here, we describe a key driver of this transition and the stabilizer of phenotype: the relative abundances of the cellular RNAs. We ... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3468398 Thu, 08 Apr 2010 23:00:00 +0100 3468398 http://www.medworm.com/index.php?rid=3435307&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20359892%26dopt%3DAbstract Authors: Nishita M, Enomoto M, Yamagata K, Minami Y Correct spatio-temporal regulation of Wnt5a signaling is required for normal developmental morphogenesis, and defects in this pathway are linked to tumorigenesis. The precise role of Wnt5a signaling in cancer has, however, been a matter of controversy. Loss of Wnt5a signaling is related to development of lymphoid malignancies, whereas constitutively active Wnt5a signaling is involved in invasion or metastasis of several cancers. Interestingly, recent studies in Drosophila and mouse have revealed that disrupted cell polarity might contribute to invasion/metastasis of cancers. Wnt5a activates the planar cell polarity (PCP) pathway, partly through the receptor tyrosine kinase Ror2. Here, we review developments in our understanding of the... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3435307 Mon, 29 Mar 2010 23:00:00 +0100 3435307 http://www.medworm.com/index.php?rid=3435308&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20356743%26dopt%3DAbstract Authors: Funderburk SF, Wang QJ, Yue Z An increasing body of research on autophagy provides overwhelming evidence for its connection to diverse biological functions and human diseases. Beclin 1, the first mammalian autophagy protein to be described, appears to act as a nexus point between autophagy, endosomal, and perhaps also cell death pathways. Beclin 1 performs these roles as part of a core complex that contains vacuolar sorting protein 34 (VPS34), a class III phosphatidylinositol-3 kinase. The precise mechanism of Beclin 1-mediated regulation of these cellular functions is unclear, but substantial progress has recently been made in identifying new players and their functions in Beclin 1-VSP34 complexes. Here we review emerging studies that are beginning to unveil the physiological... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3435308 Sun, 28 Mar 2010 23:00:00 +0100 3435308 http://www.medworm.com/index.php?rid=3391383&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20303758%26dopt%3DAbstract Authors: Balaburski GM, Hontz RD, Murphy ME p53 and ARF are well-established tumor-suppressor proteins that function together in the negative regulation of cancer. Recently, both proteins were found to play surprising roles in autophagy. Autophagy ('self-eating') is a crucial response of eukaryotic cells to metabolic and other stress. During this process, portions of the cytosol are sequestered into characteristic double-membrane vesicles that are delivered to the lysosome for degradation, leading to the release of free amino acids and promoting cell survival. The mechanisms whereby p53 and ARF control autophagy are only now becoming elucidated. An emerging question is whether we can develop metabolic poisons that preferentially destroy tumor cells depending on their reliance on autoph... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3391383 Thu, 18 Mar 2010 00:00:00 +0100 3391383 http://www.medworm.com/index.php?rid=3391384&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20303271%26dopt%3DAbstract Authors: Patel S, Docampo R Changes in cytosolic calcium concentration are crucial for a variety of cellular processes in all cells. It has long been appreciated that calcium is stored and released from intracellular calcium stores such as the endoplasmic reticulum. However, emerging evidence indicates that calcium is also dynamically regulated by a seemingly disparate collection of acidic organelles. In this paper, we review the defining features of these 'acidic calcium stores' and highlight recent progress in understanding the mechanisms of uptake and release of calcium from these stores. We also examine the nature of calcium buffering within the stores, and summarize the physiological and pathophysiological significance of these ubiquitous organelles in calcium signaling. PMID:... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3391384 Wed, 17 Mar 2010 00:00:00 +0100 3391384 http://www.medworm.com/index.php?rid=3386371&cid=s_36137_171_f&fid=36137&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20299221%26dopt%3DAbstract Authors: Forget AL, Kowalczykowski SC The Rad51 protein is essential for DNA repair by homologous recombination. After DNA damage, Rad51 localizes to nuclear foci that represent sites of DNA repair in vivo. In vitro, Rad51 self-assembles on single- or double-stranded DNA to form a nucleoprotein filament. Recently, the merging of innovative single-molecule techniques with ensemble methods has provided unique insights into the dynamic nature of this filament and its cellular function. The assembly and disassembly of Rad51 nucleoprotein filaments is seen to be regulated by recombination accessory proteins. In this regard, the BRC repeats of the BRCA2 protein were shown to modulate the DNA binding selectivity of Rad51. Furthermore, single-molecule studies explained the need for a DNA trans... Trends in Cell Biology journals http://www.medworm.com/rss/comments.php?id=3386371 Tue, 16 Mar 2010 00:00:00 +0100 3386371