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 'Annual Review of Cell and Developmental Biology' source. Sat, 07 Jan 2012 16:34:20 +0100 http://www.medworm.com/index.php?rid=5313247&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21985671%26dopt%3DAbstract Authors: Lunt SY, Vander Heiden MG Abstract Warburg's observation that cancer cells exhibit a high rate of glycolysis even in the presence of oxygen (aerobic glycolysis) sparked debate over the role of glycolysis in normal and cancer cells. Although it has been established that defects in mitochondrial respiration are not the cause of cancer or aerobic glycolysis, the advantages of enhanced glycolysis in cancer remain controversial. Many cells ranging from microbes to lymphocytes use aerobic glycolysis during rapid proliferation, which suggests it may play a fundamental role in supporting cell growth. Here, we review how glycolysis contributes to the metabolic processes of dividing cells. We provide a detailed accounting of the biosynthetic requirements to construct a new cell and ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5313247 Fri, 14 Oct 2011 12:55:20 +0100 5313247 http://www.medworm.com/index.php?rid=5313246&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21985672%26dopt%3DAbstract Authors: Hobert O Abstract The generation of individual neuron types in the nervous system is a multistep process whose endpoint is the expression of neuron type-specific batteries of terminal differentiation genes that determine the functional properties of a neuron. This review focuses on the regulatory mechanisms that are involved in controlling the terminally differentiated state of a neuron. I review several case studies from invertebrate and vertebrate nervous systems that reveal that many terminal differentiation features of a neuron are coregulated via terminal selector transcription factors that initiate and maintain terminal differentiation programs. PMID: 21985672 [PubMed - in process] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=5313246 Fri, 14 Oct 2011 12:55:11 +0100 5313246 http://www.medworm.com/index.php?rid=4961688&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663443%26dopt%3DAbstract Authors: Ivaska J, Heino J All multicellular animals express receptors for growth factors (GFs) and extracellular matrix (ECM) molecules. Integrin-type ECM receptors anchor cells to their surroundings and concomitantly activate intracellular signal transduction pathways. The same signaling mechanisms are regulated by GF receptors (GFRs). Recently, intensive research efforts have revealed novel mechanisms describing how the two receptor systems collaborate at many different levels. Integrins can directly bind to GFs and promote their activation. Adhesion receptors also organize signaling platforms and assist GFRs or even activate them via ligand-independent mechanisms. Furthermore, integrins can orchestrate endocytosis and recycling of GFRs. Here, we review the present knowledge about t... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4961688 Thu, 09 Jun 2011 23:00:00 +0100 4961688 http://www.medworm.com/index.php?rid=4961687&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663444%26dopt%3DAbstract Authors: Kim C, Ye F, Ginsberg MH Regulation of cell-cell and cell-matrix interaction is essential for the normal physiology of metazoans and is important in many diseases. Integrin adhesion receptors can rapidly increase their affinity (integrin activation) in response to intracellular signaling events in a process termed inside-out signaling. The transmembrane domains of integrins and their interactions with the membrane are important in inside-out signaling. Moreover, integrin activation is tightly regulated by a complex network of signaling pathways. Here, we review recent progress in understanding how the membrane environment can, in cooperation with integrin-binding proteins, regulate integrin activation. Expected final online publication date for the Annual Review of Cell and De... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4961687 Thu, 09 Jun 2011 23:00:00 +0100 4961687 http://www.medworm.com/index.php?rid=4912710&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639798%26dopt%3DAbstract Authors: Sengupta D, Linstedt AD The Golgi complex processes secretory proteins and lipids, carries out protein sorting and signaling, and supports growth and composition of the plasma membrane. Golgi complex size likely is regulated to meet the demands of each function, and this may involve differential changes of its distinct subdomains. Nevertheless, the primary size change is elongation of the Golgi ribbon-like network as occurs during Golgi complex doubling for mitosis and during differentiation involving upregulated secretion. One hypothesis states that Golgi complex size is set by the abundance of secretory cargo and Golgi complex components that, through binding vesicle coat complexes, drive vesicle coat formation to alter Golgi complex influx and efflux. Regulation of transpor... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4912710 Mon, 30 May 2011 23:00:00 +0100 4912710 http://www.medworm.com/index.php?rid=4912702&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639799%26dopt%3DAbstract Authors: Rock JR, Hogan BL The vertebrate lung is elegantly patterned to carry out gas exchange and host defense. Similar to other organ systems, endogenous stem and progenitor cells fuel the organogenesis of the lung and maintain homeostasis in the face of normal wear and tear. In the context of acute injury, these progenitor populations are capable of effecting efficient repair. However, chronic injury, inflammation, and immune rejection frequently result in pathological airway remodeling and serious impairment of lung function. Here, we review the development, maintenance, and repair of the vertebrate respiratory system with an emphasis on the roles of epithelial stem and progenitor cells. We discuss what is currently known about their identities, lineage relationships, and the mech... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4912702 Mon, 30 May 2011 23:00:00 +0100 4912702 http://www.medworm.com/index.php?rid=4912695&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21639800%26dopt%3DAbstract Authors: Hartman MA, Finan D, Sivaramakrishnan S, Spudich JA Unconventional myosins are a superfamily of actin-based motors implicated in diverse cellular processes. In recent years, much progress has been made in describing their biophysical properties, and headway has been made into analyzing their cellular functions. Here, we focus on the principles that guide in vivo motor function and targeting to specific cellular locations. Rather than describe each motor comprehensively, we outline the major themes that emerge from research across the superfamily and use specific examples to illustrate each. In presenting the data in this format, we seek to identify open questions in each field as well as to point out commonalities between them. To advance our understanding of myosins' roles in... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4912695 Mon, 30 May 2011 23:00:00 +0100 4912695 http://www.medworm.com/index.php?rid=4865860&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21599493%26dopt%3DAbstract Authors: Schmid SL, Frolov VA Dynamin, best studied for its role in clathrin-mediated endocytosis, is the prototypical member of a family of multidomain GTPases involved in fission and remodeling of multiple organelles. Recent studies have shown that dynamin alone can catalyze fission of membrane tubules and vesicle formation from planar lipid templates. Thus, dynamin appears to be a self-sufficient fission machine. Here we review the biochemical activities and structural features of dynamin required for fission activity. As all changes in membrane topology require energetically unfavorable rearrangements of the lipid bilayer, we discuss the interplay between dynamin and its lipid substrates that are critical to defining a nonleaky pathway to membrane fission. We propose a two-stage mo... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4865860 Tue, 17 May 2011 23:00:00 +0100 4865860 http://www.medworm.com/index.php?rid=4865861&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21568710%26dopt%3DAbstract Authors: Leitinger B Collagen, the most abundant protein in animals, is a key component of extracellular matrices. Collagens not only provide essential structural support for connective tissues, but they are also intimately involved in controlling a spectrum of cellular functions such as growth, differentiation, and morphogenesis. All collagens possess triple-helical regions through which they interact with a host of other proteins including cell surface receptors. A structurally diverse group of transmembrane receptors mediates the recognition of the collagen triple helix: integrins, discoidin domain receptors, glycoprotein VI, and leukocyte-associated immunoglobulin-like receptor-1. These collagen receptors regulate a wide range of behaviors including cell adhesion and migration, hem... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4865861 Thu, 12 May 2011 23:00:00 +0100 4865861 http://www.medworm.com/index.php?rid=4865862&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21568709%26dopt%3DAbstract Authors: Raff M In this Perspective, I review my scientific career, which began after I trained in medicine in Montreal and in neurology in Boston. I started in immunology in London with Avrion Mitchison, using antibodies against cell-surface antigens to study the development and functions of mouse T and B cells. The finding that antibody binding causes immunoglobulin on B cells to redistribute rapidly on the cell surface and be endocytosed transformed me from an immunologist into a cell biologist. I moved with Mitchison to University College London, where my colleagues and I used the antibody approach to study cells of the rodent nervous system, focusing on the intrinsic and extrinsic molecular mechanisms that control the development and behavior of myelinating glial cells-Schwann cel... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4865862 Wed, 11 May 2011 23:00:00 +0100 4865862 http://www.medworm.com/index.php?rid=4065584&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20929311%26dopt%3DAbstract Authors: Gerhart J In the 1950s, cellular regulatory mechanisms were newly recognized; with Arthur Pardee I investigated the initial enzyme of pyrimidine biosynthesis, which he discovered is controlled by feedback inhibition. The protein proved unusual in having separate but interacting sites for substrates and regulators. Howard Schachman and I dissociated the protein into different subunits, one binding regulators and one substrates. The enzyme became an early prime example of allostery. In developmental biology I studied the egg of the frog, Xenopus laevis, characterizing early processes of axis formation. My excellent students and I described cortical rotation, a 30° movement of the egg's cortex over tracks of parallel microtubules anchored to the underlying cytoplasmic ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4065584 Thu, 14 Oct 2010 12:00:16 +0100 4065584 http://www.medworm.com/index.php?rid=4065582&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20929312%26dopt%3DAbstract Authors: Hubber A, Roy CR Macrophages and protozoa ingest bacteria by phagocytosis and destroy these microbes using a conserved pathway that mediates fusion of the phagosome with lysosomes. To survive within phagocytic host cells, bacterial pathogens have evolved a variety of strategies to avoid fusion with lysosomes. A virulence strategy used by the intracellular pathogen Legionella pneumophila is to manipulate host cellular processes using bacterial proteins that are delivered into the cytosolic compartment of the host cell by a specialized secretion system called Dot/Icm. The proteins delivered by the Dot/Icm system target host factors that play evolutionarily conserved roles in controlling membrane transport in eukaryotic cells, which enables L. pneumophila to create an endoplasmic... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4065582 Thu, 14 Oct 2010 12:00:12 +0100 4065582 http://www.medworm.com/index.php?rid=4065581&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20929313%26dopt%3DAbstract Authors: Toomre D, Bewersdorf J Fluorescence imaging methods that push or break the diffraction limit of resolution (approximately 200 nm) have grown explosively. These super-resolution nanoscopy techniques include: stimulated emission depletion (STED), Pointillism microscopy [(fluorescence) photoactivation localization microscopy/stochastic optical reconstruction microscopy, or (F)PALM/STORM], structured illumination, total internal reflection fluorescence microscopy (TIRFM), and those that combine multiple modalities. Each affords unique strengths in lateral and axial resolution, speed, sensitivity, and fluorophore compatibility. We examine the optical principles and design of these new instruments and their ability to see more detail with greater sensitivity--down to single molecule... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=4065581 Thu, 14 Oct 2010 12:00:07 +0100 4065581 http://www.medworm.com/index.php?rid=3750784&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20624054%26dopt%3DAbstract Authors: Lessard J, Crabtree GR Stem cells of all types are characterized by a stable, heritable state permissive of multiple developmental pathways. The past five years have seen remarkable advances in understanding these heritable states and the ways that they are initiated or terminated. Transcription factors that bind directly to DNA and have sufficiency roles have been most easy to investigate and, perhaps for this reason, are most solidly implicated in pluripotency. In addition, large complexes of ATP-dependent chromatin-remodeling and histone-modification enzymes that have specialized functions have also been implicated by genetic studies in initiating and/or maintaining pluripotency or multipotency. Several of these ATP-dependent remodeling complexes play non-redundant roles, a... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3750784 Sun, 11 Jul 2010 23:00:00 +0100 3750784 http://www.medworm.com/index.php?rid=3734409&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20604707%26dopt%3DAbstract Authors: Musunuru K, Domian IJ, Chien KR The past few years have witnessed remarkable advances in stem cell biology and human genetics, and we have arrived at an era in which patient-specific cell and tissue models are now practical. The recent identification of cardiovascular progenitor cells, as well as the identification of genetic variants underlying congenital heart disorders and adult disease, opens the door to the development of human models of human cardiovascular disease. We review the current understanding of the contribution of progenitor cells to cardiogenesis and outline how pluripotent stem cells can be applied to the modeling of cardiovascular disorders of genetic origin. A key challenge will be to implement these models in an efficient manner to develop a molecular unde... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3734409 Mon, 05 Jul 2010 23:00:00 +0100 3734409 http://www.medworm.com/index.php?rid=3734408&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20604708%26dopt%3DAbstract We describe postsynaptic ubiquitination pathways and their role in brain development, neuronal physiology, and brain disorders. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 26 is October 06, 2010. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID: 20604708 [PubMed - as supplied by publisher] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3734408 Mon, 05 Jul 2010 23:00:00 +0100 3734408 http://www.medworm.com/index.php?rid=3734407&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20604709%26dopt%3DAbstract Authors: Goshima G, Scholey JM The mitotic spindle accurately segregates genetic instructions by moving chromosomes to spindle poles (anaphase A) and separating the poles (anaphase B) so that, in general, the chromosomes and poles are positioned near the center of the nascent daughter cell products of each cell division. Because the size of different types of dividing cells, and thus the spacing of their daughter cell centers, can vary significantly, the length of the metaphase or postanaphase B spindle often scales with cell size. However, significant exceptions to this scaling rule occur, revealing the existence of cell size-independent, spindle-associated mechanisms of spindle length control. The control of spindle length reflects the action of mitotic force-generating mechanisms, a... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3734407 Mon, 05 Jul 2010 23:00:00 +0100 3734407 http://www.medworm.com/index.php?rid=3734406&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20604710%26dopt%3DAbstract Authors: De Strooper B, Annaert W Presenilins are the catalytic subunits of larger tetrameric gamma-secretase complexes. The degradome of these aspartyl proteases consists of at least 60 different substrates. gamma-Secretase is key to regulated intramembrane proteolysis, releasing protein fragments that potentially transduce signals at both sides of the cell membrane. Characteristic for this novel form of cellular signaling is its irreversible nature, providing direction to biological processes. We discuss recent insights in structure function and assembly of the gamma-secretase complexes and emerging insights in the regulation of the activity of these enzymes. This novel knowledge will help to develop better drugs for Alzheimer's disease and cancer. We critically evaluate literature t... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3734406 Mon, 05 Jul 2010 23:00:00 +0100 3734406 http://www.medworm.com/index.php?rid=3734405&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20604711%26dopt%3DAbstract Authors: Chuang HY, Hofree M, Ideker T Systems biology provides a framework for assembling models of biological pathways from systematic measurements. Since the field was first introduced a decade ago, considerable progress has been made in technologies for global cell measurement and in computational analyses of these data to map and model cell function. It has also greatly expanded into the translational sciences, with approaches pioneered in yeast now being applied to elucidate human development and disease. Here, we review the state of the field with a focus on four emerging applications of systems biology that are likely to be of particular importance during the decade to follow: (a) pathway-based biomarkers, (b) global genetic interaction maps, (c) systems approaches to identify ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3734405 Mon, 05 Jul 2010 23:00:00 +0100 3734405 http://www.medworm.com/index.php?rid=3722212&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20590451%26dopt%3DAbstract Authors: Lumba S, Cutler S, McCourt P Plant hormones are a group of chemically diverse small molecules that direct processes ranging from growth and development to biotic and abiotic stress responses. Surprisingly, genome analyses suggest that classic animal nuclear hormone receptor homologs do not exist in plants. It now appears that plants have co-opted several protein families to perceive hormones within the nucleus. In one solution to the problem, the hormones auxin and jasmonate ( JA) act as "molecular glue" that promotes protein-protein interactions between receptor F-boxes and downstream corepressor targets. In another solution, gibberellins (GAs) bind and elicit a conformational change in a novel soluble receptor family related to hormone-sensitive lipases. Abscisic acid (ABA),... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3722212 Mon, 28 Jun 2010 23:00:00 +0100 3722212 http://www.medworm.com/index.php?rid=3722211&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20590452%26dopt%3DAbstract Authors: Keung AJ, Kumar S, Schaffer DV Stem cells reside in adult and embryonic tissues in a broad spectrum of developmental stages and lineages, and they are thus naturally exposed to diverse microenvironments or niches that modulate their hallmark behaviors of self-renewal and differentiation into one or more mature lineages. Within each such microenvironment, stem cells sense and process multiple biochemical and biophysical cues, which can exert redundant, competing, or orthogonal influences to collectively regulate cell fate and function. The proper presentation of these myriad regulatory signals is required for tissue development and homeostasis, and their improper appearance can potentially lead to disease. Whereas these complex regulatory cues can be challenging to dissect usin... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3722211 Mon, 28 Jun 2010 23:00:00 +0100 3722211 http://www.medworm.com/index.php?rid=3722210&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20590453%26dopt%3DAbstract Authors: Johnston Jr RJ, Desplan C Although cell fate specification is tightly controlled to yield highly reproducible results and avoid extreme variation, developmental programs often incorporate stochastic mechanisms to diversify cell types. Stochastic specification phenomena are observed in a wide range of species and an assorted set of developmental contexts. In bacteria, stochastic mechanisms are utilized to generate transient subpopulations capable of surviving adverse environmental conditions. In vertebrate, insect, and worm nervous systems, stochastic fate choices are used to increase the repertoire of sensory and motor neuron subtypes. Random fate choices are also integrated into developmental programs controlling organogenesis. Although stochastic decisions can be maintained ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3722210 Mon, 28 Jun 2010 23:00:00 +0100 3722210 http://www.medworm.com/index.php?rid=3722209&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20590454%26dopt%3DAbstract Authors: Caño-Delgado A, Lee JY, Demura T Plant vascular tissues, the conduits of water, nutrients, and small molecules, play important roles in plant growth and development. Vascular tissues have allowed plants to successfully adapt to various environmental conditions since they evolved 450 Mya. The majority of plant biomass, an important source of renewable energy, comes from the xylem of the vascular tissues. Efforts have been made to identify the underlying mechanisms of cell specification and patterning of plant vascular tissues and their proliferation. The formation of the plant vascular system is a complex process that integrates signaling and gene regulation at transcriptional and posttranscriptional levels. Recently, a wealth of molecular genetic studies and the advent of c... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3722209 Mon, 28 Jun 2010 23:00:00 +0100 3722209 http://www.medworm.com/index.php?rid=3692029&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20565253%26dopt%3DAbstract Authors: Couchman JR Virtually all metazoan cells contain at least one and usually several types of transmembrane proteoglycans. These are varied in protein structure and type of polysaccharide, but the total number of vertebrate genes encoding transmembrane proteoglycan core proteins is less than 10. Some core proteins, including those of the syndecans, always possess covalently coupled glycosaminoglycans; others do not. Syndecan has a long evolutionary history, as it is present in invertebrates, but many other transmembrane proteoglycans are vertebrate inventions. The variety of proteins and their glycosaminoglycan chains is matched by diverse functions. However, all assume roles as coreceptors, often working alongside high-affinity growth factor receptors or adhesion receptors such ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3692029 Sun, 20 Jun 2010 23:00:00 +0100 3692029 http://www.medworm.com/index.php?rid=3633950&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20521906%26dopt%3DAbstract Authors: Wickner W Although fusion mechanisms are highly conserved in evolution and among organelles of the exocytic and endocytic pathways, yeast vacuole homotypic fusion offers unique technical advantages: excellent genetics, clear organelle cytology, in vitro colorimetric fusion assays, and reconstitution of fusion from all-pure components, including a Rab GTPase, HOPS (homotypic fusion and vacuole protein sorting complex), four SNAREs [soluble N-ethylmaleimide-sensitive factor (NSF) attachment receptors] that snare (bind) each other, SNARE-complex disassembly chaperones, and vacuolar lipids. Vacuole fusion studies offer paradigms of the interdependence of lipids and fusion proteins to assemble a fusion microdomain, distinct lipid functions, SNARE complex proofreading through the sy... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3633950 Tue, 01 Jun 2010 23:00:00 +0100 3633950 http://www.medworm.com/index.php?rid=3610612&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20507227%26dopt%3DAbstract Authors: Starr DA, Fridolfsson HN The nuclear envelope links the cytoskeleton to structural components of the nucleus. It functions to coordinate nuclear migration and anchorage, organize chromatin, and aid meiotic chromosome pairing. Forces generated by the cytoskeleton are transferred across the nuclear envelope to the nuclear lamina through a nuclear-envelope bridge consisting of SUN (Sad1 and UNC-84) and KASH proteins (Klarsicht, ANC-1 and Syne/Nesprin homology). Some KASH-SUN combinations connect microtubules, centrosomes, actin filaments, or intermediate filaments to the surface of the nucleus. Other combinations are used in cell cycle control, nuclear import, or apoptosis. Interactions between the cytoskeleton and the nucleus also affect global cytoskeleton organization. SUN and... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3610612 Wed, 26 May 2010 23:00:00 +0100 3610612 http://www.medworm.com/index.php?rid=3610613&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20500090%26dopt%3DAbstract Authors: Auluck PK, Caraveo G, Lindquist S In the late 1990s, mutations in the synaptic protein alpha-synuclein (alpha-syn) were identified in families with hereditary Parkinson's disease (PD). Rapidly, alpha-syn became the target of numerous investigations that have transformed our understanding of the pathogenesis underlying this disorder. alpha-Syn is the major component of Lewy bodies (LBs), cytoplasmic protein aggregates that form in the neurons of PD patients. alpha-Syn interacts with lipid membranes and adopts amyloid conformations that deposit within LBs. Work in yeast and other model systems has revealed that alpha-syn-associated toxicity might be the consequence of abnormal membrane interactions and alterations in vesicle trafficking. Here we review evidence regarding alpha-s... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=3610613 Mon, 24 May 2010 23:00:00 +0100 3610613 http://www.medworm.com/index.php?rid=2872644&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19807280%26dopt%3DAbstract Authors: DeFalco T, Capel B A critical element of successful sexual reproduction is the generation of sexually dimorphic adult reproductive organs, the testis and ovary, which produce functional gametes. Examination of different vertebrate species shows that the adult gonad is remarkably similar in its morphology across different phylogenetic classes. Surprisingly, however, the cellular and molecular programs employed to create similar organs are not evolutionarily conserved. We highlight the mechanisms used by different vertebrate model systems to generate the somatic architecture necessary to support gametogenesis. In addition, we examine the different vertebrate patterns of germ cell migration from their site of origin to colonize the gonad and highlight their roles in sex-specific ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2872644 Thu, 08 Oct 2009 20:44:02 +0100 2872644 http://www.medworm.com/index.php?rid=2573579&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19572810%26dopt%3DAbstract Authors: Benning C Chloroplasts are the defining organelle of photoautotrophic plant cells. Photosynthetic light reactions and electron transport are the functions of an elaborate thylakoid membrane system inside chloroplasts. The lipid composition of photosynthetic membranes is characterized by a substantial fraction of nonphosphorous galactoglycerolipids reflecting the need of sessile plants to conserve phosphorus. Lipid transport and assembly of glycerolipids play an essential role in the biogenesis of the photosynthetic apparatus in developing chloroplasts. During chloroplast biogenesis, fatty acids are synthesized in the plastid and are exported to the endoplasmic reticulum, where they are incorporated into membrane lipids. Alternatively, lipids can also be assembled de novo at th... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2573579 Wed, 01 Jul 2009 23:00:00 +0100 2573579 http://www.medworm.com/index.php?rid=2526443&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19519166%26dopt%3DAbstract Authors: Gall JG Here I give a brief history of my scientific career, beginning with my early interest in natural history and my introduction to the microscope and the wonderful world of the cell. My studies have focused on chromosomes, nucleoli, and other nuclear structures, with a few forays into the cytoplasm. In each case, I have tried to understand how proteins and nucleic acids are physically organized to give rise to the structures seen in under the microscope. I describe how studies in my laboratory on amplified ribosomal RNA genes led to the development of in situ hybridization, a technique that permitted us to localize specific nucleic acid sequences with high precision. My early exposure to the diversity of animals and plants made it seem natural to choose organisms best sui... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=2526443 Wed, 10 Jun 2009 23:00:00 +0100 2526443 http://www.medworm.com/index.php?rid=1860420&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18837671%26dopt%3DAbstract Authors: Kleine-Vehn J, Friml J Plant development is characterized by a profound phenotypic plasticity that often involves redefining of the developmental fate and polarity of cells within differentiated tissues. The plant hormone auxin and its directional intercellular transport play a major role in these processes because they provide positional information and link cell polarity with tissue patterning. This plant-specific mechanism of transport-dependent auxin gradients depends on subcellular dynamics of auxin transport components, in particular on endocytic recycling and polar targeting. Recent insights into these cellular processes in plants have revealed important parallels to yeast and animal systems, including clathrin-dependent endocytosis, retromer function, and transcytosis,... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1860420 Wed, 08 Oct 2008 19:00:34 +0100 1860420 http://www.medworm.com/index.php?rid=1860419&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18837672%26dopt%3DAbstract Authors: Yang Z Cell polarization is intimately linked to plant development, growth, and responses to the environment. Major advances have been made in our understanding of the signaling pathways and networks that regulate cell polarity in plants owing to recent studies on several model systems, e.g., tip growth in pollen tubes, cell morphogenesis in the leaf epidermis, and polar localization of PINs. From these studies we have learned that plant cells use conserved mechanisms such as Rho family GTPases to integrate both plant-specific and conserved polarity cues and to coordinate the cytoskeketon dynamics/reorganization and vesicular trafficking required for polarity establishment and maintenance. This review focuses upon signaling mechanisms for cell polarity formation in Arabidopsis... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1860419 Wed, 08 Oct 2008 19:00:34 +0100 1860419 http://www.medworm.com/index.php?rid=1860418&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18837673%26dopt%3DAbstract Authors: Hattori D, Millard SS, Wojtowicz WM, Zipursky SL The Dscam family of immunoglobulin cell surface proteins mediates recognition events between neurons that play an essential role in the establishment of neural circuits. The Drosophila Dscam1 locus encodes tens of thousands of cell surface proteins via alternative splicing. These isoforms exhibit exquisite isoform-specific binding in vitro that mediates homophilic repulsion in vivo. These properties provide the molecular basis for self-avoidance, an essential developmental mechanism that allows axonal and dendritic processes to uniformly cover their synaptic fields. In a mechanistically similar fashion, homophilic repulsion mediated by Drosophila Dscam2 prevents processes from the same class of cells from occupying overlapping s... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1860418 Wed, 08 Oct 2008 19:00:34 +0100 1860418 http://www.medworm.com/index.php?rid=1635841&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18631099%26dopt%3DAbstract Authors: Inoué S This Perspective is an account of my early experience while I studied the dynamic organization and behavior of the mitotic spindle and its submicroscopic filaments using polarized light microscopy. The birefringence of spindle filaments in normally dividing plant and animal cells, and those treated by various agents, revealed (a) the reality of spindle fibers and fibrils in healthy living cells; (b) the labile, dynamic nature of the molecular filaments making up the spindle fibers; (c) the mode of fibrogenesis and action of orienting centers; and (d) force-generating properties based on the disassembly and assembly of the fibrils. These studies, which were carried out directly on living cells using improved polarizing microscopes, in fact predicted the reversible ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1635841 Wed, 16 Jul 2008 04:00:00 +0100 1635841 http://www.medworm.com/index.php?rid=1635840&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18631113%26dopt%3DAbstract Authors: Mockaitis K, Estelle M The plant hormone auxin, in particular indole-3-acetic acid (IAA), is a key regulator of virtually every aspect of plant growth and development. Auxin regulates transcription by rapidly modulating levels of Aux/IAA proteins throughout development. Recent studies demonstrate that auxin perception occurs through a novel mechanism. Auxin binds to TIR1, the F-box subunit of the ubiquitin ligase complex SCF(TIR1), and stabilizes the interaction between TIR1 and Aux/IAA substrates. This interaction results in Aux/IAA ubiquitination and subsequent degradation. Regulation of the Aux/IAA protein family by TIR1 and TIR1-like auxin receptors (AFBs) links auxin action to transcriptional regulation and provides a model by which the vast array of auxin influences on d... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1635840 Wed, 16 Jul 2008 04:00:00 +0100 1635840 http://www.medworm.com/index.php?rid=1617243&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616423%26dopt%3DAbstract Authors: Cohen S, Greenberg ME Sensory experience is critical for the proper development and plasticity of the brain throughout life. Successful adaptation to the environment is necessary for the survival of an organism, and this process requires the translation of specific sensory stimuli into changes in the structure and function of relevant neural circuits. Sensory-evoked activity drives synaptic input onto neurons within these behavioral circuits, initiating membrane depolarization and calcium influx into the cytoplasm. Calcium signaling triggers the molecular mechanisms underlying neuronal adaptation, including the activity-dependent transcriptional programs that drive the synthesis of the effector molecules required for long-term changes in neuronal function. Insight into the sig... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617243 Thu, 10 Jul 2008 04:00:00 +0100 1617243 http://www.medworm.com/index.php?rid=1617242&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616424%26dopt%3DAbstract Authors: Steinkraus KA, Kaeberlein M, Kennedy B Progress in aging research is now rapid, and surprisingly, studies in a single-celled eukaryote are a driving force. The genetic modulators of replicative life span in yeast are being identified, the molecular events that accompany aging are being discovered, and the extent to which longevity pathways are conserved between yeast and multicellular eukaryotes is being tested. In this review, we provide a brief retrospective view on the development of yeast as a model for aging and then turn to recent discoveries that have pushed aging research into novel directions and also linked aging in yeast to well-developed hypotheses in mammals. Although the question of what causes aging still cannot be answered definitively, that day may be rapidly ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617242 Thu, 10 Jul 2008 04:00:00 +0100 1617242 http://www.medworm.com/index.php?rid=1617241&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616425%26dopt%3DAbstract Authors: Long TA, Brady SM, Benfey PN Complex gene regulatory networks are composed of genes, noncoding RNAs, proteins, metabolites, and signaling components. The availability of genome-wide mutagenesis libraries; large-scale transcriptome, proteome, and metabalome data sets; and new high-throughput methods that uncover protein interactions underscores the need for mathematical modeling techniques that better enable scientists to synthesize these large amounts of information and to understand the properties of these biological systems. Systems biology approaches can allow researchers to move beyond a reductionist approach and to both integrate and comprehend the interactions of multiple components within these systems. Descriptive and mathematical models for gene regulatory networks ca... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617241 Thu, 10 Jul 2008 04:00:00 +0100 1617241 http://www.medworm.com/index.php?rid=1617240&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616426%26dopt%3DAbstract Authors: McStay B, Grummt I In eukaryotes, the genes encoding ribosomal RNAs (rDNA) exist in two distinct epigenetic states that can be distinguished by a specific chromatin structure that is maintained throughout the cell cycle and is inherited from one cell to another. The fact that even in proliferating cells with a high demand of protein synthesis a fraction of rDNA is silenced provides a unique possibility to decipher the mechanism underlying epigenetic regulation of rDNA. This chapter summarizes our knowledge of the molecular mechanisms that establish and propagate the epigenetic state of rRNA genes, unraveling a complex interplay of DNA methyltransferases and histone-modifying enzymes that act in concert with chromatin remodeling complexes and RNA-guided mechanisms to define the... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617240 Thu, 10 Jul 2008 04:00:00 +0100 1617240 http://www.medworm.com/index.php?rid=1617239&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616427%26dopt%3DAbstract Authors: Onn I, Heidinger-Pauli JM, Guacci V, Unal E, Koshland DE In eukaryotes, the process of sister chromatid cohesion holds the two sister chromatids (the replicated chromosomes) together from DNA replication to the onset of chromosome segregation. Cohesion is mediated by cohesin, a four-subunit SMC (structural maintenance of chromosome) complex. Cohesin and cohesion are required for proper chromosome segregation, DNA repair, and gene expression. To carry out these functions, cohesion is regulated by elaborate mechanisms involving a growing list of cohesin auxiliary factors. These factors control the timing and position of cohesin binding to chromatin, activate chromatin-bound cohesin to become cohesive, and orchestrate the orderly dissolution of cohesion. The 45-nm ring-like archi... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617239 Thu, 10 Jul 2008 04:00:00 +0100 1617239 http://www.medworm.com/index.php?rid=1617238&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18616428%26dopt%3DAbstract Authors: Rawn SM, Cross JC A number of placenta-specific genes (e.g., Tpbp, Plac1, Syncytin, and retrotransposon-associated genes such as Peg10, Rtl1, Endothelin B receptor, Insl4, Leptin, Midline1, and Pleiotrophin), enhancer elements (e.g., glycoprotein hormone alpha-subunit) and gene isoforms (e.g., 3betaHSD, Cyp19), as well as placenta-specific members of gene families (e.g., Gcm1, Mash2, Rhox, Esx1, Cathepsin, PAG, TKDP, Psg, Siglec) have been identified. This review summarizes their evolution, regulation, and biochemical functions and discusses their significance for placental development and function. Strikingly, the number of unique, truly placenta-specific genes that have been discovered to date is very small. The vast majority of placenta-specific gene products have resulted ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1617238 Thu, 10 Jul 2008 04:00:00 +0100 1617238 http://www.medworm.com/index.php?rid=1584183&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18598212%26dopt%3DAbstract Authors: Brockes JP, Kumar A Most but not all phyla include examples of species that are able to regenerate large sections of the body plan. The mechanisms underlying regeneration on this scale are currently being studied in a variety of contexts in both vertebrates and invertebrates. Regeneration generally involves the formation of a wound epithelium after transection or injury, followed by the generation of regenerative progenitor cells and morphogenesis to give the regenerate. Common mechanisms may exist in relation to each of these aspects. For example, the initial proliferation of progenitor cells often depends on the nerve supply, whereas morphogenesis reflects the generation of positional disparity between adjacent cells-the principle of intercalation. These mechanisms are revie... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584183 Thu, 03 Jul 2008 04:00:00 +0100 1584183 http://www.medworm.com/index.php?rid=1584182&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18598213%26dopt%3DAbstract Authors: Dustin ML The immunological synapse was initially defined as a stable cell-cell junction composed of three concentric supramolecular activation clusters (SMACs) enriched in particular components: a central SMAC with clustered antigen receptors and kinases, a peripheral SMAC rich in beta2 integrin adhesion molecule LFA-1, and a distal SMAC marked by a critical tyrosine phosphatase. In the past year the SMACs have each been identified with functional modules of amoeboid motility, and the stability of the immunological synapse has been revealed as a reconfiguration of the motile apparatus from an asymmetric hunting mode, a kinapse, to a symmetric gathering mode, the synapse. The genetic control of this process involves actinomyosin regulators PKCtheta and WASp. Crtam is involved ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584182 Thu, 03 Jul 2008 04:00:00 +0100 1584182 http://www.medworm.com/index.php?rid=1584181&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18598214%26dopt%3DAbstract Authors: Pesin JA, Orr-Weaver TL The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit E3 ubiquitin ligase that triggers the degradation of multiple substrates during mitosis. Cdc20/Fizzy and Cdh1/Fizzy-related activate the APC/C and confer substrate specificity through complex interactions with both the core APC/C and substrate proteins. The regulation of Cdc20 and Cdh1 is critical for proper APC/C activity and occurs in multiple ways: targeted protein degradation, phosphorylation, and direct binding of inhibitory proteins. During the specialized divisions of meiosis, the activity of the APC/C must be modified to achieve proper chromosome segregation. Recent studies show that one way in which APC/C activity is modified is through the use of meiosis-specific APC/C activato... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584181 Thu, 03 Jul 2008 04:00:00 +0100 1584181 http://www.medworm.com/index.php?rid=1584180&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18598215%26dopt%3DAbstract Authors: Liberali P, Rämö P, Pelkmans L The field of endocytosis is in strong need of formal biophysical modeling and mathematical analysis. At the same time, endocytosis must be much better integrated into cellular physiology to understand the former's complex behavior in such a wide range of phenotypic variations. Furthermore, the concept that endocytosis provides the space-time for signal transduction can now be experimentally addressed. In this review, we discuss these principles and argue for a systematic and top-down approach to study the endocytic membrane system. We provide a summary of published observations on protein kinases regulating endocytic machinery components and discuss global unbiased approaches to further map out kinase regulatory networks. In particular,... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584180 Thu, 03 Jul 2008 04:00:00 +0100 1584180 http://www.medworm.com/index.php?rid=1584184&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18597662%26dopt%3DAbstract Authors: Bhalla N, Dernburg AF Accurate segregation of chromosomes during meiosis requires physical links between homologs. These links are usually established through chromosome pairing, synapsis, and recombination, which occur during meiotic prophase. How chromosomes pair with their homologous partners is one of the outstanding mysteries of meiosis. Surprisingly, experimental evidence indicates that different organisms have found more than one way to accomplish this feat. Whereas some species depend on recombination machinery to achieve homologous pairing, others are able to pair and synapse their homologs in the absence of recombination. To ensure specific pairing between homologous chromosomes, both recombination-dependent and recombination-independent mechanisms must strike the pr... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584184 Wed, 02 Jul 2008 04:00:00 +0100 1584184 http://www.medworm.com/index.php?rid=1584187&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18593352%26dopt%3DAbstract Authors: Protas ME, Patel NH There is an amazing amount of diversity in coloration patterns in nature. The ease of observing this diversity and the recent application of genetic and molecular techniques to model and nonmodel animals are allowing us to investigate the genetic basis and evolution of coloration in an ever-increasing variety of animals. It is now possible to ask questions about how many genes are responsible for any given pattern, what types of genetic changes have occurred to generate the diversity, and if the same underlying genetic changes occur repeatedly when coloration phenotypes arise through convergent evolution or parallel evolution. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 24 is October 06, 2008. Please... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584187 Tue, 01 Jul 2008 04:00:00 +0100 1584187 http://www.medworm.com/index.php?rid=1584186&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18593353%26dopt%3DAbstract Authors: Takai Y, Ikeda W, Ogita H, Rikitake Y Nectins are immunoglobulin-like cell adhesion molecules (CAMs) that compose a family of four members. Nectins homophilically and heterophilically interact in trans with each other to form cell-cell adhesions. In addition, they heterophilically interact in trans with other immunoglobulin-like CAMs. Nectins bind afadin, an actin filament (F-actin)-binding protein, at its cytoplasmic tail and associate with the actin cytoskeleton. Afadin additionally serves as an adaptor protein by further binding many scaffolding proteins and F-actin-binding proteins and contributes to the association of nectins with other cell-cell adhesion and intracellular signaling systems. Nectins and afadin play roles in the formation of a variety of cell-cell junction... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584186 Tue, 01 Jul 2008 04:00:00 +0100 1584186 http://www.medworm.com/index.php?rid=1584185&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18593354%26dopt%3DAbstract We describe the events that have led to the discovery of the role of CD1 molecules, their pattern of intracellular trafficking, and their ability to sample different intracellular compartments for self- and foreign lipids. Structural and functional aspects of lipid presentation by CD1 molecules are presented in the context of the function of CD1-restricted T cells in antimicrobial responses, antitumor immunity, and the regulation of the tolerance and autoimmunity immunoregulatory axis. Particular emphasis is on invariant NKT (iNKT) cells and their ability to modulate innate and adaptive immune responses. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 24 is October 06, 2008. Please see http://www.annualreviews.org/catalog/pubdates.aspx ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584185 Tue, 01 Jul 2008 04:00:00 +0100 1584185 http://www.medworm.com/index.php?rid=1584188&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18590485%26dopt%3DAbstract Authors: Nickel W, Seedorf M The classical secretion of soluble proteins and transport of integral membrane proteins to the cell surface require transit into and through the endoplasmic reticulum and the Golgi apparatus. Signal peptides or transmembrane domains target proteins for translocation into the lumen or insertion into the membrane of the endoplasmic reticulum, respectively. Here we discuss two mechanisms of unconventional protein targeting to plasma membranes, i.e., transport processes that are active in the absence of a functional Golgi system. We first focus on integral membrane proteins that are inserted into the endoplasmic reticulum but that, however, are transported to plasma membranes in a Golgi-independent manner. We then discuss soluble secretory proteins that are sec... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584188 Fri, 27 Jun 2008 04:00:00 +0100 1584188 http://www.medworm.com/index.php?rid=1584191&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18588486%26dopt%3DAbstract Authors: Oatley JM, Brinster RL Mammalian spermatogenesis is a classic adult stem cell-dependent process, supported by self-renewal and differentiation of spermatogonial stem cells (SSCs). Studying SSCs provides a model to better understand adult stem cell biology, and deciphering the mechanisms that control SSC functions may lead to treatment of male infertility and an understanding of the etiology of testicular germ cell tumor formation. Self-renewal of rodent SSCs is greatly influenced by the niche factor glial cell line-derived neurotrophic factor (GDNF). In mouse SSCs, GDNF activation upregulates expression of the transcription factor-encoding genes bcl6b, etv5, and lhx1, which influence SSC self-renewal. Additionally, the non-GDNF-stimulated transcription factors Plzf and Taf4b h... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584191 Thu, 26 Jun 2008 04:00:00 +0100 1584191 http://www.medworm.com/index.php?rid=1584190&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18588487%26dopt%3DAbstract Authors: Mamathambika BS, Bardwell JC Determining the mechanism by which proteins attain their native structure is an important but difficult problem in basic biology. The study of protein folding is difficult because it involves the identification and characterization of folding intermediates that are only very transiently present. Disulfide bond formation is thermodynamically linked to protein folding. The availability of thiol trapping reagents and the relatively slow kinetics of disulfide bond formation have facilitated the isolation, purification, and characterization of disulfide-linked folding intermediates. As a result, the folding pathways of several disulfide-rich proteins are among the best known of any protein. This review discusses disulfide bond formation and its relation... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584190 Thu, 26 Jun 2008 04:00:00 +0100 1584190 http://www.medworm.com/index.php?rid=1584189&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18588488%26dopt%3DAbstract Authors: Jin Y, Garner CC Information processing in the nervous system relies on properly localized and organized synaptic structures at the correct locations. The formation of synapses is a long and intricate process involving multiple interrelated steps. Decades of research have identified a large number of molecular components of the presynaptic compartment. In addition to neurotransmitter-containing synaptic vesicles, presynaptic terminals are defined by cytoskeletal and membrane specializations that allow highly regulated exo- and endocytosis of synaptic vesicles and that maintain precise registration with postsynaptic targets. Functional studies at multiple levels have revealed complex interactions between the transport of vesicular intermediates, the presynaptic cytoskeleton, gr... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584189 Thu, 26 Jun 2008 04:00:00 +0100 1584189 http://www.medworm.com/index.php?rid=1584217&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17456018%26dopt%3DAbstract Authors: Tsai B Although the precise mechanism by which nonenveloped viruses penetrate biological membranes is unclear, a more coherent understanding of this process is starting to emerge. To initiate membrane penetration, nonenveloped viruses engage host cell factors that impart conformational changes on the viral particles, resulting in the exposure of a hydrophobic moiety or the release of a lytic factor. The viruses' interactions with the limiting membrane subsequently compromise the bilayer integrity. This reaction presumably perforates the bilayer to enable the virus to cross the membrane and reach the cytosol. Valuable insights into this process can be gleaned from the membrane transport mechanisms of enveloped viruses and bacterial toxins. To identify systematically the cellula... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584217 Mon, 01 Jan 2007 05:00:00 +0100 1584217 http://www.medworm.com/index.php?rid=1584216&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17456019%26dopt%3DAbstract We describe the morphological and molecular events that play a pivotal role in each of these four processes. PMID: 17456019 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584216 Mon, 01 Jan 2007 05:00:00 +0100 1584216 http://www.medworm.com/index.php?rid=1584215&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17474876%26dopt%3DAbstract Authors: Schäfer M, Werner S Injury to the skin initiates a complex process of events involving inflammation as well as the formation and remodeling of new tissue. These processes result in at least partial reconstitution of the injured skin. However, wounds in adult mammals heal with a scar, which is accompanied by functional and aesthetic impairments. In addition to this problem, a large number of patients, in particular in the aged population, suffer from chronic, nonhealing ulcers. Therefore, there is a strong need to improve the wound healing process. This requires a thorough understanding of the underlying molecular and cellular mechanisms. During the past several years, important regulators of the wound healing process have been identified. In particular, the growth factors... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584215 Mon, 01 Jan 2007 05:00:00 +0100 1584215 http://www.medworm.com/index.php?rid=1584214&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17489688%26dopt%3DAbstract Authors: Koster MI, Roop DR The epidermis is a stratified epithelium that functions as a barrier protecting the organism from dehydration, mechanical trauma, and microbial insults. This barrier function is established during embryogenesis through a complex and tightly controlled stratification program. Whereas the morphological changes that occur during epidermal development have been extensively studied, the molecular mechanisms that govern this process remain poorly understood. In this review we summarize the current advances that have been made in understanding the molecular mechanisms that regulate epidermal morphogenesis. PMID: 17489688 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584214 Mon, 01 Jan 2007 05:00:00 +0100 1584214 http://www.medworm.com/index.php?rid=1584213&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17489689%26dopt%3DAbstract Authors: Horwich AL, Fenton WA, Chapman E, Farr GW Chaperonins are large ring assemblies that assist protein folding to the native state by binding nonnative proteins in their central cavities and then, upon binding ATP, release the substrate protein into a now-encapsulated cavity to fold productively. Two families of such components have been identified: type I in mitochondria, chloroplasts, and the bacterial cytosol, which rely on a detachable "lid" structure for encapsulation, and type II in archaea and the eukaryotic cytosol, which contain a built-in protrusion structure. We discuss here a number of issues under current study. What is the range of substrates acted on by the two classes of chaperonin, in particular by GroEL in the bacterial cytoplasm and CCT in the eukaryotic cytoso... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584213 Mon, 01 Jan 2007 05:00:00 +0100 1584213 http://www.medworm.com/index.php?rid=1584212&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506688%26dopt%3DAbstract Authors: Sillitoe RV, Joyner AL The most noticeable morphological feature of the cerebellum is its folded appearance, whereby fissures separate its anterior-posterior extent into lobules. Each lobule is molecularly coded along the medial-lateral axis by parasagittal stripes of gene expression in one cell type, the Purkinje cells (PCs). Additionally, within each lobule distinct combinations of afferents terminate and supply the cerebellum with synchronized sensory and motor information. Strikingly, afferent terminal fields are organized into parasagittal domains, and this pattern bears a close relationship to PC molecular coding. Thus, cerebellum three-dimensional complexity obeys a basic coordinate system that can be broken down into morphology and molecular coding. In this review, we ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584212 Mon, 01 Jan 2007 05:00:00 +0100 1584212 http://www.medworm.com/index.php?rid=1584211&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506689%26dopt%3DAbstract We present our current understanding of different aspects of Pax3/7 function in myogenesis, focusing on the mouse model. This is compared with that of other Pax proteins in the emergence of tissue specific lineages and their differentiation as well as in cell survival, proliferation, and migration. Finally, we consider the molecular mechanisms that underlie the function of Pax transcription factors, including the cofactors and regulatory networks with which they interact. PMID: 17506689 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584211 Mon, 01 Jan 2007 05:00:00 +0100 1584211 http://www.medworm.com/index.php?rid=1584210&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506690%26dopt%3DAbstract Authors: Jiang D, Liang J, Noble PW A hallmark of tissue injury and repair is the turnover of extracellular matrix components. This review focuses on the role of the glycosaminoglycan hyaluronan in tissue injury and repair. Both the synthesis and degradation of extracellular matrix are critical contributors to tissue repair and remodeling. Fragmented hyaluronan accumulates during tissue injury and functions in ways distinct from the native polymer. There is accumulating evidence that hyaluronan degradation products can stimulate the expression of inflammatory genes by a variety of immune cells at the injury site. CD44 is the major cell-surface hyaluronan receptor and is required to clear hyaluronan degradation products produced during lung injury; impaired clearance of hyaluronan resul... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584210 Mon, 01 Jan 2007 05:00:00 +0100 1584210 http://www.medworm.com/index.php?rid=1584209&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506691%26dopt%3DAbstract Authors: Eggenschwiler JT, Anderson KV Recent studies have revealed unexpected connections between the mammalian Hedgehog (Hh) signal transduction pathway and the primary cilium, a microtubule-based organelle that protrudes from the surface of most vertebrate cells. Intraflagellar transport proteins, which are required for the construction of cilia, are essential for all responses to mammalian Hh proteins, and proteins required for Hh signal transduction are enriched in primary cilia. The phenotypes of different mouse mutants that affect ciliary proteins suggest that cilia may act as processive machines that organize sequential steps in the Hh signal transduction pathway. Cilia on vertebrate cells are likely to be important in additional developmental signaling pathways and are require... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584209 Mon, 01 Jan 2007 05:00:00 +0100 1584209 http://www.medworm.com/index.php?rid=1584207&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506693%26dopt%3DAbstract Authors: Ciofani M, Zúñiga-Pflücker JC Like all hematopoietic cells, T lymphocytes are derived from bone-marrow-resident stem cells. However, whereas most blood lineages are generated within the marrow, the majority of T cell development occurs in a specialized organ, the thymus. This distinction underscores the unique capacity of the thymic microenvironment to support T lineage restriction and differentiation. Although the identity of many of the contributing thymus-derived signals is well established and rooted in highly conserved pathways involving Notch, morphogenetic, and protein tyrosine kinase signals, the manner in which the ensuing cascades are integrated to orchestrate the underlying processes of T cell development remains under investigation. This review focus... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584207 Mon, 01 Jan 2007 05:00:00 +0100 1584207 http://www.medworm.com/index.php?rid=1584206&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506694%26dopt%3DAbstract Authors: Lipka V, Kwon C, Panstruga R In yeast and animal cells, members of the superfamily of N-ethylmaleimide-sensitive factor adaptor protein receptor (SNARE)-domain-containing proteins are key players in vesicle-associated membrane fusion events during transport processes between individual compartments of the endomembrane system, including exocytosis and endocytosis. Compared with genomes of other eukaryotes, genomes of monocotyledonous and dicotyledonous plants encode a surprisingly high number of SNARE proteins, suggesting vital roles for this protein class in higher plant species. Although to date it remains elusive whether plant SNARE proteins function like their yeast and animal counterparts, genetic screens have recently begun to unravel the variety of biological tasks in wh... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584206 Mon, 01 Jan 2007 05:00:00 +0100 1584206 http://www.medworm.com/index.php?rid=1584205&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506695%26dopt%3DAbstract Authors: Bushati N, Cohen SM microRNAs (miRNAs) are small noncoding RNAs that play important roles in posttranscriptional gene regulation. In animal cells, miRNAs regulate their targets by translational inhibition and mRNA destabilization. Here, we review recent work in animal models that provide insight into the diverse roles of miRNAs in vivo. PMID: 17506695 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584205 Mon, 01 Jan 2007 05:00:00 +0100 1584205 http://www.medworm.com/index.php?rid=1584204&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506696%26dopt%3DAbstract Authors: Pardue ML I have been fascinated by chromosomes for longer than I care to mention; their beautiful structure, cell-type-specific changes in morphology, and elegant movements delight me. Shortly before I began graduate study, the development of nucleic acid hybridization made it possible to compare two nucleic acids whether or not their sequences were known. From this stemmed a progression of development in tools and techniques that continues to enhance our understanding of how chromosomes function. As my PhD project I contributed to this progression by developing in situ hybridization, a technique for hybridization to nucleic acids within their cellular context. Early studies with this technique initiated several lines of research, two of which I describe here, that I have pur... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584204 Mon, 01 Jan 2007 05:00:00 +0100 1584204 http://www.medworm.com/index.php?rid=1584203&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506697%26dopt%3DAbstract Authors: Piper RC, Katzmann DJ The two major cellular sites for membrane protein degradation are the proteasome and the lysosome. Ubiquitin attachment is a sorting signal for both degradation routes. For lysosomal degradation, ubiquitination triggers the sorting of cargo proteins into the lumen of late endosomal multivesicular bodies (MVBs)/endosomes. MVB formation occurs when a portion of the limiting membrane of an endosome invaginates and buds into its own lumen. Intralumenal vesicles are degraded when MVBs fuse to lysosomes. The proper delivery of proteins to the MVB interior relies on specific ubiquitination of cargo, recognition and sorting of ubiquitinated cargo to endosomal subdomains, and the formation and scission of cargo-filled intralumenal vesicles. Over the past five year... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584203 Mon, 01 Jan 2007 05:00:00 +0100 1584203 http://www.medworm.com/index.php?rid=1584202&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506698%26dopt%3DAbstract Authors: Kimble J, Crittenden SL The Caenorhabditis elegans germ line provides an exceptional model for analysis of the molecular controls governing stem cell maintenance, the cell cycle transition from mitosis to meiosis, and the choice of sexual identity-sperm or oocyte. Germline stem cells are maintained in an undifferentiated state within a well-defined niche formed by a single somatic cell, the distal tip cell (DTC). In both sexes, the DTC employs GLP-1/Notch signaling and FBF/PUF RNA-binding proteins to maintain stem cells and promote mitotic divisions, three additional RNA regulators (GLD-1/quaking, GLD-2/poly(A) polymerase, and GLD-3/Bicaudal-C) control entry into meiosis, and FOG-1/CPEB and FOG-3/Tob proteins govern sperm specification. These key regulators are part of a robus... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584202 Mon, 01 Jan 2007 05:00:00 +0100 1584202 http://www.medworm.com/index.php?rid=1584201&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506699%26dopt%3DAbstract Authors: Shepherd JD, Huganir RL The cellular processes that govern neuronal function are highly complex, with many basic cell biological pathways uniquely adapted to perform the elaborate information processing achieved by the brain. This is particularly evident in the trafficking and regulation of membrane proteins to and from synapses, which can be a long distance away from the cell body and number in the thousands. The regulation of neurotransmitter receptors, such as the AMPA-type glutamate receptors (AMPARs), the major excitatory neurotransmitter receptors in the brain, is a crucial mechanism for the modulation of synaptic transmission. The levels of AMPARs at synapses are very dynamic, and it is these plastic changes in synaptic function that are thought to underlie information ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584201 Mon, 01 Jan 2007 05:00:00 +0100 1584201 http://www.medworm.com/index.php?rid=1584200&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506700%26dopt%3DAbstract Authors: Blair SS The positioning and elaboration of ectodermal veins in the wing of Drosophila melanogaster rely on widely utilized developmental signals, including those mediated by EGF, BMP, Hedgehog, Notch, and Wnt. Analysis of vein patterning mutants, using the molecular and genetic mosaic techniques available in Drosophila, has provided important insights into how a combination of short-range and long-range signaling can pattern a simple epidermal tissue. Moreover, venation has become a powerful system for isolating and analyzing novel components in these signaling pathways. I here review the basic events of vein patterning and give examples of how changes in venation have been used to identify important features of cell signaling pathways. PMID: 17506700 [PubMed - indexed fo... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584200 Mon, 01 Jan 2007 05:00:00 +0100 1584200 http://www.medworm.com/index.php?rid=1584199&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506701%26dopt%3DAbstract Authors: Stinchcombe JC, Griffiths GM Cytotoxic T lymphocytes (CTLs) play a critical role in the immune system; they are able to recognize and destroy virally infected and tumorigenic cells. Specific recognition of MHC class I-peptide complexes by the T cell receptor (TcR) results in precise delivery of lytic granules to the target cell, sparing neighboring cells and the CTL itself. Over the past 10 years various studies have eludicated the mechanisms that lead to the rapid polarization of the secretory apparatus in CTLs. These studies highlight similarities and differences between polarity and secretory mechanisms seen in other cell types and developmental systems. This review focuses on recent advances in our understanding of the molecular basis of polarized secretion from CTLs and t... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584199 Mon, 01 Jan 2007 05:00:00 +0100 1584199 http://www.medworm.com/index.php?rid=1584198&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506702%26dopt%3DAbstract Authors: Fagarasanu A, Fagarasanu M, Rachubinski RA Eukaryotic cells divide their metabolic labor between functionally distinct, membrane-enveloped organelles, each precisely tailored for a specific set of biochemical reactions. Peroxisomes are ubiquitous, endoplasmic reticulum-derived organelles that perform requisite biochemical functions intimately connected to lipid metabolism. Upon cell division, cells have to strictly control peroxisome division and inheritance to maintain an appropriate number of peroxisomes in each cell. Peroxisome division follows a specific sequence of events that include peroxisome elongation, membrane constriction, and peroxisome fission. Pex11 proteins mediate the elongation step of peroxisome division, whereas dynamin-related proteins execute the final fi... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584198 Mon, 01 Jan 2007 05:00:00 +0100 1584198 http://www.medworm.com/index.php?rid=1584197&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506703%26dopt%3DAbstract Authors: Gillingham AK, Munro S Small G proteins play a central role in the organization of the secretory and endocytic pathways. The majority of such small G proteins are members of the Rab family, which are anchored to the bilayer by C-terminal prenyl groups. However, the recruitment of some effectors, including vesicle coat proteins, is mediated by a second class of small G proteins that is unique in having an N-terminal amphipathic helix that becomes available for membrane insertion upon GTP binding. Sar1, Arf1, and Arf6 are the best-characterized members of this ADP-ribosylation factor (Arf) family. In addition, all eukaryotes contain additional distantly related G proteins, often called Arf like, or Arls. The complete Arf family in humans has 29 members. The roles of these relate... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584197 Mon, 01 Jan 2007 05:00:00 +0100 1584197 http://www.medworm.com/index.php?rid=1584196&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17539752%26dopt%3DAbstract Authors: Pokutta S, Weis WI Cadherins are Ca(2+)-dependent cell adhesion molecules found in several kinds of cell-cell contact, including adherens junctions and desmosomes. In the presence of Ca(2+), cells expressing the same type of cadherin form stable contacts with one another, a phenomenon designated homophilic, or homotypic, adhesion. Most cadherins are single-pass transmembrane proteins whose extracellular regions mediate specific cell-cell interactions. The intracellular faces of these contacts are associated with the actin cytoskeleton in adherens junctions or the intermediate-filament system in desmosomes. The close coordination of the transmembrane adhesion molecules with the cytoskeleton is believed to be essential in coordinating morphogenetic movements of tissues during de... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584196 Mon, 01 Jan 2007 05:00:00 +0100 1584196 http://www.medworm.com/index.php?rid=1584195&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17539753%26dopt%3DAbstract Authors: Tran TS, Kolodkin AL, Bharadwaj R Semaphorin proteins, although initially characterized as repulsive neuronal guidance cues, are now appreciated as major contributors to morphogenesis and homeostasis for a wide range of tissue types. Semaphorin-mediated long- and short-range repulsive, and attractive, guidance has profound influences on cellular morphology. The diversity of semaphorin receptor complexes utilized by various semaphorin ligands, the ability of semaphorins themselves to serve as receptors, and the myriad of intracellular signaling components that comprise semaphorin signaling cascades all contribute to cell-type-specific responses to semaphorins. Analysis of the molecular and cellular mechanisms underlying semaphorin function in neural and vascular systems provide... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584195 Mon, 01 Jan 2007 05:00:00 +0100 1584195 http://www.medworm.com/index.php?rid=1584194&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17539754%26dopt%3DAbstract Authors: Jenik PD, Gillmor CS, Lukowitz W Early embryonic development in the flowering plant Arabidopsis thaliana follows a predictable sequence of cell divisions. Anatomical hallmarks and the expression of marker genes in dynamic patterns indicate that new cell fates are established with virtually every round of mitosis. Although some of the factors regulating these early patterning events have been identified, the overall process remains relatively poorly understood. Starting at the globular stage, when the embryo has approximately 100 cells, the organization of development appears to be taken over by programs that regulate postembryonic patterning throughout the life cycle. PMID: 17539754 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584194 Mon, 01 Jan 2007 05:00:00 +0100 1584194 http://www.medworm.com/index.php?rid=1584193&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17645413%26dopt%3DAbstract Authors: Lobo NA, Shimono Y, Qian D, Clarke MF Cancers originally develop from normal cells that gain the ability to proliferate aberrantly and eventually turn malignant. These cancerous cells then grow clonally into tumors and eventually have the potential to metastasize. A central question in cancer biology is, which cells can be transformed to form tumors? Recent studies elucidated the presence of cancer stem cells that have the exclusive ability to regenerate tumors. These cancer stem cells share many characteristics with normal stem cells, including self-renewal and differentiation. With the growing evidence that cancer stem cells exist in a wide array of tumors, it is becoming increasingly important to understand the molecular mechanisms that regulate self-renewal and differentia... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584193 Mon, 01 Jan 2007 05:00:00 +0100 1584193 http://www.medworm.com/index.php?rid=1584192&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17944572%26dopt%3DAbstract Authors: Zheng JQ, Poo MM Neuronal motility is a fundamental feature that underlies the development, regeneration, and plasticity of the nervous system. Two major developmental events--directed migration of neuronal precursor cells to the proper positions and guided elongation of axons to their target cells--depend on large-scale neuronal motility. At a finer scale, motility is also manifested in many aspects of neuronal structures and functions, ranging from differentiation and refinement of axonal and dendritic morphology during development to synapse remodeling associated with learning and memory in the adult brain. As a primary second messenger that conveys the cytoplasmic actions of electrical activity and many neuroactive ligands, Ca(2+) plays a central role in the regulation of ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584192 Mon, 01 Jan 2007 05:00:00 +0100 1584192 http://www.medworm.com/index.php?rid=1584208&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17506692%26dopt%3DAbstract Authors: Poo MM, Zheng J Neuronal motility is a fundamental feature of the nervous system that underlies its development, regeneration and plasticity. Two major developmental events-directed migration of neuronal precursor cells to the proper positions and guided elongation of axons to their target cells-depend on large-scale neuronal motility. At a finer scale, motility is also manifested in many aspects of neuronal structures and functions, ranging from differentiation and refinement of axonal and dendritic morphology during development to synapse remodeling associated with learning and memory in the adult brain. As a primary second messenger that conveys the cytoplasmic actions of electrical activity and many neuroactive ligands, Ca(2+) plays a central role in the regulation of neur... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584208 Fri, 08 Sep 2006 04:00:00 +0100 1584208 http://www.medworm.com/index.php?rid=1584244&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704336%26dopt%3DAbstract Authors: Chan DC Eukaryotic cells maintain the overall shape of their mitochondria by balancing the opposing processes of mitochondrial fusion and fission. Unbalanced fission leads to mitochondrial fragmentation, and unbalanced fusion leads to mitochondrial elongation. Moreover, these processes control not only the shape but also the function of mitochondria. Mitochondrial dynamics allows mitochondria to interact with each other; without such dynamics, the mitochondrial population consists of autonomous organelles that have impaired function. Key components of the mitochondrial fusion and fission machinery have been identified, allowing initial dissection of their mechanisms of action. These components play important roles in mitochondrial function and development as well as programmed... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584244 Sun, 01 Jan 2006 05:00:00 +0100 1584244 http://www.medworm.com/index.php?rid=1584243&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704337%26dopt%3DAbstract Authors: Gurdon JB This is a personal historical account of events leading from the earliest success in vertebrate nuclear transfer to the current hope that nuclear reprogramming may facilitate cell replacement therapy. Early morphological evidence in Amphibia for the toti- or multipotentiality of some nuclei from differentiated cells first established the principle of the conservation of the genome during cell differentiation. Molecular markers show that many somatic cell nuclei are reprogrammed to an embryonic pattern of gene expression soon after nuclear transplantation to eggs. The germinal vesicles of oocytes in first meiotic prophase have a direct reprogramming activity on mammalian as well as amphibian nuclei and offer a route to identify nuclear reprogramming molecules. Amphibi... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584243 Sun, 01 Jan 2006 05:00:00 +0100 1584243 http://www.medworm.com/index.php?rid=1584242&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16704338%26dopt%3DAbstract Authors: Tombola F, Pathak MM, Isacoff EY Neurons transmit information through electrical signals generated by voltage-gated ion channels. These channels consist of a large superfamily of proteins that form channels selective for potassium, sodium, or calcium ions. In this review we focus on the molecular mechanisms by which these channels convert changes in membrane voltage into the opening and closing of "gates" that turn ion conductance on and off. An explosion of new studies in the last year, including the first X-ray crystal structure of a mammalian voltage-gated potassium channel, has led to radically different interpretations of the structure and molecular motion of the voltage sensor. The interpretations are as distinct as the techniques employed for the studies: crystallograph... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584242 Sun, 01 Jan 2006 05:00:00 +0100 1584242 http://www.medworm.com/index.php?rid=1584241&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16709150%26dopt%3DAbstract Authors: McCullen CA, Binns AN Host recognition and macromolecular transfer of virulence-mediating effectors represent critical steps in the successful transformation of plant cells by Agrobacterium tumefaciens. This review focuses on bacterial and plant-encoded components that interact to mediate these two processes. First, we examine the means by which Agrobacterium recognizes the host, via both diffusible plant-derived chemicals and cell-cell contact, with emphasis on the mechanisms by which multiple host signals are recognized and activate the virulence process. Second, we characterize the recognition and transfer of protein and protein-DNA complexes through the bacterial and plant cell membrane and wall barriers, emphasizing the central role of a type IV secretion system-the VirB ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584241 Sun, 01 Jan 2006 05:00:00 +0100 1584241 http://www.medworm.com/index.php?rid=1584240&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753028%26dopt%3DAbstract Authors: Kerscher O, Felberbaum R, Hochstrasser M Following the discovery of protein modification by the small, highly conserved ubiquitin polypeptide, a number of distinct ubiquitin-like proteins (Ubls) have been found to function as protein modifiers as well. These Ubls, which include SUMO, ISG15, Nedd8, and Atg8, function as critical regulators of many cellular processes, including transcription, DNA repair, signal transduction, autophagy, and cell-cycle control. A growing body of data also implicates the dysregulation of Ubl-substrate modification and mutations in the Ubl-conjugation machinery in the etiology and progression of a number of human diseases. The primary aim of this review is to summarize the latest developments in our understanding of the different Ubl-protein modific... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584240 Sun, 01 Jan 2006 05:00:00 +0100 1584240 http://www.medworm.com/index.php?rid=1584239&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16753029%26dopt%3DAbstract Authors: Chang TY, Chang CC, Ohgami N, Yamauchi Y Mammalian cells acquire cholesterol from low-density lipoprotein (LDL) and from endogenous biosynthesis. The roles of the Niemann-Pick type C1 protein in mediating the endosomal transport of LDL-derived cholesterol and endogenously synthesized cholesterol are discussed. Excess cellular cholesterol is converted to cholesteryl esters by the enzyme acyl-coenzyme A:cholesterol acyltransferase (ACAT) 1 or is removed from a cell by cellular cholesterol efflux at the plasma membrane. A close relationship between the ACAT substrate pool and the cholesterol efflux pool is proposed. Sterol-sensing domains (SSDs) are present in several membrane proteins, including NPC1, HMG-CoA reductase, and the SREBP cleavage-activating protein. The functions of... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584239 Sun, 01 Jan 2006 05:00:00 +0100 1584239 http://www.medworm.com/index.php?rid=1584238&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16771626%26dopt%3DAbstract Authors: Shin K, Fogg VC, Margolis B The tight junction is an intracellular junctional structure that mediates adhesion between epithelial cells and is required for epithelial cell function. Tight junctions control paracellular permeability across epithelial cell sheets and also serve as a barrier to intramembrane diffusion of components between a cell's apical and basolateral membrane domains. Recent genetic and biochemical studies in invertebrates and vertebrates indicate that tight junction proteins play an important role in the establishment and maintenance of apico-basal polarity. Proteins involved in epithelial cell polarization form evolutionarily conserved multiprotein complexes at the tight junction, and these protein complexes regulate the architecture of epithelia throughout... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584238 Sun, 01 Jan 2006 05:00:00 +0100 1584238 http://www.medworm.com/index.php?rid=1584237&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16774460%26dopt%3DAbstract Authors: Kunwar PS, Siekhaus DE, Lehmann R The basic concepts of the molecular machinery that mediates cell migration have been gleaned from cell culture systems. However, the three-dimensional environment within an organism presents migrating cells with a much greater challenge. They must move between and among other cells while interpreting multiple attractive and repulsive cues to choose their proper path. They must coordinate their cell adhesion with their surroundings and know when to start and stop moving. New insights into the control of these remaining mysteries have emerged from genetic dissection and live imaging of germ cell migration in Drosophila, zebrafish, and mouse embryos. In this review, we first describe germ cell migration in cellular and mechanistic detail in these... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584237 Sun, 01 Jan 2006 05:00:00 +0100 1584237 http://www.medworm.com/index.php?rid=1584236&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16776558%26dopt%3DAbstract Authors: Fischer JA, Eun SH, Doolan BT Endocytosis and endosome trafficking regulate cell signaling in unexpected ways. Here we review the contribution that Drosophila research has made to this exciting field. In addition to attenuating signaling, endocytosis shapes morphogen gradients, activates ligands, and regulates spatially receptor activation within a single cell. Moreover, some receptors signal from within endosomes, and the ability of a specific type of endosome to form controls the ability of cells to signal. Experiments in Drosophila reveal that through regulation of a variety of cell signaling pathways, endocytosis controls cell patterning and cell fate. PMID: 16776558 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584236 Sun, 01 Jan 2006 05:00:00 +0100 1584236 http://www.medworm.com/index.php?rid=1584235&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16803431%26dopt%3DAbstract Authors: Crane JF, Trainor PA Neural crest cells are a multipotent, migratory cell population that generates an astonishingly diverse array of cell types during vertebrate development. These include bones; tendons; neurons; glia; melanocytes; and connective, endocrine, and adipose tissue. With a limited capacity for self-renewal and a wide range of differentiation fates, neural crest cells bear many of the hallmarks of stem cells and persist throughout embryonic and adult development. But are all neural crest cells true stem cells, or do the majority of neural crest cells more closely resemble progenitor cells? In this review we discuss recent advances in characterizing the properties of neural crest cells, together with their potential for tissue-specific repair. PMID: 16803431 [P... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584235 Sun, 01 Jan 2006 05:00:00 +0100 1584235 http://www.medworm.com/index.php?rid=1584234&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16805665%26dopt%3DAbstract Authors: Bülow HE, Hobert O Proteoglycans (PGs), molecules in which glycosaminoglycans (GAGs) are covalently linked to a protein core, are components of the extracellular matrix of all multicellular organisms. Sugar moieties in GAGs are often extensively modified, which make these molecules enormously complex. We discuss here the role of PGs during animal development, emphasizing the in vivo significance of sugar modifications. We explore a model in which the modification patterns of GAG chains may provide a specific code that contributes to the correct development of a multicellular organism. PMID: 16805665 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584234 Sun, 01 Jan 2006 05:00:00 +0100 1584234 http://www.medworm.com/index.php?rid=1584233&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16822172%26dopt%3DAbstract Authors: Bernales S, Papa FR, Walter P The unfolded protein response (UPR) is an intracellular signaling pathway that is activated by the accumulation of unfolded proteins in the endoplasmic reticulum (ER). UPR activation triggers an extensive transcriptional response, which adjusts the ER protein folding capacity according to need. As such, the UPR constitutes a paradigm of an intracellular control mechanism that adjusts organelle abundance in response to environmental or developmental clues. The pathway involves activation of ER unfolded protein sensors that operate in parallel circuitries to transmit information across the ER membrane, activating a set of downstream transcription factors by mechanisms that are unusual yet rudimentarily conserved in all eukaryotes. Recent results she... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584233 Sun, 01 Jan 2006 05:00:00 +0100 1584233 http://www.medworm.com/index.php?rid=1584232&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16822173%26dopt%3DAbstract Authors: West AP, Koblansky AA, Ghosh S Toll-like receptors (TLRs) are transmembrane proteins that detect invading pathogens by binding conserved, microbially derived molecules and that induce signaling cascades for proinflammatory gene expression. A critical component of the innate immune system, TLRs utilize leucine-rich-repeat motifs for ligand binding and a shared cytoplasmic domain to recruit the adaptors MyD88, TRIF, TIRAP, and/or TRAM for downstream signaling. Despite significant domain conservation, TLRs induce gene programs that lead not only to the robust production of general proinflammatory mediators but also to the production of unique effectors, which provide pathogen-tailored immune responses. Here we review the mechanisms by which TLRs recognize pathogens and induce dis... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584232 Sun, 01 Jan 2006 05:00:00 +0100 1584232 http://www.medworm.com/index.php?rid=1584231&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16822174%26dopt%3DAbstract Authors: Dressler GR Mammalian kidney development has helped elucidate the general concepts of mesenchymal-epithelial interactions, inductive signaling, epithelial cell polarization, and branching morphogenesis. Through the use of genetically engineered mouse models, the manipulation of Xenopus and chick embryos, and the identification of human renal disease genes, the molecular bases for many of the early events in the developing kidney are becoming increasingly clear. Early patterning of the kidney region depends on interactions between Pax/Eya/Six genes, with essential roles for lim1 and Odd1. Ureteric bud outgrowth and branching morphogenesis are controlled by the Ret/Gdnf pathway, which is subject to positive and negative regulation by a variety of factors. A clear role for Wnt pr... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584231 Sun, 01 Jan 2006 05:00:00 +0100 1584231 http://www.medworm.com/index.php?rid=1584230&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824006%26dopt%3DAbstract Authors: Somerville C Cellulose microfibrils play essential roles in the organization of plant cell walls, thereby allowing a growth habit based on turgor. The fibrils are made by 30 nm diameter plasma membrane complexes composed of approximately 36 subunits representing at least three types of related CESA proteins. The complexes assemble in the Golgi, where they are inactive, and move to the plasma membrane, where they become activated. The complexes move through the plasma membrane during cellulose synthesis in directions that coincide with the orientation of microtubules. Recent, simultaneous, live-cell imaging of cellulose synthase and microtubules indicates that the microtubules exert a direct influence on the orientation of cellulose deposition. Genetic studies in Arabidopsis ha... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584230 Sun, 01 Jan 2006 05:00:00 +0100 1584230 http://www.medworm.com/index.php?rid=1584229&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824007%26dopt%3DAbstract We describe our current understanding of the TGN-to-cell-surface carriers, with a specific focus on the components involved in membrane fission. Inhibiting the fission machinery promotes growth of transport carriers into large tubules that remain attached to the TGN. Overactivating this machinery, on the other hand, vesiculates the TGN. To understand how membrane fission is regulated by cargo to form transport carriers yet prevents complete vesiculation of the TGN remains a daunting challenge. We discuss these issues with regard to TGN-to-cell-surface transport carriers. PMID: 16824007 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584229 Sun, 01 Jan 2006 05:00:00 +0100 1584229 http://www.medworm.com/index.php?rid=1584228&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824008%26dopt%3DAbstract Authors: Lill R, Mühlenhoff U Iron-sulfur (Fe/S) clusters require a complex set of proteins to become assembled and incorporated into apoproteins in a living cell. Researchers have described three distinct assembly systems in eukaryotes that are involved in the maturation of cellular Fe/S proteins. Mitochondria are central for biogenesis. They contain the ISC-the iron-sulfur cluster assembly machinery that was inherited from a similar system of eubacteria in evolution and is involved in biogenesis of all cellular Fe/S proteins. The basic principle of mitochondrial (and bacterial) Fe/S protein maturation is the synthesis of the Fe/S cluster on a scaffold protein before the cluster is transferred to apoproteins. Biogenesis of cytosolic and nuclear Fe/S proteins is facilitated by the... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584228 Sun, 01 Jan 2006 05:00:00 +0100 1584228 http://www.medworm.com/index.php?rid=1584227&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824009%26dopt%3DAbstract Authors: Martens S, Howard J Mammalian cells respond to interferons (IFNs) secreted during infection by the transcriptional upregulation of as many as a thousand genes. This remarkable transition prepares cells and organisms for resistance to infection, and many IFN-regulated gene products are players in well-understood resistance programs. Oddly, however, many of the most abundantly induced proteins are GTPases whose functions are not well understood. Here we review the progress that has been made toward understanding the roles of individual GTPase families in disease resistance and the hints of common mechanisms that are now available. PMID: 16824009 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584227 Sun, 01 Jan 2006 05:00:00 +0100 1584227 http://www.medworm.com/index.php?rid=1584226&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824012%26dopt%3DAbstract Authors: Blanpain C, Fuchs E The skin constantly renews itself throughout adult life, and the hair follicle undergoes a perpetual cycle of growth and degeneration. Stem cells (SCs) residing in the epidermis and hair follicle ensure the maintenance of adult skin homeostasis and hair regeneration, but they also participate in the repair of the epidermis after injuries. We summarize here the current knowledge of epidermal SCs of the adult skin. We discuss their fundamental characteristics, the methods recently designed to isolate these cells, the genes preferentially expressed in the multipotent SC niche, and the signaling pathways involved in SC niche formation, SC maintenance, and activation. Finally, we speculate on how the deregulation of these pathways may lead to cancer formation. ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584226 Sun, 01 Jan 2006 05:00:00 +0100 1584226 http://www.medworm.com/index.php?rid=1584225&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824013%26dopt%3DAbstract Authors: Aszódi A, Legate KR, Nakchbandi I, Fässler R For many years the extracellular matrix was viewed as a benign scaffold for arranging cells within connective tissues, but it is now being redefined as a dynamic, mobile, and flexible key player in defining cellular behavior. Gene targeting, transgene expression, and spontaneous mutations of extracellular matrix proteins in mice have greatly accelerated our mechanistic view of the structural and instructive functions of the extracellular matrix in developmental and regenerative processes. This review summarizes the phenotypes of genetic mouse models carrying mutations in extracellular matrix proteins, with specific emphasis on recent advances. The application of reverse genetics has demonstrated the multifunctionality of m... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584225 Sun, 01 Jan 2006 05:00:00 +0100 1584225 http://www.medworm.com/index.php?rid=1584224&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824014%26dopt%3DAbstract Authors: Hartenstein V Recent findings strongly suggest that the molecular pathways involved in the development and function of blood cells are highly conserved among vertebrates and various invertebrate phyla. This has led to a renewed interest regarding homologies between blood cell types and their developmental origin among different animals. One way to address these areas of inquiry is to shed more light on the biology of blood cells in extant invertebrate taxa that have branched off the bilaterian tree in between insects and vertebrates. This review attempts, in a broadly comparative manner, to update the existing literature that deals with early blood cell development. I begin by providing a brief survey of the different types of blood cell lineages among metazoa. There is now go... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584224 Sun, 01 Jan 2006 05:00:00 +0100 1584224 http://www.medworm.com/index.php?rid=1584223&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824015%26dopt%3DAbstract Authors: Heit JJ, Karnik SK, Kim SK Once thought incapable of significant proliferation, the pancreatic beta-cell has recently been shown to harbor immense powers of self-renewal. Pancreatic beta-cells, the sole source of insulin in vertebrate animals, can grow facultatively to a degree unmatched by other organs in experimental animals. beta-cell growth matches changes in systemic insulin demand, which increase during common physiologic states such as aging, obesity, and pregnancy. Compensatory changes in beta-cell mass are controlled by beta-cell proliferation. Here we review recent advances in our understanding of the intrinsic factors and mechanisms that control beta-cell cycle progression. Dysregulation of beta-cell proliferation is emerging as a fundamental feature in the pathogen... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584223 Sun, 01 Jan 2006 05:00:00 +0100 1584223 http://www.medworm.com/index.php?rid=1584222&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824016%26dopt%3DAbstract We describe the essential roles of context and organ structure in directing mammary gland development and differentiated function and in determining the response to oncogenic insults, including mutations. We expand on the concept of "dynamic reciprocity" to present an integrated view of development, cancer, and aging and posit that genes are like the keys on a piano: Although they are essential, it is the context that makes the music. PMID: 16824016 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584222 Sun, 01 Jan 2006 05:00:00 +0100 1584222 http://www.medworm.com/index.php?rid=1584221&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16824017%26dopt%3DAbstract Authors: Stewart SA, Weinberg RA The cell phenotypes of senescence and crisis operate to circumscribe the proliferative potential of mammalian cells, suggesting that both are capable of operating in vivo to suppress the formation of tumors. The key regulators of these phenotypes are the telomeres, which are located at the ends of chromosomes and operate to protect the chromosomes from end-to-end fusions. Telomere erosion below a certain length can trigger crisis. The relationship between senescence and telomere function is more complex, however: Cell-physiological stresses as well as dysfunction of the complex molecular structures at the ends of telomeric DNA can trigger senescence. Cells can escape senescence by inactivating the Rb and p53 tumor suppressor proteins and can surmount cr... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584221 Sun, 01 Jan 2006 05:00:00 +0100 1584221 http://www.medworm.com/index.php?rid=1584220&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16842034%26dopt%3DAbstract Authors: Hay BA, Guo M Cell death plays many roles during development, in the adult, and in the genesis of many pathological states. Much of this death is apoptotic in nature and requires the activity of members of the caspase family of proteases. It is now possible uniquely in Drosophila to carry out genetic screens for genes that determine the fate-life or death-of any population of cells during development and adulthood. This, in conjunction with the ability to obtain biochemical quantities of material, has made Drosophila a useful organism for exploring the mechanisms by which apoptosis is carried out and regulated. This review summarizes our knowledge of caspase-dependent cell death in Drosophila and compares that knowledge with what is known in worms and mammals. We also discuss ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584220 Sun, 01 Jan 2006 05:00:00 +0100 1584220 http://www.medworm.com/index.php?rid=1584219&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17029581%26dopt%3DAbstract Authors: Dickson BJ, Gilestro GF Commissural axons grow along complex pathways toward, across, and beyond the midline of the central nervous system. Taking commissural axons in the vertebrate spinal cord and the Drosophila ventral nerve cord as examples, we examine how commissural axon pathfinding is regulated by the Slit family of guidance cues and their Robo family receptors. We extract several principles that seem likely to apply to other axons and other contexts, such as the reiterative use of the same guidance molecules in distinct pathfinding decisions, the transcriptional specification of a pathway, the posttranscriptional regulation of growth along the pathway, and the possible role of feedback mechanisms to ensure the fidelity of pathfinding choices. Such mechanisms may help e... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584219 Sun, 01 Jan 2006 05:00:00 +0100 1584219 http://www.medworm.com/index.php?rid=1584218&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17029582%26dopt%3DAbstract Authors: Mombaerts P The main olfactory epithelium of the mouse is a mosaic of 2000 populations of olfactory sensory neurons (OSNs). Each population expresses one allele of one of the 1000 intact odorant receptor (OR) genes. An OSN projects a single unbranched axon to a single glomerulus, from an array of 1600-1800 glomeruli in the main olfactory bulb. Within a glomerulus the OSN axon synapses with the dendrites of second-order neurons and interneurons. Axons of OSNs that express the same OR project to the same glomeruli-typically one glomerulus per half-bulb and thus four glomeruli per mouse. These glomeruli are located at characteristic positions within the glomerular layer of the bulb. ORs determine both the odorant response profile of the OSN and the projection of its axon to a spe... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584218 Sun, 01 Jan 2006 05:00:00 +0100 1584218 http://www.medworm.com/index.php?rid=1584272&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212485%26dopt%3DAbstract Authors: Sabatini DD In this review I describe the several stages of my research career, all of which were driven by a desire to understand the basic mechanisms responsible for the complex and beautiful organization of the eukaryotic cell. I was originally trained as an electron microscopist in Argentina, and my first major contribution was the introduction of glutaraldehyde as a fixative that preserved the fine structure of cells, which opened the way for cytochemical studies at the EM level. My subsequent work on membrane-bound ribosomes illuminated the process of cotranslational translocation of polypeptides across the ER membrane and led to the formulation, with Gunter Blobel, of the signal hypothesis. My later studies with many talented colleagues contributed to an understanding o... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584272 Sat, 01 Jan 2005 05:00:00 +0100 1584272 http://www.medworm.com/index.php?rid=1584271&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212486%26dopt%3DAbstract Authors: Yan N, Shi Y Apoptosis plays a central role in the development and homeostasis of metazoans. Research in the past two decades has led to the identification of hundreds of genes that govern the initiation, execution, and regulation of apoptosis. An earlier focus on the genetic and cell biological characterization has now been complemented by systematic biochemical and structural investigation, giving rise to an unprecedented level of clarity in many aspects of apoptosis. In this review, we focus on the molecular mechanisms of apoptosis by synthesizing available biochemical and structural information. We discuss the mechanisms of ligand binding to death receptors, actions of the Bcl-2 family of proteins, and caspase activation, inhibition, and removal of inhibition. Although an ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584271 Sat, 01 Jan 2005 05:00:00 +0100 1584271 http://www.medworm.com/index.php?rid=1584270&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212487%26dopt%3DAbstract Authors: Niggli V Phosphoinositide phosphates (PIPs) correspond to phosphorylated derivatives of phosphatidylinositol (PI). Despite their relatively low abundance in the plasma membrane, PIPs play a crucial role as precursors of second messengers and are themselves important signaling and targeting molecules. Indeed, modulation of levels of PIPs affects, for example, cortical actin organization, membrane dynamics, and cell migration. The focus of this review is on selected interesting targets of PIPs. Those proteins that bind PIPs and are involved in regulation of actin assembly, actin membrane linkage, and actin contractility are discussed, as well as those that are involved in signaling, such as small GTPases, protein kinases, and phosphatases, or in regulation of membrane dynamics. ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584270 Sat, 01 Jan 2005 05:00:00 +0100 1584270 http://www.medworm.com/index.php?rid=1584269&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212488%26dopt%3DAbstract Authors: Kolter T, Sandhoff K Sphingolipids and glycosphingolipids are membrane components of eukaryotic cell surfaces. Their constitutive degradation takes place on the surface of intra-endosomal and intra-lysosomal membrane structures. During endocytosis, these intra-lysosomal membranes are formed and prepared for digestion by a lipid-sorting process during which their cholesterol content decreases and the concentration of the negatively charged bis(monoacylglycero)phosphate (BMP)--erroneously also called lysobisphosphatidic acid (LBPA)--increases. Glycosphingolipid degradation requires the presence of water-soluble acid exohydrolases, sphingolipid activator proteins, and anionic phospholipids like BMP. The lysosomal degradation of sphingolipids with short hydrophilic head groups req... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584269 Sat, 01 Jan 2005 05:00:00 +0100 1584269 http://www.medworm.com/index.php?rid=1584268&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212489%26dopt%3DAbstract Authors: Cioce M, Lamond AI This review surveys what is known about the structure and function of the subnuclear domains called Cajal bodies (CBs). The major focus is on CBs in mammalian cells but we provide an overview of homologous CB structures in other organisms. We discuss the protein and RNA components of CBs, including factors recently found to associate in a cell cycle-dependent fashion or under specific metabolic or stress conditions. We also consider the dynamic properties of both CBs and their molecular components, based largely on recent data obtained thanks to the advent of improved in vivo detection and imaging methods. We discuss how these data contribute to an understanding of CB functions and highlight major questions that remain to be answered. Finally, we consider th... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584268 Sat, 01 Jan 2005 05:00:00 +0100 1584268 http://www.medworm.com/index.php?rid=1584267&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212490%26dopt%3DAbstract Authors: Henikoff S, Ahmad K Chromatin can be differentiated by the deposition of variant histones at centromeres, active genes, and silent loci. Variant histones are assembled into nucleosomes in a replication-independent manner, in contrast to assembly of bulk chromatin that is coupled to replication. Recent in vitro studies have provided the first glimpses of protein machines dedicated to building and replacing alternative nucleosomes. They deposit variant H2A and H3 histones and are targeted to particular functional sites in the genome. Differences between variant and canonical histones can have profound consequences, either for delivery of the histones to sites of assembly or for their function after incorporation into chromatin. Recent studies have also revealed connections betwe... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584267 Sat, 01 Jan 2005 05:00:00 +0100 1584267 http://www.medworm.com/index.php?rid=1584266&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212491%26dopt%3DAbstract Authors: Klein TJ, Mlodzik M Polarization is a feature common to many cell types. Epithelial cells, for example, exhibit a characteristic apical-basolateral polarity that is critical for their function. In addition to this ubiquitous form of polarity, whole fields of cells are often polarized in a plane perpendicular to the apical-basal axis. This form of polarity, referred to as planar cell polarity (PCP), exists in all adult Drosophila cuticular tissues, as well as in numerous vertebrate tissues, including the mammalian skin and inner ear epithelia. Recent advances in the study of PCP establishment are beginning to unravel the molecular mechanisms underlying this cellular process. This review discusses new developments in the molecular understanding of PCP in Drosophila and vertebrat... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584266 Sat, 01 Jan 2005 05:00:00 +0100 1584266 http://www.medworm.com/index.php?rid=1584265&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212492%26dopt%3DAbstract Authors: Vert G, Nemhauser JL, Geldner N, Hong F, Chory J Brassinosteroids (BRs), the polyhydroxylated steroid hormones of plants, regulate the growth and differentiation of plants throughout their life cycle. Over the past several years, genetic and biochemical approaches have yielded great progress in understanding BR signaling. Unlike their animal counterparts, BRs are perceived at the plasma membrane by direct binding to the extracellular domain of the BRI1 receptor S/T kinase. BR perception initiates a signaling cascade, acting through a GSK3 kinase, BIN2, and the BSU1 phosphatase, which in turn modulates the phosphorylation state and stability of the nuclear transcription factors BES1 and BZR1. Microarray technology has been used extensively to provide a global view of BR genomic... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584265 Sat, 01 Jan 2005 05:00:00 +0100 1584265 http://www.medworm.com/index.php?rid=1584264&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212493%26dopt%3DAbstract Authors: Baskin TI Plants shape their organs with a precision demanded by optimal function; organ shaping requires control over cell wall expansion anisotropy. Focusing on multicellular organs, I survey the occurrence of expansion anisotropy and discuss its causes and proposed controls. Expansion anisotropy of a unit area of cell wall is characterized by the direction and degree of anisotropy. The direction of maximal expansion rate is usually regulated by the direction of net alignment among cellulose microfibrils, which overcomes the prevailing stress anisotropy. In some stems, the directionality of expansion of epidermal cells is controlled by that of the inner tissue. The degree of anisotropy can vary widely as a function of position and of treatment. The degree of anisotropy is pr... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584264 Sat, 01 Jan 2005 05:00:00 +0100 1584264 http://www.medworm.com/index.php?rid=1584263&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212494%26dopt%3DAbstract Authors: Kindler S, Wang H, Richter D, Tiedge H In eukaryotes, the entwined pathways of RNA transport and local translational regulation are key determinants in the spatio-temporal articulation of gene expression. One of the main advantages of this mechanism over transcriptional control in the nucleus lies in the fact that it endows local sites with independent decision-making authority, a consideration that is of particular relevance in cells with complex cellular architecture such as neurons. Localized RNAs typically contain codes, expressed within cis-acting elements, that specify subcellular targeting. Such codes are recognized by trans-acting factors, adaptors that mediate translocation along cytoskeletal elements by molecular motors. Most transported mRNAs are assumed translation... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584263 Sat, 01 Jan 2005 05:00:00 +0100 1584263 http://www.medworm.com/index.php?rid=1584262&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212495%26dopt%3DAbstract Authors: Jaffe AB, Hall A Approximately one percent of the human genome encodes proteins that either regulate or are regulated by direct interaction with members of the Rho family of small GTPases. Through a series of complex biochemical networks, these highly conserved molecular switches control some of the most fundamental processes of cell biology common to all eukaryotes, including morphogenesis, polarity, movement, and cell division. In the first part of this review, we present the best characterized of these biochemical pathways; in the second part, we attempt to integrate these molecular details into a biological context. PMID: 16212495 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584262 Sat, 01 Jan 2005 05:00:00 +0100 1584262 http://www.medworm.com/index.php?rid=1584261&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212496%26dopt%3DAbstract Authors: Smith LG, Oppenheimer DG The cytoskeleton plays important roles in plant cell shape determination by influencing the patterns in which cell wall materials are deposited. Cortical microtubules are thought to orient the direction of cell expansion primarily via their influence on the deposition of cellulose into the wall, although the precise nature of the microtubule-cellulose relationship remains unclear. In both tip-growing and diffusely growing cell types, F-actin promotes growth and also contributes to the spatial regulation of growth. F-actin has been proposed to play a variety of roles in the regulation of secretion in expanding cells, but its functions in cell growth control are not well understood. Recent work highlighted in this review on the morphogenesis of selected ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584261 Sat, 01 Jan 2005 05:00:00 +0100 1584261 http://www.medworm.com/index.php?rid=1584260&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212497%26dopt%3DAbstract Authors: Meins F, Si-Ammour A, Blevins T RNA silencing refers to a broad range of phenomena sharing the common feature that large, double-stranded RNAs or stem-loop precursors are processed to ca. 21-26 nucleotide small RNAs, which then guide the cleavage of cognate RNAs, block productive translation of these RNAs, or induce methylation of specific target DNAs. Although the core mechanisms are evolutionarily conserved, epigenetic maintenance of silencing by amplification of small RNAs and the elaboration of mobile, RNA-based silencing signals occur predominantly in plants. Plant RNA silencing systems are organized into a network with shared components and overlapping functions. MicroRNAs, and probably trans-acting small RNAs, help regulate development at the posttranscriptional level. ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584260 Sat, 01 Jan 2005 05:00:00 +0100 1584260 http://www.medworm.com/index.php?rid=1584259&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212498%26dopt%3DAbstract Authors: Waters CM, Bassler BL Bacteria communicate with one another using chemical signal molecules. As in higher organisms, the information supplied by these molecules is critical for synchronizing the activities of large groups of cells. In bacteria, chemical communication involves producing, releasing, detecting, and responding to small hormone-like molecules termed autoinducers . This process, termed quorum sensing, allows bacteria to monitor the environment for other bacteria and to alter behavior on a population-wide scale in response to changes in the number and/or species present in a community. Most quorum-sensing-controlled processes are unproductive when undertaken by an individual bacterium acting alone but become beneficial when carried out simultaneously by a large numbe... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584259 Sat, 01 Jan 2005 05:00:00 +0100 1584259 http://www.medworm.com/index.php?rid=1584258&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212499%26dopt%3DAbstract Authors: Hetzer MW, Walther TC, Mattaj IW The nuclear envelope (NE) is a highly specialized membrane that delineates the eukaryotic cell nucleus. It is composed of the inner and outer nuclear membranes, nuclear pore complexes (NPCs) and, in metazoa, the lamina. The NE not only regulates the trafficking of macromolecules between nucleoplasm and cytosol but also provides anchoring sites for chromatin and the cytoskeleton. Through these interactions, the NE helps position the nucleus within the cell and chromosomes within the nucleus, thereby regulating the expression of certain genes. The NE is not static, rather it is continuously remodeled during cell division. The most dramatic example of NE reorganization occurs during mitosis in metazoa when the NE undergoes a complete cycle of disa... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584258 Sat, 01 Jan 2005 05:00:00 +0100 1584258 http://www.medworm.com/index.php?rid=1584257&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212500%26dopt%3DAbstract Authors: Arnaout MA, Mahalingam B, Xiong JP Alphabeta heterodimeric integrins mediate dynamic adhesive cell-cell and cell-extracellular matrix (ECM) interactions in metazoa that are critical in growth and development, hemostasis, and host defense. A central feature of these receptors is their capacity to change rapidly and reversibly their adhesive functions by modulating their ligand-binding affinity. This is normally achieved through interactions of the short cytoplasmic integrin tails with intracellular proteins, which trigger restructuring of the ligand-binding site through long-range conformational changes in the ectodomain. Ligand binding in turn elicits conformational changes that are transmitted back to the cell to regulate diverse responses. The publication of the integrin alp... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584257 Sat, 01 Jan 2005 05:00:00 +0100 1584257 http://www.medworm.com/index.php?rid=1584256&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212501%26dopt%3DAbstract Authors: Doxsey S, McCollum D, Theurkauf W Centrosomes, spindle pole bodies, and related structures in other organisms are a morphologically diverse group of organelles that share a common ability to nucleate and organize microtubules and are thus referred to as microtubule organizing centers or MTOCs. Features associated with MTOCs include organization of mitotic spindles, formation of primary cilia, progression through cytokinesis, and self-duplication once per cell cycle. Centrosomes bind more than 100 regulatory proteins, whose identities suggest roles in a multitude of cellular functions. In fact, recent work has shown that MTOCs are required for several regulatory functions including cell cycle transitions, cellular responses to stress, and organization of signal transduction pat... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584256 Sat, 01 Jan 2005 05:00:00 +0100 1584256 http://www.medworm.com/index.php?rid=1584255&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212502%26dopt%3DAbstract Authors: Römisch K Secretory and transmembrane proteins enter the secretory pathway through the protein-conducting Sec61 channel in the membrane of the endoplasmic reticulum. In the endoplasmic reticulum, proteins fold, are frequently covalently modified, and oligomerize before they are packaged into transport vesicles that shuttle them to the Golgi complex. Proteins that misfold in the endoplasmic reticulum are selectively transported back across the endoplasmic reticulum membrane to the cytosol for degradation by proteasomes. Depending on the topology of the defect in the protein, cytosolic or lumenal chaperones are involved in its targeting to degradation. The export channel for misfolded proteins is likely also formed by Sec61p. Export may be powered by AAA-ATPases of the prot... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584255 Sat, 01 Jan 2005 05:00:00 +0100 1584255 http://www.medworm.com/index.php?rid=1584254&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212503%26dopt%3DAbstract Authors: Oliver G, Alitalo K The field of lymphatic research has been recently invigorated by the identification of genes and mechanisms that control various aspects of lymphatic development. We are beginning to understand how, starting from a subgroup of embryonic venous endothelial cells, the whole lymphatic system forms in a stepwise manner. The generation of genetically engineered mice with defects in different steps of the lymphangiogenic program has provided models that are increasing our understanding of the lymphatic system in health and disease. This knowledge, in turn, should lead to the development of better diagnostic methods and treatments of lymphatic disorders and tumor metastasis. PMID: 16212503 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Devel... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584254 Sat, 01 Jan 2005 05:00:00 +0100 1584254 http://www.medworm.com/index.php?rid=1584253&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212504%26dopt%3DAbstract Authors: Jiang K, Feldman LJ The establishment of the Angiosperm root apical meristem is dependent on the specification of a stem cell niche and the subsequent development of the quiescent center at the presumptive root pole. Distribution of auxin and the establishment of auxin maxima are early formative steps in niche specification that depend on the expression and distribution of auxin carriers. Auxin specifies stem cell niche formation by directly and indirectly affecting gene activities. Part of the indirect regulation by auxin may involve changes in redox, favoring local, oxidized microenvironments. Formation of a QC is required for root meristem development and elaboration. Many signals likely pass between the QC and the adjacent root meristem tissues. Disappearance of the QC is ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584253 Sat, 01 Jan 2005 05:00:00 +0100 1584253 http://www.medworm.com/index.php?rid=1584252&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212505%26dopt%3DAbstract Authors: Jutras I, Desjardins M Phagocytosis, the process by which cells engulf large particles, requires a substantial contribution of membranes. Recent studies have revealed that intracellular compartments, including endocytic organelles and the endoplasmic reticulum (ER), can engage in fusion events with the plasma membrane at the sites of nascent phagosomes. The finding that ER proteins are delivered to phagosomes, where degraded peptides are loaded onto major histocompatibility complex (MHC) class II molecules, has significantly enhanced our understanding of the immune functions associated with these organelles. Although it is well known that pathogens are killed in phagosomes, the contribution of ER proteins to phagosomes has provided a novel pathway for the loading of exogenous ... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584252 Sat, 01 Jan 2005 05:00:00 +0100 1584252 http://www.medworm.com/index.php?rid=1584251&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212506%26dopt%3DAbstract Authors: Osborne AR, Rapoport TA, van den Berg B The conserved protein-conducting channel, referred to as the Sec61 channel in eukaryotes or the SecY channel in eubacteria and archaea, translocates proteins across cellular membranes and integrates proteins containing hydrophobic transmembrane segments into lipid bilayers. Structural studies illustrate how the protein-conducting channel accomplishes these tasks. Three different mechanisms, each requiring a different set of channel binding partners, are employed to move polypeptide substrates: The ribosome feeds the polypeptide chain directly into the channel, a ratcheting mechanism is used by the eukaryotic endoplasmic reticulum chaperone BiP, and a pushing mechanism is utilized by the bacterial ATPase SecA. We review these translocatio... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584251 Sat, 01 Jan 2005 05:00:00 +0100 1584251 http://www.medworm.com/index.php?rid=1584250&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212507%26dopt%3DAbstract Authors: Lemke G, Reber M The sensory and motor components of nervous systems are connected topographically and contain neural maps of the external world. The paradigm for such maps is the precisely ordered wiring of the output cells of the eye to their synaptic targets in the tectum of the midbrain. The retinotectal map is organized in development through the graded activity of Eph receptor tyrosine kinases and their ephrin ligands. These signaling proteins are arrayed in complementary expression gradients along the orthogonal axes of the retina and tectum, and provide both input and recipient cells with Cartesian coordinates that specify their location. Molecular genetic studies in the mouse indicate that these coordinates are interpreted in the context of neuronal competition for te... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584250 Sat, 01 Jan 2005 05:00:00 +0100 1584250 http://www.medworm.com/index.php?rid=1584249&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212508%26dopt%3DAbstract Authors: Halin C, Rodrigo Mora J, Sumen C, von Andrian UH Over the past decades, intravital microscopy (IVM), the imaging of cells in living organisms, has become a valuable tool for studying the molecular determinants of lymphocyte trafficking. Recent advances in microscopy now make it possible to image cell migration and cell-cell interactions in vivo deep within intact tissues. Here, we summarize the principal techniques that are currently used in IVM, discuss options and tools for fluorescence-based visualization of lymphocytes in microvessels and tissues, and describe IVM models used to explore lymphoid and non-lymphoid organs. The latter will be introduced according to the physiologic itinerary of developing and differentiating T and B lymphocytes as they traffic through the body... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584249 Sat, 01 Jan 2005 05:00:00 +0100 1584249 http://www.medworm.com/index.php?rid=1584248&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212509%26dopt%3DAbstract Authors: Li L, Xie T Adult tissue-specific stem cells have the capacity to self-renew and generate functional differentiated cells that replenish lost cells throughout an organism's lifetime. Studies on stem cells from diverse systems have shown that stem cell function is controlled by extracellular cues from the niche and by intrinsic genetic programs within the stem cell. Here, we review the remarkable progress recently made in research regarding the stem cell niche. We compare the differences and commonalities of different stem cell niches in Drosophila ovary/testis and Caenorhabditis elegans distal tip, as well as in mammalian bone marrow, skin/hair follicle, intestine, brain, and testis. On the basis of this comparison, we summarize the common features, structure, and functions of... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584248 Sat, 01 Jan 2005 05:00:00 +0100 1584248 http://www.medworm.com/index.php?rid=1584247&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212510%26dopt%3DAbstract Authors: Marszalek JR, Lodish HF In contrast to other tissues, the nervous system is enriched in the polyunsaturated fatty acids (PUFAs): arachidonic acid (AA, 20:4 n-6) and docosahexaenoic acid (DHA, 22:6 n-3). Despite their abundance in the nervous system, AA and DHA cannot be synthesized de novo by mammals; they, or their precursors, must be ingested from dietary sources and transported to the brain. During late gestation and the early postnatal period, neurodevelopment is exceptionally rapid, and substantial amounts of PUFAs, especially DHA, are critical to ensure neurite outgrowth as well as proper brain and retina development. Here, we review the various functions of DHA in the nervous system, the proteins involved in its internalization and metabolism into phospholipids, and its... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584247 Sat, 01 Jan 2005 05:00:00 +0100 1584247 http://www.medworm.com/index.php?rid=1584246&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212511%26dopt%3DAbstract Authors: Feng XH, Derynck R The TGF-beta family comprises many structurally related differentiation factors that act through a heteromeric receptor complex at the cell surface and an intracellular signal transducing Smad complex. The receptor complex consists of two type II and two type I transmembrane serine/threonine kinases. Upon phosphorylation by the receptors, Smad complexes translocate into the nucleus, where they cooperate with sequence-specific transcription factors to regulate gene expression. The vertebrate genome encodes many ligands, fewer type II and type I receptors, and only a few Smads. In contrast to the perceived simplicity of the signal transduction mechanism with few Smads, the cellular responses to TGF-beta ligands are complex and context dependent. This raises th... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584246 Sat, 01 Jan 2005 05:00:00 +0100 1584246 http://www.medworm.com/index.php?rid=1584245&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D16212512%26dopt%3DAbstract Authors: Condeelis J, Singer RH, Segall JE The combined use of the new technologies of multiphoton-based intravital imaging, the chemotaxis-mediated collection of invasive cells, and high sensitivity expression profiling has allowed the correlation of the behavior of invasive tumor cells in vivo with their gene expression patterns. New insights have resulted including a gene expression signature for invasive cells and the tumor microenvironment invasion model. This model proposes that tumor invasion and metastasis can be studied as a problem resembling normal morphogenesis. We discuss how these new insights may lead to a better understanding of the molecular basis of the invasive behavior of tumor cells in vivo, which may result in new strategies for the diagnosis and treatment of meta... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584245 Sat, 01 Jan 2005 05:00:00 +0100 1584245 http://www.medworm.com/index.php?rid=1584279&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473857%26dopt%3DAbstract Authors: Sancho E, Batlle E, Clevers H The study of the epithelium of the adult mammalian intestine touches upon many modern aspects of biology. The epithelium is in a constant dialogue with the underlying mesenchyme to control stem cell activity, proliferation in transit-amplifying compartments, lineage commitment, terminal differentiation and, ultimately, cell death. There are spatially distinct compartments dedicated to each of these events. The Wnt, TGF-beta, BMP, Notch, and Par polarity pathways are the major players in homeostatic control of the adult epithelium. Several hereditary cancer syndromes deregulate these same signaling cascades through mutational (in)activation. Moreover, these mutations often also occur in sporadic tumors. Thus symmetry exists between the roles that t... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584279 Thu, 01 Jan 2004 05:00:00 +0100 1584279 http://www.medworm.com/index.php?rid=1584278&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473858%26dopt%3DAbstract Authors: Reddien PW, Sánchez Alvarado A The principles underlying regeneration in planarians have been explored for over 100 years through surgical manipulations and cellular observations. Planarian regeneration involves the generation of new tissue at the wound site via cell proliferation (blastema formation), and the remodeling of pre-existing tissues to restore symmetry and proportion (morphallaxis). Because blastemas do not replace all tissues following most types of injuries, both blastema formation and morphallaxis are needed for complete regeneration. Here we discuss a proliferative cell population, the neoblasts, that is central to the regenerative capacities of planarians. Neoblasts may be a totipotent stem-cell population capable of generating essentially every cell type... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584278 Thu, 01 Jan 2004 05:00:00 +0100 1584278 http://www.medworm.com/index.php?rid=1584277&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473859%26dopt%3DAbstract Authors: Schroer TA Dynactin is a multisubunit protein complex that is required for most, if not all, types of cytoplasmic dynein activity in eukaryotes. Dynactin binds dynein directly and allows the motor to traverse the microtubule lattice over long distances. A single dynactin subunit, p150Glued, is sufficient for both activities, yet dynactin contains several other subunits that are organized into an elaborate structure. It is currently believed that the bulk of the dynactin structure participates in interactions with a wide range of cellular structures, many of which are cargoes of the dynein motor. Genetic studies verify the importance of all elements of dynactin structure to its function. Although dynein can bind some membranous cargoes independently of dynactin, establishment o... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584277 Thu, 01 Jan 2004 05:00:00 +0100 1584277 http://www.medworm.com/index.php?rid=1584276&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473860%26dopt%3DAbstract Authors: Logan CY, Nusse R Tight control of cell-cell communication is essential for the generation of a normally patterned embryo. A critical mediator of key cell-cell signaling events during embryogenesis is the highly conserved Wnt family of secreted proteins. Recent biochemical and genetic analyses have greatly enriched our understanding of how Wnts signal, and the list of canonical Wnt signaling components has exploded. The data reveal that multiple extracellular, cytoplasmic, and nuclear regulators intricately modulate Wnt signaling levels. In addition, receptor-ligand specificity and feedback loops help to determine Wnt signaling outputs. Wnts are required for adult tissue maintenance, and perturbations in Wnt signaling promote both human degenerative diseases and cancer. The ne... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584276 Thu, 01 Jan 2004 05:00:00 +0100 1584276 http://www.medworm.com/index.php?rid=1584275&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473861%26dopt%3DAbstract Authors: Wei CJ, Xu X, Lo CW Gap junctions contain hydrophilic membrane channels that allow direct communication between neighboring cells through the diffusion of ions, metabolites, and small cell signaling molecules. They are made up of a hexameric array of polypeptides encoded by the connexin multi-gene family. Cell-cell communication mediated by connexins is crucial to various cellular functions, including the regulation of cell growth, differentiation, and development. Mutations in connexin genes have been linked to a variety of human diseases, including cardiovascular anomalies, peripheral neuropathy, deafness, skin disorders, and cataracts. In addition to their coupling function, recent studies suggest that connexin proteins may also mediate signaling. This could involve interac... Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584275 Thu, 01 Jan 2004 05:00:00 +0100 1584275 http://www.medworm.com/index.php?rid=1584274&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473862%26dopt%3DAbstract Authors: Mukherjee S, Maxfield FR Considerable evidence shows that lateral inhomogeneities in lipid composition and physical properties exist in biological membranes. These membrane lipid domains are proposed to play important roles in processes such as signal transduction and membrane traffic. However, there is not at present an adequate description of the nature of these lipid domains in terms of their size, abundance, composition, or dynamics. We discuss the current analyses of the properties and function of membrane domains in cells and compare their properties with chemically simpler model membrane systems that can be understood in greater detail. PMID: 15473862 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584274 Thu, 01 Jan 2004 05:00:00 +0100 1584274 http://www.medworm.com/index.php?rid=1584273&cid=s_37525_171_f&fid=37525&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D15473863%26dopt%3DAbstract Authors: Zheng Y Microtubules are dynamic polymers required for many aspects of eukaryotic cell function. The interphase microtubule network is essential for intracellular transport, organization, and cell polarization, whereas the mitotic spindle is required for chromosome segregation and cell division. Studies in different areas such as cell migration, mitosis, and asymmetric cell division have shown that Ran, Rho, and heterotrimeric G proteins regulate many aspects of microtubule functions. This review surveys how G protein-signaling coordinates microtubule polymerization and organization with specific cellular activities. PMID: 15473863 [PubMed - indexed for MEDLINE] (Source: Annual Review of Cell and Developmental Biology) Annual Review of Cell and Developmental Biology journals http://www.medworm.com/rss/comments.php?id=1584273 Thu, 01 Jan 2004 05:00:00 +0100 1584273