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 'Cell Calcium' source. Tue, 07 Feb 2012 08:48:52 +0100 http://www.medworm.com/index.php?rid=5640320&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22280812%26dopt%3DAbstract Authors: Urban N, Hill K, Wang L, Kuebler WM, Schaefer M Abstract The Ca(2+)-permeable, nonselective cation channel TRPC6 is gated via phospholipase C-activating receptors and has recently been implicated in hypoxia-induced pulmonary vasoconstriction (HPV), idiopathic pulmonary hypertension and focal segmental glomerulosclerosis (FSGS). Therefore, TRPC6 is a promising target for pharmacological interference. To identify and develop TRPC6-blocking compounds, we screened the Chembionet library, a collection of 16,671 chemically diverse drug-like compounds, for biological activity to prevent the 1-oleoyl-2-acetyl-sn-glycerol-triggered Ca(2+) influx in a stably transfected HEK(TRPC6-YFP) cell line. Hits were validated and characterised by fluorometric and electrophysiological methods. ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5640320 Tue, 24 Jan 2012 05:00:00 +0100 5640320 http://www.medworm.com/index.php?rid=5640321&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22252018%26dopt%3DAbstract Authors: Antalffy G, Mauer AS, Pászty K, Hegedus L, Padányi R, Enyedi A, Strehler EE Abstract Local Ca(2+) signaling requires proper targeting of the Ca(2+) signaling toolkit to specific cellular locales. Different isoforms of the plasma membrane Ca(2+) pump (PMCA) are responsible for Ca(2+) extrusion at the apical and basolateral membrane of polarized epithelial cells, but the mechanisms and signals for differential targeting of the PMCAs are not well understood. Recent work demonstrated that the alternatively spliced w-insert in PMCA2 directs this pump to the apical membrane. We now show that inserting the w-insert into the corresponding location of the PMCA4 isoform confers apical targeting to this normally basolateral pump. Mutation of a di-leucine motif in the C-tail thought... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5640321 Sun, 15 Jan 2012 05:00:00 +0100 5640321 http://www.medworm.com/index.php?rid=5602425&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22243899%26dopt%3DAbstract Authors: Yang SK, Steyn F, Chen C Abstract The secretion of growth hormone (GH) from somatotrophs located within the anterior pituitary gland is stimulated by endogenous hypothalamic growth hormone-releasing hormone (GHRH) and the GH secretagogue (GHS) ghrelin, and inhibited by somatotropin-releasing inhibitory factor (SRIF, also known as somatostatin). These factors bind to specific G-protein-coupled receptors on the cell membrane, and directly or indirectly modify the properties of ion channels and second messenger systems. Ultimately this results in a change in intracellular free Ca(2+) concentration ([Ca(2+)](i)) and the secretion of GH. Somatotrophs possess a variety of ion channels on their membranes, and modification of these ion channels, especially Ca(2+), K(+), and Na(+) ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5602425 Wed, 11 Jan 2012 05:00:00 +0100 5602425 http://www.medworm.com/index.php?rid=5578531&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22225940%26dopt%3DAbstract Authors: Tse A, Lee AK, Tse FW Abstract The secretion of adrenocorticotrophin (ACTH) from corticotropes is a key component in the endocrine response to stress. The resting potential of corticotropes is set by the basal activities of TWIK-related K(+) (TREK)-1 channel. Corticotrophin-releasing hormone (CRH), the major ACTH secretagogue, closes the background TREK-1 channels via the cAMP-dependent pathway, resulting in depolarization and a sustained rise in cytosolic [Ca(2+)] ([Ca(2+)](i)). By contrast, arginine vasopressin and norepinephrine evoke Ca(2+) release from the inositol trisphosphate (IP(3))-sensitive store, resulting in the activation of small conductance Ca(2+)-activated K(+) channels and hyperpolarization. Following [Ca(2+)](i) rise, cytosolic Ca(2+) is taken into the m... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5578531 Thu, 05 Jan 2012 05:00:00 +0100 5578531 http://www.medworm.com/index.php?rid=5578530&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226146%26dopt%3DAbstract Authors: Nagasawa M, Kojima I Abstract The present study was conducted to investigate localization and function of TRPV2 channel in a mouse macrophage cell line, TtT/M87. We infected an adenovirus vector encoding TRPV2 tagged with c-Myc in the extracellular domain. Immunoreactivity of c-Myc epitope exposed to the cell surface formed a ring structure, which was colocalized with markers of the podosome, namely β-integrin, paxillin and Pyk2. The ring structure was also observed in TRPV2-GFP-expressing cells using total internal reflection fluorescent microscopy. Addition of formyl-Met-Leu-Phe (fMLP) increased the number of podosome and increased the intensity of the TRPV2 signal associated with the podosome. Measurement of subplasmalenmal free calcium concentration ([Ca(2+)](pm)) rev... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5578530 Wed, 04 Jan 2012 05:00:00 +0100 5578530 http://www.medworm.com/index.php?rid=5578529&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22226147%26dopt%3DAbstract We report here a molecular and functional interaction between the TRPM2 channel and EF-hand motif-containing protein EFHC1, whose mutation causes juvenile myoclonic epilepsy (JME) via mechanisms including neuronal apoptosis. In situ hybridization analysis demonstrates TRPM2 and EFHC1 are coexpressed in hippocampal neurons and ventricle cells, while immunoprecipitation analysis demonstrates physical interaction of the N- and C-terminal cytoplasmic regions of TRPM2 with the EFHC1 protein. Coexpression of EFHC1 significantly potentiates hydrogen peroxide (H(2)O(2))- and ADPR-induced Ca(2+) responses and cationic currents via recombinant TRPM2 in HEK293 cells. Furthermore, EFHC1 enhances TRPM2-conferred susceptibility of HEK293 cells to H(2)O(2)-induced cell death, which is reversed by JME mut... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5578529 Wed, 04 Jan 2012 05:00:00 +0100 5578529 http://www.medworm.com/index.php?rid=5578533&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222090%26dopt%3DAbstract Authors: Yoo SH, Hur YS Abstract The high capacity, low affinity Ca(2+) storage protein chromogranins are marker proteins of secretory granules that contain the most Ca(2+) in secretory cells. Along with the abundantly expressed chromogranins, the IP(3)R/Ca(2+) channels, the major intracellular Ca(2+) channels, are also expressed in secretory granules the most. Chromogranins not only induce formation of secretory granules but also are suggested to produce the small IP(3)-sensitive nucleoplasmic Ca(2+) store vesicles in the nucleus. Chromogranins A (CGA) and B (CGB) also directly bind the IP(3)Rs and activate the IP(3)R/Ca(2+) channels at the intragranular pH 5.5. But at a near physiological pH 7.5 only CGB interacts with the IP(3)Rs due to stronger interaction of CGB for the IP(3)R... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5578533 Tue, 03 Jan 2012 05:00:00 +0100 5578533 http://www.medworm.com/index.php?rid=5578532&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222091%26dopt%3DAbstract Authors: Borges R, Domínguez N, Estévez-Herrera J, Pereda D, Machado JD Abstract Secretory vesicles of chromaffin cells are acidic organelles that maintain an increasing pH gradient towards the cytosol (5.5 vs. 7.3) that is mediated by V-ATPase activity. This gradient is primarily responsible for the accumulation of large concentrations of amines and Ca(2+), although the mechanisms mediating Ca(2+) uptake and release from granules, and the physiological relevance of these processes, remain unclear. The presence of a vesicular matrix appears to create a bi-compartmentalised medium in which the major fractions of solutes, including catecholamines, nucleotides and Ca(2+), are strongly associated with vesicle proteins, particularly chromogranins. This association appears to be favour... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5578532 Tue, 03 Jan 2012 05:00:00 +0100 5578532 http://www.medworm.com/index.php?rid=5560323&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209697%26dopt%3DAbstract Authors: Alvarez J Abstract Cellular Ca(2+)signaling results from a complex interplay among a variety of Ca(2+) fluxes going across the plasma membrane and across the membranes of several organelles, together with the buffering effect of large numbers of Ca(2+)-binding sites distributed along the cell architecture. Endoplasmic and sarcoplasmic reticulum, mitochondria and even nucleus have all been involved in cellular Ca(2+) signaling, and the mechanisms for Ca(2+) uptake and release from these organelles are well known. In neuroendocrine cells, the secretory granules also constitute a very important Ca(2+)-storing organelle, and the possible role of the stored Ca(2+) as a trigger for secretion has attracted considerable attention. However, this possibility is frequently overlooked... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560323 Fri, 30 Dec 2011 05:00:00 +0100 5560323 http://www.medworm.com/index.php?rid=5560322&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209698%26dopt%3DAbstract Authors: Hnatowich M, Le HD, Demoissac D, Ranson K, Yurkov V, Gilchrist JS, Omelchenko A, Hryshko LV Abstract μ-Calpain is a Ca(2+)-activated protease abundant in mammalian tissues. Here, we examined the effects of μ-calpain on three alternatively spliced variants of NCX1 using the giant, excised patch technique. Membrane patches from Xenopus oocytes expressing either heart (NCX1.1), kidney (NCX1.3), or brain (NCX1.4) variants of NCX1 were exposed to μ-calpain and their Na(+)-dependent (I(1)) and Ca(2+)-dependent (I(2)) regulatory phenotypes were assessed. For these exchangers, I(1) inactivation is evident as a Na(+)(i)-dependent decay of peak outward currents whereas I(2) regulation manifests as outward current activation by micromolar Ca(2+)(i) concentrations. Notably, with NC... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560322 Fri, 30 Dec 2011 05:00:00 +0100 5560322 http://www.medworm.com/index.php?rid=5560325&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209033%26dopt%3DAbstract Authors: García AG, Padín JF, Fernández-Morales JC, Maroto M, García-Sancho J Abstract The concept of stimulus-secretion coupling was born from experiments performed in chromaffin cells 50 years ago. Stimulation of these cells with acetylcholine enhances calcium (Ca(2+)) entry and this generates a transient elevation of the cytosolic Ca(2+) concentration ([Ca(2+)](c)) that triggers the exocytotic release of catecholamines. The control of the [Ca(2+)](c) signal is complex and depends on various classes of plasmalemmal calcium channels, cytosolic calcium buffers, the uptake and release of Ca(2+) from cytoplasmic organelles, such as the endoplasmic reticulum, mitochondria, chromaffin vesicles and the nucleus, and Ca(2+) extrusion mechanisms, such as the plasma membrane Ca(2+)-stim... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560325 Wed, 28 Dec 2011 05:00:00 +0100 5560325 http://www.medworm.com/index.php?rid=5560324&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209034%26dopt%3DAbstract We examined the possibility that, other than causing glomus cell depolarization, mitochondrial inhibition can regulate transmitter release via changes in Ca(2+) dynamics. Under whole-cell voltage clamp conditions, application of the mitochondrial inhibitors, carbonyl cyanide m-chlorophenylhydrazone (CCCP) or cyanide caused a dramatic slowing in the decay of the depolarization-triggered Ca(2+) signal in glomus cells. In contrast, inhibition of the Na(+)/Ca(2+) exchanger (NCX), plasma membrane Ca(2+)-ATPase (PMCA) pump or sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA) pump had much smaller effects. Consistent with the notion that mitochondrial Ca(2+) uptake is the dominant mechanism in cytosolic Ca(2+) removal, inhibition of the mitochondrial uniporter with ruthenium red slowed the decay ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560324 Wed, 28 Dec 2011 05:00:00 +0100 5560324 http://www.medworm.com/index.php?rid=5560326&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206647%26dopt%3DAbstract Authors: Pande J, Dimmers G, Akolkar G, Skelley L, Samson SE, Grover AK Abstract The sarco/endoplasmic reticulum (SER) Ca(2+) pool is refilled by the SER Ca(2+) pump (SERCA) using cytosolic Ca(2+) and/or extracellular Ca(2+) entering the cell. The effects of the SERCA pump inhibitor cyclopiazonic acid (CPA) were studied in pig coronary artery smooth muscle using two protocols. In protocol A, the SERCA pump was inhibited by adding CPA to cells/tissues in Ca(2+)-containing solution, whereas in protocol B, CPA was added to cells/tissues in Ca(2+)-free solution, followed by reintroduction of extracellular Ca(2+). Addition of CPA increased cytosolic Ca(2+) in cultured smooth muscle cells and elicited contraction in de-endothelialized coronary arteries in both protocols. Based on pharmac... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560326 Tue, 27 Dec 2011 05:00:00 +0100 5560326 http://www.medworm.com/index.php?rid=5560327&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22204737%26dopt%3DAbstract Authors: Jin M, Berrout J, Chen L, O'Neil RG Abstract The mouse cortical collecting duct (CCD) M-1 cells were grown to confluency on coverslips to assess the interaction between TRPV4 and Ca(2+)-activated K(+) channels. Immunocytochemistry demonstrated strong expression of TRPV4, along with the CCD marker, aquaporin-2, and the Ca(2+)-activated K(+) channels, the small conductance SK3 (K(Ca)2.3) channel and large conductance BKα channel (K(Ca)1.1). TRPV4 overexpression studies demonstrated little physical dependency of the K(+) channels on TRPV4. However, activation of TRPV4 by hypotonic swelling (or GSK1016790A, a selective agonist) or inhibition by the selective antagonist, HC-067047, demonstrated a strong dependency of SK3 and BK-α activation on TRPV4-mediated Ca(2+) influx. Se... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5560327 Mon, 26 Dec 2011 05:00:00 +0100 5560327 http://www.medworm.com/index.php?rid=5550429&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197025%26dopt%3DAbstract Authors: Yeung-Yam-Wah V, Lee AK, Tse A Abstract In rat pancreatic β cells, arachidonic acid (AA) triggered intracellular Ca(2+) release. This effect could be mimicked by eicosatetraynoic acid, indicating that AA metabolism is not required. The AA-mediated Ca(2+) signal was not affected by inhibition of ryanodine receptors or emptying of ryanodine-sensitive store but was reduced by ∼70% following the disruption of acidic stores (treatment with bafilomycin A1 or glycyl-phenylalanyl-β-naphthylamide (GPN)). The action of AA did not involve TRPM2 channels or NAADP receptors because intracellular dialysis of adenosine diphosphoribose (ADPR; an activator of TRPM2 channels) or NAADP did not affect the AA response. In contrast, stimulation of IP(3) receptors via intracellular dialysis ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5550429 Thu, 22 Dec 2011 05:00:00 +0100 5550429 http://www.medworm.com/index.php?rid=5550428&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197026%26dopt%3DAbstract Authors: Weiss E, Cytlak UM, Rees DC, Osei A, Gibson JS Abstract Phosphatidylserine (PS) is usually confined to the inner leaflet of the red blood cell (RBC) membrane. It may become externalised in various conditions, however, notably in RBCs from patients with sickle cell disease (SCD) where exposed PS may contribute to anaemic and ischaemic complications. PS externalisation requires both inhibition of the aminophospholipid translocase (or flippase) and activation of the scramblase. Both may follow from elevation of intracellular Ca(2+). Flippase inhibition occurs at low [Ca(2+)](i), about 1μM, but [Ca(2+)](i) required for scrambling is reported to be much higher (around 100μM). In this work, FITC-labelled lactadherin and FACS were used to measure externalised PS, with [Ca(2+)](... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5550428 Thu, 22 Dec 2011 05:00:00 +0100 5550428 http://www.medworm.com/index.php?rid=5550430&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22192592%26dopt%3DAbstract In conclusion, the results of this study indicate that several active conformations of CaSR, stabilized by different molecules, exist, which affect intracellular signaling distinctly. PMID: 22192592 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5550430 Tue, 20 Dec 2011 05:00:00 +0100 5550430 http://www.medworm.com/index.php?rid=5535268&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177386%26dopt%3DAbstract In this study, we designed a microarray covering a large proportion of the tobacco genome and monitored gene expression in cryptogein-elicited BY-2 cells to get a more complete view of the transcriptome changes and to assess their Ca(2+) dependence. The predominant functional gene categories affected by cryptogein included stress- and disease-related proteins, phenylpropanoid pathway, signaling components, transcription factors and cell wall reinforcement. Among the 3819 unigenes whose expression changed more than fourfold, 90% were Ca(2+) dependent, as determined by their sensitivity to lanthanum chloride. The most Ca(2+)-dependent transcripts upregulated by cryptogein were involved in defense responses or the oxylipin pathway. This genome-wide study strongly supports the importance of Ca... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535268 Thu, 15 Dec 2011 05:00:00 +0100 5535268 http://www.medworm.com/index.php?rid=5535267&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177387%26dopt%3DAbstract Authors: Constantin S, Jasoni C, Romanò N, Lee K, Herbison AE Abstract The gonadotropin-releasing hormone (GnRH) neurons are the key output cells of a complex neuronal network controlling fertility in mammals. To examine calcium homeostasis in postnatal GnRH neurons, we generated a transgenic mouse line in which the genetically encodable calcium indicator ratiometric Pericam (rPericam) was targeted to the GnRH neurons. This mouse model enabled real-time imaging of calcium concentrations in GnRH neurons in the acute brain slice preparation. Investigations in GnRH-rPericam mice revealed that GnRH neurons exhibited spontaneous, long-duration (∼8s) calcium transients. Dual electrical-calcium recordings revealed that the calcium transients were correlated perfectly with burst firing ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535267 Thu, 15 Dec 2011 05:00:00 +0100 5535267 http://www.medworm.com/index.php?rid=5535266&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177709%26dopt%3DAbstract This study contributes to the understanding of the molecular basis of early AD pathogenesis, by exploring the role of GluN2A and GluN2B subunits in the mechanism of Aβ toxicity in AD. PMID: 22177709 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535266 Wed, 14 Dec 2011 05:00:00 +0100 5535266 http://www.medworm.com/index.php?rid=5535265&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177710%26dopt%3DAbstract Authors: Rorsman P, Braun M, Zhang Q Abstract The glucoregulatory hormones insulin and glucagon are released from the β- and α-cells of the pancreatic islets. In both cell types, secretion is secondary to firing of action potentials, Ca(2+)-influx via voltage-gated Ca(2+)-channels, elevation of [Ca(2+)](i) and initiation of Ca(2+)-dependent exocytosis. Here we discuss the mechanisms that underlie the reciprocal regulation of insulin and glucagon secretion by changes in plasma glucose, the roles played by different types of voltage-gated Ca(2+)-channel present in α- and β-cells and the modulation of hormone secretion by Ca(2+)-dependent and -independent processes. We also consider how subtle changes in Ca(2+)-signalling may have profound impact on β-cell performance and increas... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535265 Wed, 14 Dec 2011 05:00:00 +0100 5535265 http://www.medworm.com/index.php?rid=5535269&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22172406%26dopt%3DAbstract Authors: Hodson DJ, Romanò N, Schaeffer M, Fontanaud P, Lafont C, Fiordelisio T, Mollard P Abstract The pulsatile secretion of hormones from the mammalian pituitary gland drives a wide range of homeostatic responses by dynamically altering the functional set-point of effector tissues. To accomplish this, endocrine cell populations residing within the intact pituitary display large-scale changes in coordinated calcium-spiking activity in response to various hypothalamic and peripheral inputs. Although the pituitary gland is structurally compartmentalized into specific and intermingled endocrine cell networks, providing a clear morphological basis for such coordinated activity, the mechanisms which facilitate the timely propagation of information between cells in situ remain largely... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535269 Tue, 13 Dec 2011 05:00:00 +0100 5535269 http://www.medworm.com/index.php?rid=5535270&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22153976%26dopt%3DAbstract Authors: Gonzales AL, Earley S Abstract The melastatin transient receptor potential (TRP) channel, TRPM4, is a critical regulator of smooth muscle membrane potential and arterial tone. Activation of the channel is Ca(2+)-dependent, but prolonged exposures to high global Ca(2+) causes rapid inactivation under conventional whole-cell patch clamp conditions. Using amphotericin B perforated whole cell patch clamp electrophysiology, which minimally disrupts cytosolic Ca(2+) dynamics, we recently showed that Ca(2+) released from 1,2,5-triphosphate receptors (IP(3)R) on the sarcoplasmic reticulum (SR) activates TRPM4 channels, producing sustained transient inward cation currents (TICCs). Thus, Ca(2+)-dependent inactivation of TRPM4 may not be inherent to the channel itself but rather is a... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535270 Wed, 07 Dec 2011 05:00:00 +0100 5535270 http://www.medworm.com/index.php?rid=5535271&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22153720%26dopt%3DAbstract Authors: Joëls M, Karst H Abstract Corticosteroid hormones, which are released in high amounts after stress, easily pass the blood-brain-barrier. In the brain they bind to intracellular receptors which act as transcriptional regulators. These receptors are highly expressed in neurons of the hippocampal formation and the amygdala, areas that play a role in (emotional) memory formation. Voltage gated Ca(2+) channels are among the most prominent targets of corticosteroid hormones. When the levels of corticosterone - the prevalent corticosteroid in rats and mice- are low, L-type Ca(2+) currents of CA1 hippocampal cells are small. However, when hormone levels rise e.g. after stress, the amplitude of L-type Ca(2+) currents will be slowly enhanced, through a process requiring DNA binding... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535271 Tue, 06 Dec 2011 05:00:00 +0100 5535271 http://www.medworm.com/index.php?rid=5535272&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22153127%26dopt%3DAbstract Authors: Bouillet LE, Cardoso AS, Perovano E, Pereira RR, Ribeiro EM, Trópia MJ, Fietto LG, Tisi R, Martegani E, Castro IM, Brandão RL Abstract Previous work from our laboratories demonstrated that the sugar-induced activation of plasma membrane H(+)-ATPase in Saccharomyces cerevisiae is dependent on calcium metabolism with the contribution of calcium influx from external medium. Our results demonstrate that a glucose-induced calcium (GIC) transporter, a new and still unidentified calcium carrier, sensitive to nifedipine and gadolinium and activated by glucose addition, seems to be partially involved in the glucose-induced activation of the plasma membrane H(+)-ATPase. On the other hand, the importance of calcium carriers that can release calcium from internal stores was analyzed... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535272 Mon, 05 Dec 2011 05:00:00 +0100 5535272 http://www.medworm.com/index.php?rid=5535273&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138111%26dopt%3DAbstract Authors: Stojilkovic SS Abstract Endocrine pituitary cells express numerous voltage-gated Na(+), Ca(2+), K(+), and Cl(-) channels and several ligand-gated channels, and they fire action potentials spontaneously. Depending on the cell type, this electrical activity can generate localized or global Ca(2+) signals, the latter reaching the threshold for stimulus-secretion coupling. These cells also express numerous G-protein-coupled receptors, which can stimulate or silence electrical activity and Ca(2+) influx through voltage-gated Ca(2+) channels and hormone release. Receptors positively coupled to the adenylyl cyclase signaling pathway stimulate electrical activity with cAMP, which activates hyperpolarization-activated cyclic nucleotide-regulated channels directly, or by cAMP-depend... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535273 Fri, 02 Dec 2011 05:00:00 +0100 5535273 http://www.medworm.com/index.php?rid=5535274&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22137240%26dopt%3DAbstract Authors: Chang JP, Habibi HR, Yu Y, Moussavi M, Grey CL, Pemberton JG Abstract Relative to mammals, the neuroendocrine control of pituitary growth hormone (GH) secretion and synthesis in teleost fish involves numerous stimulatory and inhibitory regulators, many of which are delivered to the somatotrophs via direct innervation. Among teleosts, how multifactorial regulation of somatotroph functions are mediated at the level of post-receptor signalling is best characterized in goldfish. Supplemented with recent findings, this review focuses on the known intracellular signal transduction mechanisms mediating the ligand- and function-specific actions in multifactorial control of GH release and synthesis, as well as basal GH secretion, in goldfish somatotrophs. These include membrane vol... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535274 Thu, 01 Dec 2011 05:00:00 +0100 5535274 http://www.medworm.com/index.php?rid=5535276&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133610%26dopt%3DAbstract Authors: Wong SS, Kotera I, Mills E, Suzuki H, Truong K Abstract While genetically encoded Ca(2+) indicators (GECIs) allow Ca(2+) imaging in model organisms, the gene expression is often under the control of a single promoter that may drive expression beyond, the cell types of interest. To enable more cell-type specific targeting, GECIs can be brought under the, control of the intersecting expression from two promoters. Here, we present the splitting and, reassembly of two representative GECIs (TN-XL and GCaMP2) mediated by the split intein from Nostoc, punctiforme (NpuDnaE). While the split TN-XL biosensor offered ratiometric Ca(2+) imaging, it had a, diminished Ca(2+) response relative to the native TN-XL biosensor. In contrast, the split GCaMP2, biosensor retained similar Ca(2+)... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535276 Tue, 29 Nov 2011 05:00:00 +0100 5535276 http://www.medworm.com/index.php?rid=5535275&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133611%26dopt%3DAbstract Authors: de la Fuente S, Fonteriz RI, Montero M, Alvarez J Abstract Available methods to measure mitochondrial [Ca(2+)] ([Ca(2+)](M)) include both targeted proteins and fluorescent dyes. Targeted proteins usually report much higher [Ca(2+)](M) values than fluorescent dyes, up to two orders of magnitude. However, we show here that the low-Ca(2+)-affinity dye rhod-5N provides [Ca(2+)](M) values similar to those reported by targeted aequorin, suggesting that the discrepancies are mainly due to the higher Ca(2+)-affinity of the fluorescent dyes used. We find rhod-5N has an apparent in situ intramitochondrial Kd around 0.5mM. Addition of Ca(2+) buffers containing between 4.5 and 10μM [Ca(2+)] to permeabilized cells loaded with rhod-5N induced increases in calibrated [Ca(2+)](M) up to t... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535275 Tue, 29 Nov 2011 05:00:00 +0100 5535275 http://www.medworm.com/index.php?rid=5535277&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119571%26dopt%3DAbstract Authors: Jiao Q, Takeshima H, Ishikawa Y, Minamisawa S Abstract Impaired Ca(2+) reuptake into the sarcoplasmic reticulum (SR) underlies a primary pathogenesis of heart failure in the aging heart. Sarcalumenin (SAR), a Ca(2+)-binding glycoprotein located in the longitudinal SR, regulates Ca(2+) reuptake by interacting with SR Ca(2+)-ATPase (SERCA). Here we found that the expression levels of both SAR and SERCA2 proteins were significantly downregulated in senescent wild-type mice (18-month old) and that downregulation of SAR protein preceded downregulation of SERCA2 protein. The downregulation of SERCA2 protein was greater in senescent SARKO mice than in age-matched senescent wild-type mice, which was at least in part due to progressive degradation of SERCA2 protein in SARKO mice. S... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5535277 Thu, 24 Nov 2011 05:00:00 +0100 5535277 http://www.medworm.com/index.php?rid=5421449&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22088219%26dopt%3DAbstract We report that SOCE is associated with (i) elevations of Ca(2+)-concentration in individual neuronal mitochondria ([Ca(2+)](m)). In addition, SOCE can result in (ii) hyperpolarizing neuronal membrane currents, (iii) increase in extracellular K(+)-concentration ([K(+)](o)), (iv) mitochondrial membrane depolarization, and (v) changes in intracellular redox state (NAD(P)H and FAD fluorescence), the latter reflecting responses of energy metabolism. These additional downstream effects of SOCE required concomitant muscarinic receptor activation by carbachol or acetylcholine, and were suppressed by agonist washout or application of antagonist, atropine. We conclude that muscarinic receptor activation determines the downstream effects of SOCE on neuronal membrane excitability and energy metabolism... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5421449 Mon, 14 Nov 2011 05:00:00 +0100 5421449 http://www.medworm.com/index.php?rid=5421450&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22054663%26dopt%3DAbstract Authors: Calderón-Rivera A, Andrade A, Hernández-Hernández O, González-Ramírez R, Sandoval A, Rivera M, Gomora JC, Felix R Abstract Voltage-gated calcium (Ca(V)) channels are transmembrane proteins that form Ca(2+)-selective pores gated by depolarization and are essential regulators of the intracellular Ca(2+) concentration. By providing a pathway for rapid Ca(2+) influx, Ca(V) channels couple membrane depolarization to a wide array of cellular responses including neurotransmission, muscle contraction and gene expression. Ca(V) channels fall into two major classes, low voltage-activated (LVA) and high voltage-activated (HVA). The ion-conducting pathway of HVA channels is the α(1) subunit, which typically contains associated β and α(2)δ ancillary subunits that regulate the ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5421450 Wed, 02 Nov 2011 04:00:00 +0100 5421450 http://www.medworm.com/index.php?rid=5380042&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22050845%26dopt%3DAbstract Authors: Almirza WH, Peters PH, van Zoelen EJ, Theuvenet AP Abstract Normal rat kidney (NRK) fibroblasts exhibit growth-dependent changes in electrophysiological properties and intracellular calcium dynamics. The transition from a quiescent state to a density-arrested state results in altered calcium entry characteristics. This coincides with modulation of the expression of the genes encoding the calcium channels Trpc1, Trpc6 and Orai1, and of the intracellular calcium sensor Stim1. In the present study we have used gene selective short hairpin (sh) RNAs against these various genes to investigate their role in (a) capacitative store-operated calcium entry (SOCE); (b) non-capacitative OAG-induced receptor-operated calcium entry (ROCE); and (c) prostaglandin F(2α) (PGF(2α))-induced... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5380042 Tue, 01 Nov 2011 04:00:00 +0100 5380042 http://www.medworm.com/index.php?rid=5380043&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22047666%26dopt%3DAbstract Authors: Giacomello M, De Mario A, Lopreiato R, Primerano S, Campeol M, Brini M, Carafoli E Abstract The inner ear converts sound waves into hearing signals through the mechanoelectrical transduction (MET) process. Deflection of the stereocilia bundle of hair cells causes the opening of channels that allow the entry of endolymph K(+) and Ca(2+). Ca(2+) that enters is crucial to the hearing process and is exported to the endolymph by the plasma membrane Ca(2+) pump (isoform PMCA2w/a): disturbances of the balance between Ca(2+) penetration and ejection, e.g. by pump mutations, generate deafness. Hearing loss caused by PMCA defects is frequently exacerbated by mutations in cadherin 23, a single pass stereociliar Ca(2+) binding protein that forms the tip links which permit the deflecti... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5380043 Mon, 31 Oct 2011 04:00:00 +0100 5380043 http://www.medworm.com/index.php?rid=5380044&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22036161%26dopt%3DAbstract Authors: Lamboley CR, Pape PC Abstract One aim of this article was to determine the resting concentration of free Ca(2+) in the sarcoplasmic reticulum (SR) of frog cut skeletal muscle fibers ([Ca(2+)](SR,R)) using the calcium absorbance indicator dye tetramethylmurexide (TMX). Another was to determine the ratio of [Ca(2+)](SR,R) to TMX's apparent dissociation constant for Ca(2+) (K(app)) in order to establish the capability of monitoring [Ca(2+)](SR)(t) during SR Ca(2+) release - a signal needed to determine the Ca(2+) permeability of the SR. To reveal the properties of TMX in the SR, the surface membrane was rapidly permeabilized with saponin to rapidly dissipate myoplasmic TMX. Results indicated that the concentration of Ca-free TMX in the SR was 2.8-fold greater than that in the... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5380044 Thu, 27 Oct 2011 04:00:00 +0100 5380044 http://www.medworm.com/index.php?rid=5361330&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22000496%26dopt%3DAbstract Authors: Majeed Y, Tumova S, Green BL, Seymour VA, Woods DM, Agarwal AK, Naylor J, Jiang S, Picton HM, Porter KE, O'Regan DJ, Muraki K, Fishwick CW, Beech DJ Abstract Transient Receptor Potential Melastatin 3 (TRPM3) is a widely expressed calcium-permeable non-selective cation channel that is stimulated by high concentrations of nifedipine or by physiological steroids that include pregnenolone sulphate. Here we sought to identify steroids that inhibit TRPM3. Channel activity was studied using calcium-measurement and patch-clamp techniques. Progesterone (0.01-10μM) suppressed TRPM3 activity evoked by pregnenolone sulphate. Progesterone metabolites and 17β-oestradiol were also inhibitory but the effects were relatively small. Dihydrotestosterone was an inhibitor at concentrations h... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5361330 Thu, 13 Oct 2011 04:00:00 +0100 5361330 http://www.medworm.com/index.php?rid=5297908&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978418%26dopt%3DAbstract Authors: Pancani T, Anderson KL, Porter NM, Thibault O Abstract Neuronal Ca(2+) dyshomeostasis associated with cognitive impairment and mediated by changes in several Ca(2+) sources has been seen in animal models of both aging and diabetes. In the periphery, dysregulation of intracellular Ca(2+) signals may contribute to the development of insulin resistance. In the brain, while it is well-established that type 2 diabetes mellitus is a risk factor for the development of dementia in the elderly, it is not clear whether Ca(2+) dysregulation might also affect insulin sensitivity and glucose utilization. Here we present a combination of imaging techniques testing the disappearance of the fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) a... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5297908 Tue, 04 Oct 2011 04:00:00 +0100 5297908 http://www.medworm.com/index.php?rid=5297907&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21978419%26dopt%3DAbstract Authors: Gao H, Chen X, Du X, Guan B, Liu Y, Zhang H Abstract Ion channels involved in the migration of tumor cells that is required for their invasion and metastasis. In this paper, we describe the interaction of TRPM7 channel and epidermal growth factor (EGF), an important player in cancer development in the migration of lung cancer cells. The TRPM7 currents in A549 cells were first characterized by means of electrophysiology, pharmacology and RNA interference. Removing Ca(2+) from the extracellular solution not only potentiated a large inward current, but also abolished the outward rectification. 200μM 2-APB inhibited the outward and the inward TRPM7 currents and at the same time restored the property of outward rectification. EGF greatly enhanced the migration of A549 cells, a... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5297907 Tue, 04 Oct 2011 04:00:00 +0100 5297907 http://www.medworm.com/index.php?rid=5281365&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21959089%26dopt%3DAbstract Authors: Chen S, He FF, Wang H, Fang Z, Shao N, Tian XJ, Liu JS, Zhu ZH, Wang YM, Wang S, Huang K, Zhang C Abstract Albumin, which is the most abundant component of urine proteins, exerts injurious effects on renal cells in chronic kidney diseases. However, the toxicity of albumin to podocytes is not well elucidated. Here, we show that a high concentration of albumin triggers intracellular calcium ([Ca(2+)](i)) increase through mechanisms involving the intracellular calcium store release and extracellular calcium influx in conditionally immortalized podocytes. The canonical transient receptor potential-6 (TRPC6) channel, which is associated with a subset of familial forms of focal segmental glomerulosclerosis (FSGS) and several acquired proteinuric kidney diseases, was shown to be ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5281365 Tue, 27 Sep 2011 04:00:00 +0100 5281365 http://www.medworm.com/index.php?rid=5281366&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21955751%26dopt%3DAbstract Calcium ionophore A23187 reveals calcium related cellular stress as "I-Bodies": An old actor in a new role. Cell Calcium. 2011 Sep 26; Authors: Verma A, Bhatt AN, Farooque A, Khanna S, Singh S, Dwarakanath BS Abstract Calcimycin (A23187) is an ionophore widely used in studies related to calcium dynamics in cells, but its fluorometric potential to reveal intracellular physiology has not been explored. Exploiting the microenvironment-induced changes in its fluorescence, we show that a brief exposure of cells to non-toxic concentrations (≤3μM) of the ionophore results in the characteristic organization of the ionophore forming brightly fluorescent cytoplasmic bodies termed "I-Bodies", which are closely related to stress linked disturbances/changes in calcium homeostasis. "I... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5281366 Mon, 26 Sep 2011 04:00:00 +0100 5281366 http://www.medworm.com/index.php?rid=5281367&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21944825%26dopt%3DAbstract Authors: Ramadan JW, Steiner SR, O'Neill CM, Nunemaker CS Abstract The appropriate regulation of intracellular calcium is a requirement for proper cell function and survival. This review focuses on the effects of proinflammatory cytokines on calcium regulation in the insulin-producing pancreatic beta-cell and how normal stimulus-secretion coupling, organelle function, and overall beta-cell viability are impacted. Proinflammatory cytokines are increasingly thought to contribute to beta-cell dysfunction not only in type 1 diabetes (T1D), but also in the progression of type 2 diabetes (T2D). Cytokine-induced disruptions in calcium handling result in reduced insulin release in response to glucose stimulation. Cytokines can alter intracellular calcium levels by depleting calcium from th... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5281367 Wed, 21 Sep 2011 04:00:00 +0100 5281367 http://www.medworm.com/index.php?rid=5247287&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21937109%26dopt%3DAbstract Authors: Seear RV, Lew VL Abstract Elevated [Ca(2+)](i) in human red blood cells (RBCs) activates IK1 K(+) channels leading to cell dehydration. NS309, a powerful IK1 agonist, has been shown to activate IK1 channels even at sub-physiological [Ca(2+)](i) levels. An intriguing feature of this response is its all-or-none nature, with responsive cells dehydrating fully and refractory cells retaining normal volume. We investigated the mechanism of this response suspecting cell-age involvement. We expected the younger cells, with the more vigorous plasma membrane Ca(2+) pumps (PMCA), to be the refractory cells because of their lower [Ca(2+)](i). Osmotic fragility measurements and density separation through phthalate oil were used to monitor red cell dehydration. The fraction of glycosila... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5247287 Mon, 19 Sep 2011 04:00:00 +0100 5247287 http://www.medworm.com/index.php?rid=5247290&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21930298%26dopt%3DAbstract Authors: Feldmann T, Shahar M, Baba A, Matsuda T, Lichtstein D, Rosen H Abstract Plasma membrane (PM) Na(+), K(+)-ATPase, plays crucial roles in numerous physiological processes. Cardiac steroids (CS), such as ouabain and bufalin, specifically bind to the Na(+), K(+)-ATPase and affect ionic homeostasis, signal transduction, and endocytosed membrane traffic. CS-like compounds, synthesized in and released from the adrenal gland, are considered a new family of steroid hormones. Previous studies showed that ouabain induces slow Ca(2+) oscillations in COS-7 cells by enhancing the interactions between Na(+), K(+)-ATPase, inositol 1,4,5-trisphosphate receptor (IP(3)R) and Ankyrin B (Ank-B) to form a Ca(2+) signaling micro-domain. The activation of this micro-domain, however, is independen... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5247290 Sat, 17 Sep 2011 04:00:00 +0100 5247290 http://www.medworm.com/index.php?rid=5247289&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21930299%26dopt%3DAbstract Authors: Bogeski I, Kappl R, Kummerow C, Gulaboski R, Hoth M, Niemeyer BA Abstract Reactive oxygen species (ROS) are increasingly recognized as second messengers in many cellular processes. While high concentrations of oxidants damage proteins, lipids and DNA, ultimately resulting in cell death, selective and reversible oxidation of key residues in proteins is a physiological mechanism that can transiently alter their activity and function. Defects in ROS producing enzymes cause disturbed immune response and disease. Changes in the intracellular free Ca(2+) concentration are key triggers for diverse cellular functions. Ca(2+) homeostasis thus needs to be precisely tuned by channels, pumps, transporters and cellular buffering systems. Alterations of these key regulatory proteins by ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5247289 Sat, 17 Sep 2011 04:00:00 +0100 5247289 http://www.medworm.com/index.php?rid=5247288&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21930300%26dopt%3DAbstract Authors: Ma X, Cheng KT, Wong CO, O'Neil RG, Birnbaumer L, Ambudkar IS, Yao X Abstract There is controversy as to whether TRP channels participate in mediating store-operated current (I(SOC)) and store-operated Ca(2+) entry (SOCE). Our recent study has demonstrated that TRPC1 forms heteromeric channels with TRPV4 in vascular endothelial cells and that Ca(2+) store depletion enhances the vesicle trafficking of heteromeric TRPV4-C1 channels, causing insertion of more channels into the plasma membrane in vascular endothelial cells. In the present study, we determined whether the enhanced TRPV4-C1 insertion to the plasma membrane could contribute to SOCE and I(SOC). We found that thapsigargin-induced SOCE was much lower in aortic endothelial cells derived from trpv4(-/-) or trpc1(-/-) ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5247288 Sat, 17 Sep 2011 04:00:00 +0100 5247288 http://www.medworm.com/index.php?rid=5231589&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920600%26dopt%3DAbstract Authors: Halidi N, Boittin FX, Bény JL, Meister JJ Abstract Smooth muscle contraction is regulated by changes in cytosolic Ca(2+) concentration ([Ca(2+)](i)). In response to stimulation, Ca(2+) increase in a single cell can propagate to neighbouring cells through gap junctions, as intercellular Ca(2+) waves. To investigate the mechanisms underlying Ca(2+) wave propagation between smooth muscle cells, we used primary cultured rat mesenteric smooth muscle cells (pSMCs). Cells were aligned with the microcontact printing technique and a single pSMC was locally stimulated by mechanical stimulation or by microejection of KCl. Mechanical stimulation evoked two distinct Ca(2+) waves: (1) a fast wave (2mm/s) that propagated to all neighbouring cells, and (2) a slow wave (20μm/s) that was ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5231589 Tue, 13 Sep 2011 04:00:00 +0100 5231589 http://www.medworm.com/index.php?rid=5231590&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21917311%26dopt%3DAbstract Authors: Kolikova J, Afzalov R, Surin A, Lehesjoki AE, Khiroug L Abstract Neuronal ceroid lipofuscinoses (NCLs) are a group of genetic childhood-onset progressive brain diseases characterized by a decline in mental and motor capacities, epilepsy, visual loss and premature death. Using patch clamp, fluorescence imaging and caged Ca(2+) photolysis, we evaluated the mechanisms of neuronal Ca(2+) clearance in Cln8(mnd) mice, a model of the human NCL caused by mutations in the CLN8 gene. In Cln8(mnd) hippocampal slices, Ca(2+) clearance efficiency in interneurons and, to some extent, principal neurons declined with age. In cultured Cln8(mnd) hippocampal neurons, clearance of large Ca(2+) loads was inefficient due to impaired mitochondrial Ca(2+) uptake. In contrast, neither Ca(2+) uptak... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5231590 Mon, 12 Sep 2011 04:00:00 +0100 5231590 http://www.medworm.com/index.php?rid=5219225&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21906808%26dopt%3DAbstract Authors: Collins TP, Bayliss R, Churchill GC, Galione A, Terrar DA Abstract In atrial myocytes, the sarcoplasmic reticulum (SR) has an essential role in regulating the force of contraction as a consequence of its involvement in excitation-contraction coupling (ECC). Nicotinic acid adenine dinucleotide phosphate (NAADP) is a Ca(2+) mobilizing messenger that acts to release Ca(2+) from an acidic store in mammalian cells. The photorelease of NAADP in atrial myocytes increased Ca(2+) transient amplitude with no effect on accompanying action potentials or the L-type Ca(2+) current. NAADP-AM, a cell permeant form of NAADP, increased Ca(2+) spark amplitude and frequency. The effect on Ca(2+) spark frequency could be prevented by bafilomycin A1, a vacuolar H(+)-ATPase inhibitor, or by disr... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5219225 Wed, 07 Sep 2011 04:00:00 +0100 5219225 http://www.medworm.com/index.php?rid=5219224&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21906809%26dopt%3DAbstract Authors: Oyanguren-Desez O, Rodríguez-Antigüedad A, Villoslada P, Domercq M, Alberdi E, Matute C Abstract We have previously shown that P2X7 receptor blockade prevents ATP excitotoxicity in oligodendrocytes and ameliorates chronic experimental autoimmune encephalomyelitis. Here, we have explored the putative association of functionally relevant single nucleotide polymorphisms of the P2X7 receptor gene with multiple sclerosis. We found that T allele of rs17525809 polymorphism, which yields an Ala-76 to Val change in the extracellular domain, is more frequent in multiple sclerosis patients than in controls. Importantly, P2X7 variants with Val show a gain-of-function consisting in higher calcium permeability, larger electrophysiological responses and higher ethidium uptake, and enha... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5219224 Wed, 07 Sep 2011 04:00:00 +0100 5219224 http://www.medworm.com/index.php?rid=5219223&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21906810%26dopt%3DAbstract Authors: Medic N, Desai A, Komarow H, Burch LH, Bandara G, Beaven MA, Metcalfe DD, Gilfillan AM Abstract Mast cells are considered the primary initiators of allergic diseases as a consequence of the release of multiple inflammatory mediators on activation. Although predominately activated through antigen-mediated aggregation of IgE-occupied-FcÉ›RI, they can also be induced to release mediators by other receptors and environmental stimuli. Based on studies conducted in the RBL 2H3 rodent mast cell line, the transient receptor potential melastatin 8 (TRPM8) cation channel has been implicated in the activation of mast cells in response to cold and, by inference, the development of urticaria. Here we investigated the expression and role of TRPM8 receptor, in both human and mouse non-tr... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5219223 Wed, 07 Sep 2011 04:00:00 +0100 5219223 http://www.medworm.com/index.php?rid=5141593&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839512%26dopt%3DAbstract Authors: Borysova L, Shabir S, Walsh MP, Burdyga T Abstract Ureteric peristalsis, which occurs via alternating contraction and relaxation of ureteric smooth muscle, ensures the unidirectional flow of urine from the kidney to the bladder. Understanding of the molecular mechanisms underlying ureteric excitation-contraction coupling, however, is limited. To address these knowledge deficits, and in particular to test the hypothesis that Ca(2+) sensitization via activation of the RhoA/Rho-associated kinase (ROK) pathway plays an important role in ureteric smooth muscle contraction, we carried out a thorough characterization of the electrical activity, Ca(2+) signaling, MYPT1 (myosin targeting subunit of myosin light chain phosphatase, MLCP) and myosin regulatory light chain (LC(20)) pho... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5141593 Tue, 09 Aug 2011 23:00:00 +0100 5141593 http://www.medworm.com/index.php?rid=5141592&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839513%26dopt%3DAbstract Authors: Maroto M, de Diego AM, Albiñana E, Fernandez-Morales JC, Caricati-Neto A, Jurkiewicz A, Yáñez M, Rodriguez-Franco MI, Conde S, Arce MP, Hernández-Guijo JM, García AG Abstract Compound ITH33/IQM9.21 (ITH/IQM) belongs to a new family of l-glutamic acid derivatives with antioxidant and neuroprotective properties on in vitro and in vivo models of stroke. Because neuronal damage after brain ischemia is tightly linked to excess Ca(2+) entry and neuronal Ca(2+) overload, we have investigated whether compound ITH/IQM antagonises the elevations of the cytosolic Ca(2+) concentrations ([Ca(2+)](c)) and the ensuing exocytotic responses triggered by depolarisation of bovine chromaffin cells. In fluo-4-loaded cell populations, ITH/IQM reduced the K(+)-evoked [Ca(2+)](c) transients ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5141592 Tue, 09 Aug 2011 23:00:00 +0100 5141592 http://www.medworm.com/index.php?rid=5141595&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21824653%26dopt%3DAbstract In this study, we investigated the regulation of L-type Ca(2+) channel (LTCC) in murine embryonic ventricles. The data indicated a higher phosphorylation state of LTCC at early developmental stage (EDS, E9.5-E11.5) than late developmental stage (LDS, E16.5-E18.5). An intrinsic adenylyl cyclase (AC) activity, PKA activity and basal cAMP concentration were obviously higher at EDS than LDS. The cAMP increase in the presence of isobutylmethylxanthine (IBMX, nonselective phosphodiesterase inhibitor) was further augmented at LDS but not at EDS by chelation of intracellular Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)-acetoxymethyl ester (BAPTA-AM). Furthermore, I(Ca,L) increased with time after patch rupture in LDS cardiomyocytes dialyzed with pipette solution con... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5141595 Fri, 05 Aug 2011 23:00:00 +0100 5141595 http://www.medworm.com/index.php?rid=5141596&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21820173%26dopt%3DAbstract Authors: Schwirtlich M, Kwakowsky A, Emri Z, Antal K, Lacza Z, Cselenyák A, Katarova Z, Szabó G Abstract Primary lens epithelial cell (LEC) cultures derived from newborn (P0) and one-month-old (P30) mouse lenses were used to study GABA (gamma-aminobutyric acid) signaling expression and its effect on the intracellular Ca(2+) ([Ca(2+)](i)) level. We have found that these cultures express specific cellular markers for lens epithelial and fiber cells, all components of the functional GABA signaling pathway and GABA, thus recapitulating the developmental program of the ocular lens. Activation of both GABA-A and GABA-B receptors (GABA(A)R and GABA(B)R) with the specific agonists muscimol and baclofen, respectively induces [Ca(2+)](i) transients that could be blocked by the specific ant... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5141596 Tue, 02 Aug 2011 23:00:00 +0100 5141596 http://www.medworm.com/index.php?rid=5103947&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784520%26dopt%3DAbstract Authors: Prosser BL, Hernández-Ochoa EO, Schneider MF The release of Ca(2+) ions from the sarcoplasmic reticulum through ryanodine receptor calcium release channels represents the critical step linking electrical excitation to muscular contraction in the heart and skeletal muscle (excitation-contraction coupling). Two small Ca(2+) binding proteins, S100A1 and calmodulin, have been demonstrated to bind and regulate ryanodine receptor in vitro. This review focuses on recent work that has revealed new information about the endogenous roles of S100A1 and calmodulin in regulating skeletal muscle excitation-contraction coupling. S100A1 and calmodulin bind to an overlapping domain on the ryanodine receptor type 1 to tune the Ca(2+) release process, and thereby regulate skeletal muscle functi... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5103947 Thu, 21 Jul 2011 23:00:00 +0100 5103947 http://www.medworm.com/index.php?rid=5058037&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21757230%26dopt%3DAbstract Authors: Jang M, Jang JY, Kim SH, Uhm KB, Kang YK, Kim HJ, Chung S, Park MK Dendritic Ca(2+) plays an important role not only in synaptic integration and synaptic plasticity, but also in dendritic excitability in midbrain dopamine neurons. However, the functional organization of dendritic Ca(2+) signals in the dopamine neurons remains largely unknown. We therefore investigated dendritic Ca(2+) signals by measuring glutamate-induced Ca(2+) increases along the dendrites of acutely isolated midbrain dopamine neurons. Maximal doses of glutamate induced a [Ca(2+)](c) rise with similar amplitudes in proximal and distal dendritic regions of a dopamine neuron. Glutamate receptors contributed incrementally to the [Ca(2+)](c) rise according to their distance from the soma, with a reciprocal decr... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058037 Mon, 11 Jul 2011 23:00:00 +0100 5058037 http://www.medworm.com/index.php?rid=5058038&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21752464%26dopt%3DAbstract Authors: Docampo R, Moreno SN Acidocalcisomes are acidic organelles containing calcium and a high concentration of phosphorus in the form of pyrophosphate (PP(i)) and polyphosphate (poly P). Organelles with these characteristics have been found from bacteria to human cells implying an early appearance and persistence over evolutionary time or their appearance by convergent evolution. Acidification of the organelles is driven by the presence of vacuolar proton pumps, one of which, the vacuolar proton pyrophosphatase, is absent in animals, where it is substituted by a vacuolar proton ATPase. A number of other pumps, antiporters, and channels have been described in acidocalcisomes of different species and are responsible for their internal content. Enzymes involved in the synthesis and de... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058038 Sun, 10 Jul 2011 23:00:00 +0100 5058038 http://www.medworm.com/index.php?rid=5058039&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21742378%26dopt%3DAbstract Authors: Al-Shawaf E, Tumova S, Naylor J, Majeed Y, Li J, Beech DJ The Transient Receptor Potential Canonical 5 (TRPC5) protein forms calcium-permeable cationic channels that are stimulated by G protein-coupled receptor agonists. The signaling pathways of such agonist effects are poorly understood. Here we investigated the potential for involvement of lysophosphatidylcholine (LPC) and arachidonic acid generated by group 6 (GVI) phospholipase A2 (PLA2) enzymes, focusing on stimulation of TRPC5 by sphingosine-1-phosphate (S1P) which acts via a pertussis toxin-sensitive (Gi/o protein) pathway without Ca(2+)-release. Experiments were on HEK 293 cells containing conditional expression of human TRPC5. Channel activity was recorded using an intracellular calcium indicator or whole-cell patch-... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058039 Thu, 07 Jul 2011 23:00:00 +0100 5058039 http://www.medworm.com/index.php?rid=5058040&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21741705%26dopt%3DAbstract Authors: Harper MT, Poole AW Phosphatidylserine (PS)-exposing platelets accelerate coagulation at sites of vascular injury. PS exposure requires sustained Ca(2+) signalling. Two distinct Ca(2+) entry pathways amplify and sustain platelet Ca(2+) signalling, but their relative importance in human platelets is not known. Here we examined the relative roles of store-operated Ca(2+) entry (SOCE) and non-capacitative Ca(2+) entry (NCCE) in thrombin-induced Ca(2+) signalling and PS exposure by using two Ca(2+) channel blockers. BTP-2 showed marked selectivity for SOCE over NCCE. LOE-908 specifically blocked NCCE under our conditions. Using these agents we found that SOCE is important at low thrombin concentrations whereas NCCE became increasingly important as thrombin concentration was increa... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058040 Wed, 06 Jul 2011 23:00:00 +0100 5058040 http://www.medworm.com/index.php?rid=5058042&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21741085%26dopt%3DAbstract Authors: De Smedt H, Verkhratsky A, Muallem S Ca(2+) regulates many steps in cell death mechanisms, and is potentially involved in all types of cell death. Moreover, virtually all elements of the cellular Ca(2+) toolbox seem to contribute to remodeling of the Ca(2+) signaling machinery during cell death processes. As expected from the ubiquitous nature of Ca(2+) signaling, these mechanisms are operative in all cell types, and their malfunction may lead to a wide diversity of pathological implications. The contributions in this Special Issue deal with many different aspects of the relation between Ca(2+) signaling and cell death. They illustrate the complexity of this relation, and importantly they give an outlook on potential new therapeutic targets for treatment of diseases connected ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058042 Tue, 05 Jul 2011 23:00:00 +0100 5058042 http://www.medworm.com/index.php?rid=5058041&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21741086%26dopt%3DAbstract Authors: Milla J, Montesinos MS, Machado JD, Borges R, Alonso E, Moreno-Ortega AJ, Cano-Abad MF, García AG, Ruiz-Nuño A The augmentation of neurotransmitter and hormone release produced by ouabain inhibition of plasmalemmal Na(+)/K(+)-ATPase (NKA) is well established. However, the mechanism underlying this action is still controversial. Here we have shown that in bovine adrenal chromaffin cells ouabain diminished the mobility of chromaffin vesicles, an indication of greater number of docked vesicles at subplasmalemmal exocytotic sites. On the other hand, ouabain augmented the number of vesicles undergoing exocytosis in response to a K(+) pulse, rather than the quantal size of single vesicles. Furthermore, ouabain produced a tiny and slow Ca(2+) release from the endoplasmic reticulum ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5058041 Tue, 05 Jul 2011 23:00:00 +0100 5058041 http://www.medworm.com/index.php?rid=5009153&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21724254%26dopt%3DAbstract Authors: Lloyd-Evans E, Platt FM Disrupted cellular Ca(2+) signaling is believed to play a role in a number of human diseases including lysosomal storage diseases (LSD). LSDs are a group of ∼50 diseases caused predominantly by mutations in lysosomal proteins that result in accumulation of macromolecules within the lysosome. We recently reported that Niemann-Pick type C (NPC) is the first human disease to be associated with defective lysosomal Ca(2+) uptake and defective NAADP-mediated lysosomal Ca(2+) release. These defects in NPC cells leads to the disruption in endocytosis and subsequent lipid storage that is a feature of this disease. In contrast, Chediak-Higashi Syndrome cells have been reported to have enhanced lysosomal Ca(2+) uptake whilst the TRPML1 protein defective in mucol... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=5009153 Thu, 30 Jun 2011 23:00:00 +0100 5009153 http://www.medworm.com/index.php?rid=4961713&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21684004%26dopt%3DAbstract Authors: Stout RF, Parpura V The four cephalic sensilla sheath (CEPsh) glial cells are important for development of the nervous system of Caenorhabditis elegans. Whether these invertebrate glia can generate intracellular Ca(2+) increases, a hallmark of mammalian glial cell excitability, is not known. To address this issue, we developed a transgenic worm with the specific co-expression of genetically encoded red fluorescent protein and green Ca(2+) sensor in CEPsh glial cells. This allowed us to identify CEPsh cells in culture and monitor their Ca(2+) dynamics. We show that CEPsh glial cells, in response to depolarization, generate various intracellular Ca(2+) increases mediated by voltage-gated Ca(2+) channels (VGCCs). Using a pharmacological approach, we find that the L-type is the pr... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961713 Wed, 15 Jun 2011 23:00:00 +0100 4961713 http://www.medworm.com/index.php?rid=4961714&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21665274%26dopt%3DAbstract Authors: Qu B, Al-Ansary D, Kummerow C, Hoth M, Schwarz EC Ca(2+) homeostasis controls a diversity of cellular processes including proliferation and apoptosis. A very important aspect of Ca(2+) signaling is how different Ca(2+) signals are translated into specific cell functions. In T cells, Ca(2+) signals are induced following the recognition of antigen by the T cell receptor and depend mainly on Ca(2+) influx through store-operated CRAC channels, which are mediated by ORAI proteins following their activation by STIM proteins. The complete absence of Ca(2+) influx caused by mutations in Stim1 and Orai1 leads to severe immunodeficiency. Here we summarize how Ca(2+) signals are tuned to regulate important T cell functions as proliferation, apoptosis and tolerance, the latter one being a... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961714 Thu, 09 Jun 2011 23:00:00 +0100 4961714 http://www.medworm.com/index.php?rid=4961718&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663963%26dopt%3DAbstract In conclusion, we demonstrated that [Ca(2+)](i) handling play an essential role in postconditioning action of Ucn. PMID: 21663963 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961718 Tue, 07 Jun 2011 23:00:00 +0100 4961718 http://www.medworm.com/index.php?rid=4961717&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663964%26dopt%3DAbstract Authors: Henke N, Lisak DA, Schneider L, Habicht J, Pergande M, Methner A Bax inhibitor-1 (BI-1) was initially identified for its ability to inhibit BAX-induced apoptosis in yeast cells and is the founding member of a family of highly hydrophobic proteins localized in diverse cellular membranes. It is evolutionarily conserved and orthologues from plants can substitute for mammalian BI-1 in regard to its anti-apoptotic function suggesting a high degree of functional conservation. BI-1 interacts with BCL-2 and BCL-XL and, similar to these two anti-apoptotic proteins, the effect of BI-1 on cell death involves changes in the amount of Ca(2+) releasable from intracellular stores. However, BI-1 is also a negative regulator of the endoplasmic reticulum stress sensor IRE1 α, it interacts with... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961717 Tue, 07 Jun 2011 23:00:00 +0100 4961717 http://www.medworm.com/index.php?rid=4961716&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663965%26dopt%3DAbstract Authors: Coomber SJ, Bartels EM, Elliott GF In glycerinated rabbit psoas muscle, Donnan potential measurements demonstrated that the net electric charge on the actin-myosin matrix undergoes a sharp switch-like transition at pCa(50)=6.8. The potentials are 2mV less negative at the lower pCa(2+) (P<0.001). If ATP is present, the muscle contracts and breaks the microelectrode. Therefore the rigor state was studied. There is no reason to suppose a priori that a similar voltage switch does not occur during contraction, however. Calcium dependence is still apparent in muscles stretched beyond overlap (sarcomere length>3.8μm) and is also seen in the gap filaments between the A- and I-band ends; further stretching abolishes the dependence. These experiments strongly suggest that calcium... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961716 Tue, 07 Jun 2011 23:00:00 +0100 4961716 http://www.medworm.com/index.php?rid=4961715&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21663966%26dopt%3DAbstract Authors: Supnet C, Bezprozvanny I Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide and is at present, incurable. The accumulation of toxic amyloid-beta (Aβ) peptide aggregates in AD brain is thought to trigger the extensive synaptic loss and neurodegeneration linked to cognitive decline, an idea that underlies the 'amyloid hypothesis' of AD etiology in both the familal (FAD) and sporadic forms of the disease. Genetic mutations causing FAD also result in the dysregulation of neuronal calcium (Ca(2+)) handling and may contribute to AD pathogenesis, an idea termed the 'calcium hypothesis' of AD. Mutations in presenilin proteins account for the majority of FAD cases. Presenilins function as catalytic subunits of γ-secretase involved in the generation of AÎ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4961715 Tue, 07 Jun 2011 23:00:00 +0100 4961715 http://www.medworm.com/index.php?rid=4912738&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21641034%26dopt%3DAbstract Authors: Park S, Scheffler TL, Gerrard DE Calcium is important for muscle contraction and controls many cellular processes. Although there is evidence that calcium-mediated signals regulate AMP-activated protein kinase (AMPK) activity, the molecular mechanisms by which calcium regulates AMPK are poorly understood. To compare the function of sustained vs. intermittent calcium oscillations on AMPK activity and define specific signals in this pathway, we administered mice with aminoimidazole-carboxamide-ribonucleotide (AICAR) and caffeine with or without dantrolene. AMPK activity was increased by 10d AICAR treatment (P<0.01). Ten day caffeine treatment decreased AICAR-induced AMPK activity to control level. This repressed AMPK activity was blocked by dantrolene. Different calcium frequ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4912738 Wed, 01 Jun 2011 23:00:00 +0100 4912738 http://www.medworm.com/index.php?rid=4865962&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21605904%26dopt%3DAbstract Authors: Huang WC, Chai CY, Chen WC, Hou MF, Wang YS, Chiu YC, Lu SR, Chang WC, Juo SH, Wang JY, Chang WC Histamine, an important chemical mediator, has been shown to regulate inflammation and allergic responses. Stimulation of histamine receptors results in a significant increase in cytoplasmic Ca(2+), which could be mediated by inositol trisphosphate (IP(3))-dependent store-operated Ca(2+) channels (SOC). However, the link between histamine-mediated signaling and activation of inflammatory genes such as cyclooxygenase 2 (COX-2) is still unknown. Our study indicated that the COX-2 protein was highly expressed in human lung cancer cells. Following stimulation with 10μM of histamine, both store-operated Ca(2+) entry (SOCE) and COX-2 gene expression were evoked. Histamine-mediated COX-2... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4865962 Fri, 20 May 2011 23:00:00 +0100 4865962 http://www.medworm.com/index.php?rid=4865963&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21601280%26dopt%3DAbstract Authors: Rasola A, Bernardi P A variety of stimuli utilize an increase of cytosolic free Ca(2+) concentration as a second messenger to transmit signals, through Ca(2+) release from the endoplasmic reticulum or opening of plasma membrane Ca(2+) channels. Mitochondria contribute to the tight spatiotemporal control of this process by accumulating Ca(2+), thus shaping the return of cytosolic Ca(2+) to resting levels. The rise of mitochondrial matrix free Ca(2+) concentration stimulates oxidative metabolism; yet, in the presence of a variety of sensitizing factors of pathophysiological relevance, the matrix Ca(2+) increase can also lead to opening of the permeability transition pore (PTP), a high conductance inner membrane channel. While transient openings may serve the purpose of providing... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4865963 Thu, 19 May 2011 23:00:00 +0100 4865963 http://www.medworm.com/index.php?rid=4865964&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21596434%26dopt%3DAbstract Authors: Mikoshiba K IP(3) receptor is a Ca(2+) release channel localized on the endoplasmic reticulum. IP(3) receptor is composed of three isoforms, which are expressed in various cells and tissues, and play variety of roles throughout development. I here describe the role of IP(3) receptor from oogenesis, meiotic maturation and fertilization. I also describe the Ca(2+) signaling at meiosis and mitosis, and especially the role in early embryogenesis to determine dorso-ventral axis formation. Loss of function mutation of type 1 IP(3) receptor in mouse, both by gene targeting and spontaneous mutations shows severe ataxia and other phenotypes. Interestingly, double knockouts of type 1 and type 2 exhibit cardiogenesis arrest and that of type 2 and type 3 results in exocrine secretion defi... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4865964 Mon, 16 May 2011 23:00:00 +0100 4865964 http://www.medworm.com/index.php?rid=4865965&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21571367%26dopt%3DAbstract Authors: Decuypere JP, Bultynck G, Parys JB Autophagy is a cellular process responsible for delivery of proteins or organelles to lysosomes. It participates not only in maintaining cellular homeostasis, but also in promoting survival during cellular stress situations. It is now well established that intracellular Ca(2+) is one of the regulators of autophagy. However, this control of autophagy by intracellular Ca(2+) signaling is the subject of two opposite views. On the one hand, the available evidence indicates that intracellular Ca(2+) signals, and mainly inositol 1,4,5-trisphosphate receptors (IP(3)Rs), suppress autophagy. On the other hand, elevated cytosolic Ca(2+) concentrations ([Ca(2+)](cyt)) were also shown to promote the autophagic process. Here, we will provide a critical ov... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4865965 Thu, 12 May 2011 23:00:00 +0100 4865965 http://www.medworm.com/index.php?rid=4865966&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21565403%26dopt%3DAbstract Authors: West AE Calcium-response factor (CaRF) is a unique DNA-binding protein first recognized as a transcription factor for its role in modulating transcription of the gene encoding Brain-Derived Neurotrophic Factor (BDNF) in neurons. Here I review evidence for the biological functions and transcriptional targets of CaRF in the brain and discuss potential mechanisms by which calcium-activated signaling pathways may modulate CaRF-dependent transcription. These data paint an emerging picture of CaRF as a regulatory nexus for signaling pathways that control aspects of synaptic development and neuronal function. PMID: 21565403 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4865966 Mon, 09 May 2011 23:00:00 +0100 4865966 http://www.medworm.com/index.php?rid=4813819&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21536328%26dopt%3DAbstract This study shows that in situ microglia consist of heterogeneous populations with respect to their sensitivity to neuropeptides and -transmitters. PMID: 21536328 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813819 Fri, 29 Apr 2011 23:00:00 +0100 4813819 http://www.medworm.com/index.php?rid=4813821&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21529938%26dopt%3DAbstract Authors: Wayman GA, Tokumitsu H, Davare MA, Soderling TR A change in intracellular free calcium is a common signaling mechanism that modulates a wide array of physiological processes in most cells. Responses to increased intracellular Ca(2+) are often mediated by the ubiquitous protein calmodulin (CaM) that upon binding Ca(2+) can interact with and alter the functionality of numerous proteins including a family of protein kinases referred to as CaM-kinases (CaMKs). Of particular interest are multifunctional CaMKs, such as CaMKI, CaMKII, CaMKIV and CaMKK, that can phosphorylate multiple downstream targets. This review will outline several protocols we have used to identify which members and/or isoforms of this CaMK family mediate specific cellular responses with a focus on studies in ne... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813821 Wed, 27 Apr 2011 23:00:00 +0100 4813821 http://www.medworm.com/index.php?rid=4813820&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21529939%26dopt%3DAbstract Authors: Patel S, Ramakrishnan L, Rahman T, Hamdoun A, Marchant JS, Taylor CW, Brailoiu E Accumulating evidence suggests that the endo-lysosomal system provides a substantial store of Ca(2+) that is tapped by the Ca(2+)-mobilizing messenger, NAADP. In this article, we review evidence that NAADP-mediated Ca(2+) release from this acidic Ca(2+) store proceeds through activation of the newly described two-pore channels (TPCs). We discuss recent advances in defining the sub-cellular targeting, topology and biophysics of TPCs. We also discuss physiological roles and the evolution of this ubiquitous ion channel family. PMID: 21529939 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813820 Tue, 26 Apr 2011 23:00:00 +0100 4813820 http://www.medworm.com/index.php?rid=4813822&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21524792%26dopt%3DAbstract Authors: Oláh T, Fodor J, Ruzsnavszky O, Vincze J, Berbey C, Allard B, Csernoch L When the intracellular calcium stores are depleted, a Ca(2+) influx is activated to refill these stores. This store-operated Ca(2+) entry (SOCE) depends on the cooperation of several proteins as STIM1, Orai1, and, possibly, TRPC1. To elucidate this role of TRPC1 in skeletal muscle, TRPC1 was overexpressed in C2C12 cells and SOCE was studied by measuring the changes in intracellular Ca(2+) concentration ([Ca(2+)](i)). TRPC1 overexpression significantly increased both the amplitude and the maximal rate-of-rise of SOCE. When YM-58483, an inhibitor of TRPC1 was used, these differences were eliminated, moreover, SOCE was slightly suppressed. A decrease in the expression of STIM1 together with the downregulati... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813822 Sun, 24 Apr 2011 23:00:00 +0100 4813822 http://www.medworm.com/index.php?rid=4813823&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21514957%26dopt%3DAbstract Authors: Hayato R, Higure Y, Kuba M, Nagai H, Yamashita H, Kuba K We studied how mitochondrial uncoupling by β(3)-adrenergic stimulation elicits Ca(2+) signals in rodent brown adipocytes by fluorometry of Ca(2+) concentrations ([Ca(2+)](i), [Ca(2+)](m) and [Ca(2+)](ER)) in the cytoplasm, mitochondria and the endoplasmic reticulum (ER), respectively, and mitochondrial membrane potential, using fura-2, rhod-5N, cameleon and rhodamine 123. Immunoblotting demonstrated α(1A)- and β(3)-adrenergic receptor and UCP1 in adipocytes, while RT-PCR revealed the mRNA of type 3, 7 and 9 adenylate cyclase, UCP1, UCP2, UCP3 and type 1 and 2 inositoltrisphosphate receptors. Isoproterenol and BRL37344, β-agonist, caused triphasic rises in [Ca(2+)](i) (β-responses) with mitochondrial depolarization i... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813823 Thu, 21 Apr 2011 23:00:00 +0100 4813823 http://www.medworm.com/index.php?rid=4813825&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21511333%26dopt%3DAbstract Authors: Groppi S, Belotti F, Brandão RL, Martegani E, Tisi R Glucose addition to glucose-starved Saccharomyces cerevisiae cells triggers a quick and transient influx of calcium from the extracellular environment. In yeast at least two different carrier systems were identified: a high affinity system, requiring Cch1 channel, and a low affinity system. Here we report that another calcium transport system exists in yeast, not yet identified, that can substitute the two known systems when they are inactivated. This system was called GIC (for Glucose Induced Calcium) system and it is a high affinity calcium transport system, magnesium-sensitive but nickel-resistant. Moreover, GIC transport is sensitive to gadolinium and nifedipine, but it is not sensitive to inhibition by verapamil, which... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813825 Mon, 18 Apr 2011 23:00:00 +0100 4813825 http://www.medworm.com/index.php?rid=4813824&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21511334%26dopt%3DAbstract Authors: Ariano P, Dalmazzo S, Owsianik G, Nilius B, Lovisolo D Gonadotropin-releasing hormone (GnRH)-secreting neurons are key regulators of the reproductive behaviour in vertebrates. These neurons show a peculiar migratory pattern during embryonic development, and its perturbations have profound impact on fertility and other related functional aspects. Changes in the intracellular calcium concentration, [Ca(2+)](i), induced by different extracellular signals, play a central role in the control of neuronal migration, but the available knowledge regarding GnRH neurons is still limited. Our goal was to investigate mechanisms that may be involved in the Ca(2+) dependence of the migratory behaviour in these neurons. We focused on the "classical" Transient Receptor Potential (TRPC) subfami... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813824 Mon, 18 Apr 2011 23:00:00 +0100 4813824 http://www.medworm.com/index.php?rid=4813826&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21507483%26dopt%3DAbstract Authors: Wu C, Gui GP, Fry CH Intracellular Ca(2+) control and the electrophysiological properties of guinea-pig urothelium were measured during interventions encountered during bladder filling, including cell stretch and exposure to exogenous transmitters such as ATP and muscarinic agonists. Stretch, achieved by exposure to solutions of altered osmolality, generated intracellular Ca(2+)-transients that were attenuated by Gd(3+) in isolated cells. However ATP-induced intracellular Ca(2+)-transients were unaffected by Gd(3+) but blocked by thapsigargin. ATP-dependent Ca(2+)-transients were followed by a large inward current at a holding potential of -60mV. Carbachol was without significant effect, except for a small slowing of the rate of spontaneous intracellular Ca(2+)-transients that... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813826 Sun, 17 Apr 2011 23:00:00 +0100 4813826 http://www.medworm.com/index.php?rid=4813827&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21497395%26dopt%3DAbstract Authors: Patel S, Muallem S Changes in the concentration of cytosolic Ca(2+) form the basis of a ubiquitous signal transduction pathway. Accumulating evidence implicates acidic organelles in the control of Ca(2+) dynamics in organisms across phyla. In this special issue, we discuss Ca(2+) signalling by these "acidic Ca(2+) stores" which include acidocalcisomes, vacuoles, the endo-lysosomal system, lysosome-related organelles, secretory vesicles and the Golgi complex. Ca(2+) release from these morphologically very different organelles is mediated by members of the TRP channel superfamily and two-pore channels. Inositol trisphosphate and ryanodine receptors which are traditionally viewed as endoplasmic reticulum Ca(2+) release channels can also mobilize acidic Ca(2+) stores. Ca(2+) uptak... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4813827 Wed, 13 Apr 2011 23:00:00 +0100 4813827 http://www.medworm.com/index.php?rid=4706052&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21470675%26dopt%3DAbstract Authors: Steinberg T, Ziegler N, Alonso A, Kohl A, Müssig E, Proksch S, Schulz S, Tomakidi P On the mechanistic level, response of periodontal fibroblasts permanently exposed to mechanical strain forces in vivo still lacks in clarity. Therefore, we first investigated putative strain modulation of proteins by combined 1D gel electrophoresis-based protein profiling and electrospray tandem mass spectrometry (ESI-MS). Thereafter, the exponential-modified protein abundance index (emPAI) identified strain modulation of cytoskeleton-associated molecules, including decrease in talin and microtubule-associated protein 4 (MAP4), and significant increase in myosin IC (Myo IC), the latter ones regulated by Ca(2+). These findings were corroborated by western blotting (WB) and indirect immunofluore... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4706052 Sun, 03 Apr 2011 23:00:00 +0100 4706052 http://www.medworm.com/index.php?rid=4706051&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21470676%26dopt%3DAbstract Authors: Piccari V, Deflorio C, Bigi R, Grassi F, Fucile S In slow-channel congenital myasthenic syndrome, point mutations of the endplate acetylcholine receptor (AChR) prolong channel openings, leading to excessive Ca(2+) entry with ensuing endplate degeneration and myasthenic symptoms. The Ca(2+) permeability of the human endplate AChR-channel is quite high, and is further increased by two slow-channel mutations in its É› subunit, worsening the pathological cascade. To gain further support to the hypothesis that the É› subunit plays a crucial role in controlling Ca(2+) permeability of endplate AChR-channel, in this work we measured the fractional Ca(2+) current (P(f), i.e., the percentage of the total current carried by Ca(2+) ions) of a panel of AChR carrying slow-channel mutations ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4706051 Sun, 03 Apr 2011 23:00:00 +0100 4706051 http://www.medworm.com/index.php?rid=4706053&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21466891%26dopt%3DAbstract Authors: Thomas RC To explore the effects of both external and internal pH (pH(o) and pH(i)) on the coupling between Ca(2+) extrusion and H(+) uptake by the PMCA activity in snail neurones H(+) uptake was assessed by measuring surface pH changes (ΔpH(s)) with pH-sensitive microelectrodes while Ba(2+) or Ca(2+) loads were extruded. Ru360 or ruthenium red injection showed that injected Ca(2+) was partly taken up by mitochondria, but Ca(2+) entering through channels was not. External pH was changed using a mixture of three buffers to minimise changes in buffering power. With depolarisation-induced Ca(2+) or Ba(2+) loads the ΔpH(s) were not changed significantly over the pH range 6.5-8.5. With Ca(2+) injections into cells with mitochondrial uptake blocked the ΔpH(s) were significantly s... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4706053 Sat, 02 Apr 2011 23:00:00 +0100 4706053 http://www.medworm.com/index.php?rid=4706054&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21459443%26dopt%3DAbstract Authors: Zhivotovsky B, Orrenius S Research during the past several decades has provided convincing evidence for a crucial role of the Ca(2+) ion in cell signaling. Hence, intracellular Ca(2+) transients have been implicated in most aspects of cell physiology, including gene transcription, cell cycle regulation and cell proliferation. Further, the Ca(2+) ion has been found to also play an important role in cell death regulation. Thus, necrotic cell death was early associated with intracellular Ca(2+) overload, and multiple functions in the apoptotic process have subsequently been found to be governed by Ca(2+) signaling. More recently, other modes of cell death, notably anoikis and autophagic cell death, have been demonstrated to also be modulated by Ca(2+) transients. Characteristics,... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4706054 Thu, 31 Mar 2011 23:00:00 +0100 4706054 http://www.medworm.com/index.php?rid=4651095&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21439639%26dopt%3DAbstract Authors: Barman P, Choisy SC, Hancox JC, James AF Investigations into the functional modulation of the cardiac Na(+)-Ca(2+) exchanger (NCX) by acute β-adrenoceptor/PKA stimulation have produced conflicting results. Here, we investigated (i) whether or not β-adrenoceptor activation/PKA stimulation activates current in rabbit cardiac myocytes under NCX-'selective' conditions and (ii) if so, whether a PKA-activated Cl(-)-current may contribute to the apparent modulation of NCX current (I(NCX)). Whole-cell voltage-clamp experiments were conducted at 37°C on rabbit ventricular and atrial myocytes. The β-adrenoceptor-activated currents both in NCX-'selective' and Cl(-)-selective recording conditions were found to be sensitive to 10mM Ni(2+). In contrast, the PKA-activated Cl(-) current w... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4651095 Wed, 23 Mar 2011 00:00:00 +0100 4651095 http://www.medworm.com/index.php?rid=4651096&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21435718%26dopt%3DAbstract Authors: Petersen OH, Gerasimenko OV, Tepikin AV, Gerasimenko JV Pancreatic acinar cells possess a very large Ca(2+) store in the endoplasmic reticulum, but also have extensive acidic Ca(2+) stores. Whereas the endoplasmic reticulum is principally located in the baso-lateral part of the cells, although with extensions into the granular area, the acidic stores are exclusively present in the apical part. The two types of stores can be differentiated pharmacologically because the endoplasmic reticulum accumulates Ca(2+) via SERCA pumps, whereas the acidic pools require functional vacuolar H(+) pumps in order to maintain a high intra-organellar Ca(2+) concentration. The human disease acute pancreatitis is initiated by trypsinogen activation in the apical pole and this is mostly due to eith... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4651096 Tue, 22 Mar 2011 00:00:00 +0100 4651096 http://www.medworm.com/index.php?rid=4651097&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21429578%26dopt%3DAbstract Authors: Parekh AB, Muallem S PMID: 21429578 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4651097 Mon, 21 Mar 2011 00:00:00 +0100 4651097 http://www.medworm.com/index.php?rid=4651098&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21414662%26dopt%3DAbstract Authors: Raqeeb A, Sheng J, Ao N, Braun AP In blood vessels, stimulation of the vascular endothelium by the Ca(2+)-mobilizing agonist ATP initiates a number of cellular events that cause relaxation of the adjacent smooth muscle layer. Although vascular endothelial cells are reported to express several subtypes of purinergic P2Y and P2X receptors, the major isoform(s) responsible for the ATP-induced generation of vasorelaxant signals in human endothelium has not been well characterized. To address this issue, ATP-evoked changes in cytosolic Ca(2+), membrane potential and acute nitric oxide production were measured in isolated human umbilical vein endothelial cells (HUVECs) and profiled using established P2X and P2Y receptor probes. Whereas selective P2X agonist (i.e. α,β-methyl ATP) a... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4651098 Tue, 15 Mar 2011 00:00:00 +0100 4651098 http://www.medworm.com/index.php?rid=4651099&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21402407%26dopt%3DAbstract Authors: Kawamura M, Kawamura M It is well established that astrocytes release gliotransmitters and moderate neuronal activity in the central nervous system via intracellular Ca(2+) dynamics. Astrocytic Ca(2+) oscillations are one type of spontaneous Ca(2+) mobilization that occurs in astrocytes. However, the modulation of spontaneous astrocytic Ca(2+) oscillations, especially in pathophysiological conditions, is not yet fully understood. Here, we demonstrate that activation of adenosine receptors induces a long-lasting increase in the frequency of astrocytic Ca(2+) oscillations in rat hippocampal slice cultures. The long-term facilitation of the frequency of Ca(2+) oscillations was mediated by endogenous adenosine generated via breakdown of extracellular ATP by ecto-ATPase. We also de... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4651099 Sat, 12 Mar 2011 00:00:00 +0100 4651099 http://www.medworm.com/index.php?rid=4582689&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21388679%26dopt%3DAbstract In this report we show that activation of platelets with physiological agonists was associated with 7-10 -fold rise in proteasomal activity. Elevation of cytosolic calcium with A23187 or thapsigargin resulted in significant increase in enzymatic activity, while treatment with intracellular calcium chelator or inhibitor of inositol trisphosphate receptor attenuated proteasomal enzymes in collagen-stimulated platelets. Specific inhibitors of protein kinase C as well as calpain, too, downregulated proteasome function. To conclude, proteasomal enzymatic activity in platelets is regulated by cytosolic calcium through Ca(2+)-dependent downstream effectors like calpain and protein kinase C. PMID: 21388679 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582689 Mon, 07 Mar 2011 00:00:00 +0100 4582689 http://www.medworm.com/index.php?rid=4582688&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21388680%26dopt%3DAbstract Authors: Coussee E, De Smet P, Bogaert E, Elens I, Van Damme P, Willems P, Koopman W, Van Den Bosch L, Callewaert G Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective death of motor neurons. Mutations in Cu/Zn superoxide dismutase-1 (SOD1) cause familial ALS but the molecular mechanisms whereby these mutations induce motor neuron death remain controversial. Here, we show that stable overexpression of mutant human SOD1 (G37R) - but not wild-type SOD1 (wt-SOD1) - in mouse neuroblastoma cells (N2a) results in morphological abnormalities of mitochondria accompanied by several dysfunctions. Activity of the oxidative phosphorylation complex I was significantly reduced in G37R cells and correlated with lower mitochondrial membrane potential and reduc... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582688 Mon, 07 Mar 2011 00:00:00 +0100 4582688 http://www.medworm.com/index.php?rid=4582690&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21382638%26dopt%3DAbstract Authors: Sokolow S, Luu SH, Headley AJ, Hanson AY, Kim T, Miller CA, Vinters HV, Gylys KH Synaptosomal expression of NCX1, NCX2, and NCX3, the three variants of the Na(+)-Ca(2+) exchanger (NCX), was investigated in Alzheimer's disease parietal cortex. Flow cytometry and immunoblotting techniques were used to analyze synaptosomes prepared from cryopreserved brain of cognitively normal aged controls and late stage Alzheimer's disease patients. Major findings that emerged from this study are: (1) NCX1 was the most abundant NCX isoform in nerve terminals of cognitively normal patients; (2) NCX2 and NCX3 protein levels were modulated in parietal cortex of late stage Alzheimer's disease: NCX2 positive terminals were increased in the Alzheimer's disease cohort while counts of NCX3 positive te... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582690 Sat, 05 Mar 2011 00:00:00 +0100 4582690 http://www.medworm.com/index.php?rid=4582691&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21377728%26dopt%3DAbstract Authors: Cunningham KW Fungi and animals constitute sister kingdoms in the eukaryotic domain of life. The major classes of transporters, channels, sensors, and effectors that move and respond to calcium ions were already highly networked in the common ancestor of fungi and animals. Since that time, some key components of the network have been moved, altered, relocalized, lost, or duplicated in the fungal and animal lineages and at the same time some of the regulatory circuitry has been dramatically rewired. Today the calcium transport and signaling networks in fungi provide a fresh perspective on the scene that has emerged from studies of the network in animal cells. This review provides an overview of calcium signaling networks in fungi, particularly the model yeast Saccharomyces cere... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582691 Fri, 04 Mar 2011 00:00:00 +0100 4582691 http://www.medworm.com/index.php?rid=4582692&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21376393%26dopt%3DAbstract Authors: Peiter E This review portrays the plant vacuole as both a source and a target of Ca(2+) signals. In plants, the vacuole represents a Ca(2+) store of enormous size and capacity. Total and free Ca(2+) concentrations in the vacuole vary with plant species, cell type, and environment, which is likely to have an impact on vacuolar function and the release of vacuolar Ca(2+). It is known that cytosolic Ca(2+) signals are often generated by release of the ion from internal stores, but in very few cases has a role of the vacuole been directly demonstrated. Biochemical and electrophysical studies have provided evidence for the operation of ligand- and voltage-gated Ca(2+)-permeable channels in the vacuolar membrane. The underlying molecular mechanisms are largely unknown with one excep... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582692 Wed, 02 Mar 2011 00:00:00 +0100 4582692 http://www.medworm.com/index.php?rid=4582695&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21353305%26dopt%3DAbstract Authors: Manjarrés IM, Alonso MT, García-Sancho J Cross-talk between subcellular organelles is essential for cellular Ca(2+) homeostasis. We have studied the effects of knocking down STIM1, the Ca(2+) sensor of the endoplasmic reticulum (ER), on several homeostatic Ca(2+)-handling mechanisms, including plasma membrane Ca(2+) entry and transport by ER, mitochondria and nucleus. We have used targeted aequorins to selectively measure calcium fluxes in different organelles. Actions of STIM1 were extremely selective, restricted to store operated Ca(2+) channels (SOC) and Ca(2+) uptake by the ER. No interactions with uptake or release of Ca(2+) by mitochondria or nucleus were detected. Ca(2+) exit from the ER, including passive leak, release via inositol 1,4,5-trisphosphate and ryanodine r... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582695 Tue, 01 Mar 2011 00:00:00 +0100 4582695 http://www.medworm.com/index.php?rid=4582694&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21356558%26dopt%3DAbstract Authors: Tiago T, Marques-da-Silva D, Samhan-Arias AK, Aureliano M, Gutierrez-Merino C Cytoskeleton damage is a frequent feature in neuronal cell death and one of the early events in oxidant-induced cell injury. This work addresses whether actin cytoskeleton reorganization is an early event of SIN-1-induced extracellular nitrosative/oxidative stress in cultured cerebellar granule neurons (CGN). The actin polymerization state, i.e. the relative levels of G-/F-actin, was quantitatively assessed by the ratio of the fluorescence intensities of microscopy images obtained from CGN double-labelled with Alexa594-DNase-I (for actin monomers) and Bodipy-FL-phallacidin (for actin filaments). Exposure of CGN to a flux of peroxynitrite as low as 0.5-1μM/min during 30min (achieved with 0.1mM SIN-1)... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582694 Tue, 01 Mar 2011 00:00:00 +0100 4582694 http://www.medworm.com/index.php?rid=4582693&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21367452%26dopt%3DAbstract Authors: Costa RR, Reis RI, Aguiar JF, Varanda WA LH increases the intracellular Ca(2+) concentration ([Ca(2+)](i)) in mice Leydig cells, in a process triggered by calcium influx through T-type Ca(2+) channels. Here we show that LH modulates both T-type Ca(2+) currents and [Ca(2+)](i) transients through the effects of PKA and PKC. LH increases the peak calcium current (at -20mV) by 40%. A similar effect is seen with PMA. The effect of LH is completely blocked by the PKA inhibitors H89 and a synthetic inhibitory peptide (IP-20), but only partially by chelerythrine (PKC inhibitor). LH and the blockers induced only minor changes in the voltage dependence of activation, inactivation or deactivation of the currents. Staurosporine (blocker of PKA and PKC) impaired the [Ca(2+)](i) changes ind... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4582693 Tue, 01 Mar 2011 00:00:00 +0100 4582693 http://www.medworm.com/index.php?rid=4530631&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21349579%26dopt%3DAbstract In this report we provide evidence for direct down-regulation of Ca(2+) channel current in response to low serum Na(+). In voltage-clamped rat ventricular myocytes or HEK 293 cells expressing the L-type Ca(2+) channel, a 15mM drop in extracellular Na(+) suppressed the Ca(2+) current by ∼15%; with maximal suppression of ∼30% when Na(+) levels were reduced to 100mM or less. The suppressive effects of low Na(+) on I(Ca), in part, depended on the substituting monovalent species (Li(+), Cs(+), TEA(+)), but were independent of phosphorylation state of the channel and possible influx of Ca(2+) on Na(+)/Ca(2+) exchanger. Acidification sensitized the Ca(2+) channel current to Na(+) withdrawal. Collectively our data suggest that Na(+) and H(+) may interact with regulatory site(s) at the outer re... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4530631 Tue, 22 Feb 2011 00:00:00 +0100 4530631 http://www.medworm.com/index.php?rid=4530630&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21349580%26dopt%3DAbstract This study investigated whether Aβ oligomers directly activated NMDA receptors (NMDARs) using NR1/NR2A and NR1/NR2B receptors that were heterologously expressed in Xenopus laevis oocytes. Indeed, Aβ oligomers induced inward non-desensitizing currents that were blocked in the presence of the NMDA receptor antagonists memantine, APV, and MK-801. Intriguingly, the amplitude of the responses to Aβ oligomers was greater for NR1/NR2A heteromers than for NR1/NR2B heteromers expressed in oocytes. Consistent with these findings, we observed that the increase in the cytosolic concentration of Ca(2+) induced by Aβ oligomers in cortical neurons is prevented by AP5, a broad spectrum NMDA receptor antagonist, but slightly attenuated by ifenprodil which blocks receptors with the NR2B subunit. Togethe... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4530630 Tue, 22 Feb 2011 00:00:00 +0100 4530630 http://www.medworm.com/index.php?rid=4530632&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21334066%26dopt%3DAbstract Authors: Swaminathan D, Jung P Inositol 1,4,5-trisphosphate (IP(3)) receptor is a central unit in intracellular Ca(2+) signaling. Regulation of the IP(3) receptor by calcium is well characterized. High open probability values are reported for a single IP(3) receptor in nuclear patch clamp experiments. These experimental observations are in contrast with the lower open probability values of the lipid bilayer experiments. Most theoretical models do not account for high open probabilities of the receptor. But more recently, new models of the IP(3) receptor have been put forward which are constrained by single-channel nuclear patch clamp recordings, which generate the larger open probability with the aid of an additional agonist-independent conformational transformation (AICT)-'active' sta... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4530632 Thu, 17 Feb 2011 00:00:00 +0100 4530632 http://www.medworm.com/index.php?rid=4530633&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21316101%26dopt%3DAbstract Authors: Pizzo P, Lissandron V, Capitanio P, Pozzan T The Golgi apparatus plays a central role in lipid and protein post-translational modification and sorting. Morphologically the organelle is heterogeneous and it is possible to distinguish stacks of flat cysternae (cis- and medial Golgi), tubular-reticular networks and vesicles (trans-Golgi). These morphological differences parallel a distinct functionality with a selective distribution and complementary roles of the enzymes found in the different compartments. The Golgi apparatus has been also shown to be involved in Ca(2+) signalling: it is indeed endowed with Ca(2+) pumps, Ca(2+) release channels and Ca(2+) binding proteins and is thought to participate in determining the spatio-temporal complexity of the Ca(2+) signal within the ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4530633 Thu, 10 Feb 2011 00:00:00 +0100 4530633 http://www.medworm.com/index.php?rid=4475760&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21310481%26dopt%3DAbstract Authors: Pittman JK Calcium transporters that mediate the removal of Ca(2+) from the cytosol and into internal stores provide a critical role in regulating Ca(2+) signals following stimulus induction and in preventing calcium toxicity. The vacuole is a major calcium store in many organisms, particularly plants and fungi. Two main pathways facilitate the accumulation of Ca(2+) into vacuoles, Ca(2+)-ATPases and Ca(2+)/H(+) exchangers. Here I review the biochemical and regulatory features of these transporters that have been characterised in yeast and plants. These Ca(2+) transport mechanisms are compared with those being identified from other vacuolated organisms including algae and protozoa. Studies suggest that Ca(2+) uptake into vacuoles and other related acidic Ca(2+) stores occurs b... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4475760 Tue, 08 Feb 2011 00:00:00 +0100 4475760 http://www.medworm.com/index.php?rid=4475759&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21310482%26dopt%3DAbstract Authors: Eltit JM, Szpyt J, Li H, Allen PD, Perez CF Several studies have suggested that triadin (Tdn) may be a critical component of skeletal EC-coupling. However, using Tdn-null mice we have shown that triadin ablation results in no significant disruption of skeletal EC-coupling. To analyze the role of triadin in EC-coupling signaling here we used whole-cell voltage clamp and simultaneous recording of intracellular Ca(2+) release to characterize the retrograde and orthograde signaling between RyR1 and DHPR in cultured myotubes. DHPR Ca(2+) currents elicited by depolarization of Wt and Tdn-null myotubes displayed similar current densities and voltage dependence. However, kinetic analysis of the Ca(2+) current shows that activation time constant of the slow component was slightly decre... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4475759 Tue, 08 Feb 2011 00:00:00 +0100 4475759 http://www.medworm.com/index.php?rid=4475763&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21296416%26dopt%3DAbstract In this study we determined the functional linkage, if any, between BRCA1 and CaSR. We found that mutant cells (harboring mutant BRCA1 with loss of BRCA1 expression) had a significant reduction in the expression of CaSR with a concurrent up-regulated expression of survivin and were resistant to paclitaxel by comparison to wild type cells (harboring wild type BRCA1 and expressing BRCA1). Knocking down the expression of BRCA1 in wild type cells resulted in a reduction in CaSR expression with a concurrent up-regulated expression of survivin and reduction in sensitivity to paclitaxel. Re-expression of BRCA1 in BRCA1 knocked-down wild type cells restored CaSR expression with a concurrent down-regulated expression of survivin and restoration of sensitivity to paclitaxel. Corollary, ectopic expre... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4475763 Fri, 04 Feb 2011 00:00:00 +0100 4475763 http://www.medworm.com/index.php?rid=4475766&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21295347%26dopt%3DAbstract Authors: Satin J, Schroder EA, Crump SM L-type calcium channels (LTCC) impact the function of nearly all excitable cells. The classical LTCC function is to mediate trans-sarcolemmal Ca(2+) flux. This review focuses on the contribution of a mobile segment of the LTCC that regulates ion channel function, and also serves as a regulator of transcription in the nucleus. Specifically we highlight recent work demonstrating an auto-feedback regulatory pathway whereby the LTCC transcription factor regulates the LTCC. Also discussed is acute and long-term regulation of function by the LTCC-transcription regulator. PMID: 21295347 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4475766 Wed, 02 Feb 2011 00:00:00 +0100 4475766 http://www.medworm.com/index.php?rid=4411796&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21251713%26dopt%3DAbstract Authors: Morgan AJ Sea urchin eggs have been an indispensable model system for studying egg activation and ionic signalling for at least a century. Instrumental in the discovery of two Ca(2+)-mobilizing second messengers, cyclic ADP-ribose and NAADP, the sea urchin has revolutionized cell biology for all phyla. This review attempts to summarize what we currently know about egg acidic vesicles in the context of Ca(2+) signalling. The dynamics of Ca(2+) storage, Ca(2+) mobilization, proton fluxes and two-pore channels will be discussed. PMID: 21251713 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4411796 Tue, 18 Jan 2011 00:00:00 +0100 4411796 http://www.medworm.com/index.php?rid=4411798&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21241999%26dopt%3DAbstract In this study, we have investigated the possible role of type 2 VDAC (VDAC2) in cardiac Ca(2+) signaling and Ca(2+) sparks using a lentiviral knock-down (KD) technique and two-dimensional confocal Ca(2+) imaging in immortalized autorhythmic adult atrial cells, HL-1. We confirmed high expression of VDAC2 protein in ventricular, atrial, and HL-1 cells using Western blot analysis. Infection of HL-1 cells with VDAC2-targeting lentivirus reduced the level of VDAC2 protein to ∼10%. Comparisons of autorhythmic Ca(2+) transients between wild-type (WT) and VDAC2 KD cells showed no significant change in the magnitude, decay, and beating rate of the Ca(2+) transients. Caffeine (10mM)-induced Ca(2+) release, which indicates sarcoplasmic reticulum (SR) Ca(2+) content, was not altered by VDAC2 KD. Int... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4411798 Sat, 15 Jan 2011 00:00:00 +0100 4411798 http://www.medworm.com/index.php?rid=4411797&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21242000%26dopt%3DAbstract Authors: Skelin M, Rupnik M Cyclic AMP regulates the late step of Ca(2+)-dependent exocytosis in many secretory cells through two major mechanisms: a protein kinase A-dependent and a cAMP-GEF/Epac-dependent pathway. We designed a protocol to characterize the role of these two cAMP-dependent pathways on the Ca(2+) sensitivity and kinetics of regulated exocytosis in mouse pancreatic beta cells, using a whole-cell patch-clamp based capacitance measurements. A train of depolarizing pulses or slow photo-release of caged Ca(2+) were stimuli for the exocytotic activity. In controls, due to exocytosis after slow photo-release, the C(m) change had typically two phases. We observed that the Ca(2+)-dependency of the rate of the first C(m) change follows saturation kinetics with high cooperativity... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4411797 Sat, 15 Jan 2011 00:00:00 +0100 4411797 http://www.medworm.com/index.php?rid=4411799&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21236488%26dopt%3DAbstract Authors: Baczyk D, Kingdom JC, Uhlén P The placenta sustains the developing fetus throughout gestation and its major functions include nutrition, gas and waste exchange via a variety of passive or active mechanisms. Up to 30g of calcium (Ca(2+)) actively crosses the trophoblast layer during human pregnancy. The Ca(2+) ion not only plays an important role for skeletal development but is also an essential second messenger. This review is intended to highlight the implications of Ca(2+) signaling during reproduction and specifically placentation. Initially, a Ca(2+) wave induces fertilization of the oocyte. The intracellular Ca(2+) concentration is key for the blastocyst implantation, proper placental development and function. Current knowledge of many proteins involved in placental Ca(2... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4411799 Wed, 12 Jan 2011 00:00:00 +0100 4411799 http://www.medworm.com/index.php?rid=4411800&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21232792%26dopt%3DAbstract Authors: Ukhanov K, Bobkov Y, Ache BW We show that lobster olfactory receptor neurons (ORNs), much like their vertebrate counterparts, generate a transient elevation of intracellular calcium (Ca(i)) in response to odorant activation that can be used to monitor ensemble ORN activity. This is done in antennal slice preparation in situ maintaining the polarity of the cells and the normal micro-environment of the olfactory cilia. The Ca(i) signal is ligand-specific and increases in a dose-dependent manner in response to odorant stimulation. Saturating stimulation elicits a robust increase of up to 1μM free Ca(i) within 1-2s of stimulation. The odor-induced Ca(i) response closely follows the discharge pattern of extracellular spikes elicited by odorant application, with the maximal rise in... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4411800 Tue, 11 Jan 2011 00:00:00 +0100 4411800 http://www.medworm.com/index.php?rid=4345874&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21216007%26dopt%3DAbstract Authors: Tan AR, Cai AY, Deheshi S, Rintoul GL Disruptions of mitochondrial dynamics have been implicated in the pathogenesis of neurodegenerative diseases. The regulation mechanisms of mitochondrial dynamics have not been fully elucidated; however, calcium has been suggested to play a role. In the present study, we examined the role of intracellular calcium in regulating mitochondrial morphology and motility in cortical astrocytes employing different concentrations of a calcium ionophore. High levels of calcium caused a dramatic reduction in mitochondrial length, the result of two distinct phenomena: mitochondrial remodelling (or "rounding") and fission. Quantitative analysis revealed that mitochondrial remodelling/rounding was the predominant process. In addition, mitochondrial motil... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4345874 Thu, 06 Jan 2011 00:00:00 +0100 4345874 http://www.medworm.com/index.php?rid=4345875&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21193229%26dopt%3DAbstract In this study, we investigated the molecular players involved in SOCE triggered by the SERCA pump inhibitor thapsigargin in an endothelial cell line, the EA.hy926. siRNA directed against STIM1 or Orai1 reduced Ca(2+) entry by about 50-60%, showing that a large part of the entry is independent from these proteins. Blocking the PLC or the PKC pathway completely abolished thapsigargin-induced Ca(2+) entry in cells depleted from STIM1 and/or Orai1. The phorbol ester PMA or the DAG analog OAG restored the Ca(2+) entry inhibited by PLC blockers, showing an involvement of PLC/PKC pathway in SOCE. Using pharmacological inhibitors or siRNA revealed that the PKCeta is required for Ca(2+) entry, and pharmacological inhibition of the tyrosine kinase Src also reduced Ca(2+) entry. TRPC3 silencing dimin... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4345875 Tue, 28 Dec 2010 00:00:00 +0100 4345875 http://www.medworm.com/index.php?rid=4345876&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21176957%26dopt%3DAbstract Authors: Yoo SH The majority of secretory cell calcium is stored in secretory granules that serve as the major IP(3)-dependent intracellular Ca(2+) store. Even in unicellular phytoplankton secretory granules are responsible for the IP(3)-induced Ca(2+) release that triggers exocytosis. The number of secretory granules in the cell is directly related not only to the magnitude of IP(3)-induced Ca(2+) release, which accounts for the majority of the IP(3)-induced cytoplasmic Ca(2+) release in neuroendocrine cells, but also to the IP(3) sensitivity of the cytoplasmic IP(3) receptor (IP(3)R)/Ca(2+) channels. Moreover, secretory granules contain the highest IP(3)R concentrations and the largest amounts of IP(3)Rs in any subcellular organelles in neuroendocrine cells. Secretory granules from p... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4345876 Mon, 20 Dec 2010 00:00:00 +0100 4345876 http://www.medworm.com/index.php?rid=4345878&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21176846%26dopt%3DAbstract Authors: Stiber JA, Rosenberg PB In cardiac and skeletal muscle Ca(2+) release from intracellular stores triggers actomyosin cross-bridge formation and the generation of contractile force. In the face of large fluctuations of intracellular calcium ([Ca(2+)](i)) that occur with contractile activity, myocytes are able to sense and respond to changes in workload and patterns of activation through calcium signaling pathways which modulate gene expression and cellular metabolism. Store-operated calcium influx has emerged as a mechanism by which calcium signaling pathways are activated in order to respond to the changing demands of the myocyte. Abnormalities of store-operated calcium influx may contribute to maladaptive muscle remodeling in multiple disease states. The importance of store-op... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4345878 Sun, 19 Dec 2010 00:00:00 +0100 4345878 http://www.medworm.com/index.php?rid=4345877&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21176847%26dopt%3DAbstract In conclusion our data show how SERCA function is crucial to shaping endothelial cell Ca signals and its dynamic interplay with both CCE and ER Ca releases. PMID: 21176847 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4345877 Sun, 19 Dec 2010 00:00:00 +0100 4345877 http://www.medworm.com/index.php?rid=4279190&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21168206%26dopt%3DAbstract In conclusions, AngII itself may electrically contribute to the mechanism of AF through increasing NCX expression and augmenting calcium transient, which is PKC and CREB dependent. Specific genetic knockdown of NCX attenuated calcium mediated afterdepolarization and complex electrogram. PMID: 21168206 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279190 Thu, 16 Dec 2010 00:00:00 +0100 4279190 http://www.medworm.com/index.php?rid=4279191&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21167599%26dopt%3DAbstract Authors: Rosado JA Changes in cytosolic free Ca(2+) concentration play a pivotal role in the regulation of platelet functions, from secretion of autocrine and procoagulant factors to reversible or irreversible aggregation. It has long been recognized that platelet agonists release Ca(2+) accumulated into the dense tubular system, the analogue of the endoplasmic reticulum. However, current evidence indicates that Ca(2+) can also be stored and released from a number of acidic organelles, including lysosomes and lysosome-related organelles. Ca(2+) release from the dense tubular system is mediated through phospholipase C-dependent synthesis of inositol 1,4,5-trisphosphate, whereas Ca(2+) efflux from the acidic stores seems to be associated to the second messenger nicotinic acid adenine din... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279191 Wed, 15 Dec 2010 00:00:00 +0100 4279191 http://www.medworm.com/index.php?rid=4279194&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21163523%26dopt%3DAbstract Authors: Wiegert JS, Bading H Activity-dependent gene expression is important for the formation and maturation of neuronal networks, neuronal survival and for plastic modifications within mature networks. At the level of individual neurons, expression of new protein is required for dendritic branching, synapse formation and elimination. Experience-driven synaptic activity induces membrane depolarization, which in turn evokes intracellular calcium transients that are decoded according to their source and strength by intracellular calcium sensing proteins. In order to activate the gene transcription machinery of the cell, calcium signals have to be conveyed from the site of their generation in the cytoplasm to the cell nucleus. This can occur via a variety of mechanisms and with differen... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279194 Tue, 14 Dec 2010 00:00:00 +0100 4279194 http://www.medworm.com/index.php?rid=4279193&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21163524%26dopt%3DAbstract In this study, we investigated the effects of the Na-Ca exchange (NCX) inhibitor KB-R7943, and inhibition of the sarcoplasmic reticulum calcium ATPase (SERCA), using thapsigargin or cyclopiazonic acid (CPA), on spontaneous action potentials (APs) and [Ca(2+)](i) transients from cells isolated from the rabbit AVN. Spontaneous [Ca(2+)](i) transients were monitored from undialysed AVN cells at 37°C using Fluo-4. In separate experiments, spontaneous APs and ionic currents were recorded using the whole-cell patch clamp technique. Rapid application of 5μM KB-R7943 slowed or stopped spontaneous APs and [Ca(2+)](i) transients. However, in voltage clamp experiments in addition to blocking NCX current (I(NCX)) KB-R7943 partially inhibited L-type calcium current (I(Ca,L)). Rapid reduction of extern... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279193 Tue, 14 Dec 2010 00:00:00 +0100 4279193 http://www.medworm.com/index.php?rid=4279192&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21163525%26dopt%3DAbstract Authors: Reyes RC, Perry G, Lesort M, Parpura V Immunophilins are receptors for immunosuppressive drugs such as the macrolides cyclosporin A (CsA) and FK506; correspondingly these immunophilins are referred to as cyclophilins and FK506-binding proteins (FKBPs). In particular, CsA targets cyclophilin D (CypD), which can modulate mitochondrial Ca(2+) dynamics. Since mitochondria have been implicated in the regulation of astrocytic cytosolic Ca(2+) (Ca(cyt)(2+)) dynamics and consequential Ca(2+)-dependent exocytotic release of glutamate, we investigated the role of CypD in this process. Cortical astrocytes isolated from CypD deficient mice Ppif(-/-) displayed reduced mechanically induced Ca(cyt)(2+) increases, even though these cells showed augmented exocytotic release of glutamate, when ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279192 Tue, 14 Dec 2010 00:00:00 +0100 4279192 http://www.medworm.com/index.php?rid=4279195&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21146870%26dopt%3DAbstract In this study, we tested whether TRPV6 is indeed also permeable to cations such as zinc and cadmium. We found that the basal intracellular calcium concentration was higher in HEK293 cells transfected with hTRPV6 than in non-transfected cells, and that this difference almost disappeared in nominally calcium-free solution. Live cell imaging experiments with Fura-2 and NewPort Green DCF showed that overexpression of human TRPV6 increased the permeability for Ca(2+), Ba(2+), Sr(2+), Mn(2+), Zn(2+), Cd(2+), and interestingly also for La(3+) and Gd(3+). These results were confirmed using the patch clamp technique. (45)Ca uptake experiments showed that cadmium, lanthanum and gadolinium were also highly efficient inhibitors of TRPV6-mediated calcium influx at higher micromolar concentrations. Our ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279195 Fri, 10 Dec 2010 00:00:00 +0100 4279195 http://www.medworm.com/index.php?rid=4279197&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21146212%26dopt%3DAbstract Authors: Alonso MT, García-Sancho J Ca(2+) signalling is important for controlling gene transcription. Changes of the cytosolic Ca(2+) ([Ca(2+)](C)) may promote migration of transcription factors or transcriptional regulators to the nucleus. Changes of the nucleoplasmic Ca(2+) ([Ca(2+)](N)) can also regulate directly gene expression. [Ca(2+)](N) may change by propagation of [Ca(2+)](C) changes through the nuclear envelope or by direct release of Ca(2+) inside the nucleus. In the last case nuclear and cytosolic signalling can be dissociated. Phosphatidylinositol bisphosphate, phospholipase C and cyclic ADP-ribosyl cyclase are present inside the nucleus. Inositol trisphosphate receptors (IP(3)R) and ryanodine receptors (RyR) have also been found in the nucleus and can be activated by ag... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279197 Thu, 09 Dec 2010 00:00:00 +0100 4279197 http://www.medworm.com/index.php?rid=4279196&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21146213%26dopt%3DAbstract We examined the mechanisms involved in the [Ca(2+)](i) response to the extracellular hypotonicity in the principal cells of freshly isolated rat cortical collecting duct (CCD), using Fura-2/AM fluorescence imaging. Reduction of extracellular osmolality from 305 (control) to 195mosmol/kgH(2)O (hypotonic) evoked transient increase in [Ca(2+)](i) of principal cells of rat CCDs. The [Ca(2+)](i) increase was markedly attenuated by the removal of extracellular Ca(2+)(.) The application of a P(2) purinoceptor antagonist, suramin failed to inhibit the hypotonicity-induced [Ca(2+)](i) increase. The [Ca(2+)](i) increase in response to extracellular hypotonicity was not influenced by application of Gd(3+) and ruthenium red. On the other hand, a voltage-gated Ca(2+) channel inhibitor, nicardipine, sig... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4279196 Thu, 09 Dec 2010 00:00:00 +0100 4279196 http://www.medworm.com/index.php?rid=4202756&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21106236%26dopt%3DAbstract Authors: Greensmith DJ, Eisner DA, Nirmalan M Elevations in reactive oxygen species are implicated in many disease states and cause systolic and diastolic myocardial dysfunction. To understand the underlying cellular dysfunction, we characterised the effects of H(2)O(2) on [Ca(2+)](i) handling and contractility in the rat ventricular myocyte. This was achieved using patch clamping, [Ca(2+)](i) measurement using Fluo-3, video edge detection and confocal microscopy. All experiments were performed at 37°C. 200μM H(2)O(2) resulted in a 44% decrease in the [Ca(2+)](i) transient amplitude, a 30% increase in diastolic [Ca(2+)](i) and an 18% decrease in the rate of systolic Ca(2+) removal. This was associated with a 61% reduction in systolic shortening, a contracture of 3μm and a 42% increa... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4202756 Mon, 22 Nov 2010 00:00:00 +0100 4202756 http://www.medworm.com/index.php?rid=4202755&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21106237%26dopt%3DAbstract Authors: Eisner V, Parra V, Lavandero S, Hidalgo C, Jaimovich E Mitochondria sense cytoplasmic Ca(2+) signals in many cell types. In mammalian skeletal myotubes, depolarizing stimuli induce two independent cytoplasmic Ca(2+) signals: a fast signal associated with contraction and a slow signal that propagates to the nucleus and regulates gene expression. How mitochondria sense and possibly affect these cytoplasmic Ca(2+) signals has not been reported. We investigated here (a) the emergence of mitochondrial Ca(2+) signals in response to electrical stimulation of myotubes, (b) the contribution of mitochondrial Ca(2+) transients to ATP generation and (c) the influence of mitochondria as modulators of cytoplasmic and nuclear Ca(2+) signals. Rhod2 and Fluo3 fluorescence determinations reveal... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4202755 Mon, 22 Nov 2010 00:00:00 +0100 4202755 http://www.medworm.com/index.php?rid=4202754&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21106238%26dopt%3DAbstract Authors: Wang F, Zhang Y, Jiang X, Zhang Y, Zhang L, Gong S, Liu C, Zhou L, Tao J Neuromedin U (NMU) has recently been reported to play a role in nociception. However, to date, the relevant mechanisms still remain unknown. In the present study, we investigated the expression profile of NMU receptors in mouse dorsal root ganglia (DRG) and identified a novel functional role of NMU in modulating T-type Ca(2+) channel currents (T-currents) as well as membrane excitability in small DRG neurons. We found that NMU inhibited T-currents in a dose-dependent manner in mouse small DRG neurons that endogenously expressed NMU type 1 (NMUR1), but not NMUR2 receptors. NMU (1μM) reversibly inhibited T-currents by ∼27.4%. This inhibitory effect was blocked by GDP-β-S or pertussis toxin (PTX), indica... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4202754 Mon, 22 Nov 2010 00:00:00 +0100 4202754 http://www.medworm.com/index.php?rid=4202757&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21094527%26dopt%3DAbstract Authors: Harper MT, Molkentin JD, Poole AW A rise in intracellular calcium concentration ([Ca(2+)](i)) is necessary for platelet activation. A major component of the [Ca(2+)](i) elevation occurs through store-operated Ca(2+) entry (SOCE). The aim of this study was to understand the contribution of the classical PKC isoform, PKCα to platelet SOCE, using platelets from PKCα-deficient mice. SOCE was reduced by approximately 50% in PKCα(-/-) platelets, or following treatment with bisindolylmaleimide I, a PKC inhibitor. However, TG-induced Mn(2+) entry was unaffected, which suggests that divalent cation entry through store-operated channels is not directly regulated. Blocking the autocrine action of secreted ADP or 5-HT on its receptors did not reproduce the effect of PKCα deficiency. I... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4202757 Fri, 19 Nov 2010 00:00:00 +0100 4202757 http://www.medworm.com/index.php?rid=4202758&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21093050%26dopt%3DAbstract Authors: Szewczyk MM, Pande J, Akolkar G, Grover AK The purpose of this study was to invent an extracellular inhibitor selective for the plasma membrane Ca(2+) pump(s) (PMCA) isoform 1. PMCA extrude Ca(2+) from cells during signalling and homeostasis. PMCA isoforms are encoded by 4 genes (PMCA1-4). Pig coronary artery endothelium and smooth muscle express the genes PMCA1 and 4. We showed that the endothelial cells contained mostly PMCA1 protein while smooth muscle cells had mostly PMCA4. A random peptide phage display library was screened for binding to synthetic extracellular domain 1 of PMCA1. The selected phage population was screened further by affinity chromatography using PMCA from rabbit duodenal mucosa which expressed mostly PMCA1. The peptide displayed by the selected phage wa... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4202758 Wed, 17 Nov 2010 00:00:00 +0100 4202758 http://www.medworm.com/index.php?rid=4187177&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21084119%26dopt%3DAbstract Authors: Go W, Bessarab D, Korzh V The molecular mechanisms of development of mechanosensory hair cells have been tackled successfully due to in vivo studies in the zebrafish lateral line. The enhancer trap (ET) transgenic line, SqET4 was instrumental in these studies even despite a lack of a link of its GFP expression pattern to a particular gene(s). We mapped the Tol2 transposon insertion of the SqET4 transgenics onto Chr. 4 next to a gene encoding Atp2b1a (Pmca1) - one of the four PMCAs acting to export Ca(2+) from a cell. atp2b1a expression recapitulates that of GFP during the development of mechanoreceptors of the inner ear and lateral line. atp2b1a expression correlates with the regeneration of these cells. Thus, SqET4 represents the Tg:atp2b1a-GFP line, which links Ca(2+) metabo... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4187177 Mon, 15 Nov 2010 00:00:00 +0100 4187177 http://www.medworm.com/index.php?rid=4187176&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21084120%26dopt%3DAbstract Authors: Machaca K Changes in the concentration and spatial distribution of Ca(2+) ions in the cytoplasm constitute a ubiquitous intracellular signaling module in cellular physiology. With the advent of Ca(2+) dyes that allow direct visualization of Ca(2+) transients, combined with powerful experimental tools such as electrophysiological recordings, intracellular Ca(2+) transients have been implicated in practically every aspect of cellular physiology, including cellular proliferation. Ca(2+) signals are associated with different phases of the cell cycle and interfering with Ca(2+) signaling or downstream pathways often disrupts progression of the cell cycle. Although there exists a dependence between Ca(2+) signals and the cell cycle the mechanisms involved are not well defined and gi... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4187176 Mon, 15 Nov 2010 00:00:00 +0100 4187176 http://www.medworm.com/index.php?rid=4187178&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21075448%26dopt%3DAbstract Authors: Shibao K, Fiedler MJ, Nagata J, Minagawa N, Hirata K, Nakayama Y, Iwakiri Y, Nathanson MH, Yamaguchi K The inositol 1,4,5-trisphosphate receptor (InsP3R) mediates Ca(2+) signaling in epithelia and regulates cellular functions such as secretion, apoptosis and cell proliferation. Loss of one or more InsP3R isoform has been implicated in disease processes such as cholestasis. Here we examined whether gain of expression of InsP3R isoforms also may be associated with development of disease. Expression of all three InsP3R isoforms was evaluated in tissue from colorectal carcinomas surgically resected from 116 patients. Type I and II InsP3Rs were seen in both normal colorectal mucosa and colorectal cancer, while type III InsP3R was observed only in colorectal cancer. Type III InsP3R ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4187178 Fri, 12 Nov 2010 00:00:00 +0100 4187178 http://www.medworm.com/index.php?rid=4187179&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21074851%26dopt%3DAbstract Authors: Ritchie MF, Zhou Y, Soboloff J Ca(2+) is a dynamic cellular secondary messenger which mediates a vast array of cellular responses. Control over these processes is achieved via an extensive combination of pumps and channels which regulate the concentration of Ca(2+) within not only the cytosol but also all intracellular compartments. Precisely how these pumps and channels are regulated is only partially understood, however, recent investigations have identified members of the Early Growth Response (EGR) family of zinc finger transcription factors as critical players in this process. The roles of several other transcription factors in control of Ca(2+) homeostasis have also been demonstrated, including Wilms Tumor Suppressor 1 (WT1), Nuclear Factor of Activated T cells (NFAT) an... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4187179 Thu, 11 Nov 2010 00:00:00 +0100 4187179 http://www.medworm.com/index.php?rid=4139968&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21047682%26dopt%3DAbstract Authors: Waldeck-Weiermair M, Duan X, Naghdi S, Khan MJ, Trenker M, Malli R, Graier WF Uncoupling proteins 2 and 3 (UCP2/3) are essential for mitochondrial Ca(2+) uptake but both proteins exhibit distinct activities in regard to the source and mode of Ca(2+) mobilization. In the present work, structural determinants of their contribution to mitochondrial Ca(2+) uptake were explored. Previous findings indicate the importance of the intermembrane loop 2 (IML2) for the contribution of UCP2/3. Thus, the IML2 of UCP2/3 was substituted by that of UCP1. These chimeras had no activity in mitochondrial uptake of intracellularly released Ca(2+), while they mimicked the wild-type proteins by potentiating mitochondrial sequestration of entering Ca(2+). Alignment of the IML2 sequences revealed that... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4139968 Mon, 01 Nov 2010 00:00:00 +0100 4139968 http://www.medworm.com/index.php?rid=4139967&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21047683%26dopt%3DAbstract Authors: Komori Y, Tanaka M, Kuba M, Ishii M, Abe M, Kitamura N, Verkhratsky A, Shibuya I, Dayanithi G Multiple mechanisms that maintain Ca(2+) homeostasis and provide for Ca(2+) signalling operate in the somatas and neurohypophysial nerve terminals of supraoptic nucleus (SON) neurones. Here, we examined the Ca(2+) clearance mechanisms of SON neurones from adult rats by monitoring the effects of the selective inhibition of different Ca(2+) homeostatic molecules on cytosolic Ca(2+) ([Ca(2+)](i)) transients in isolated SON neurones. In addition, we measured somatodendritic vasopressin (AVP) release from intact SON tissue in an attempt to correlate it with [Ca(2+)](i) dynamics. When bathing the cells in a Na(+)-free extracellular solution, thapsigargin, cyclopiazonic acid (CPA), carbonyl ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4139967 Mon, 01 Nov 2010 00:00:00 +0100 4139967 http://www.medworm.com/index.php?rid=4139970&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21035851%26dopt%3DAbstract In conclusion, the TRPV5 channel is susceptible for helix breaking mutations and the proximal intracellular region of TM5 of this channel plays an important role in Ca(2+)-dependent inactivation. PMID: 21035851 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4139970 Thu, 28 Oct 2010 00:00:00 +0100 4139970 http://www.medworm.com/index.php?rid=4139969&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21035852%26dopt%3DAbstract In conclusion, this work demonstrates that SACs in rat PASMCs can be activated by membrane stretch as well as hypotonic stimulation and are responsible for [Ca(2+)](i) increase. The link between SACs activation-induced calcium response and myogenic tone in chronically hypoxic rats suggests that SACs are an important element for the increased pulmonary vascular tone in PAH and that they may represent a molecular target for PAH treatment. PMID: 21035852 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4139969 Thu, 28 Oct 2010 00:00:00 +0100 4139969 http://www.medworm.com/index.php?rid=4125353&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20980052%26dopt%3DAbstract Authors: Kajiya H, Okamoto F, Nemoto T, Kimachi K, Toh-Goto K, Nakayana S, Okabe K The receptor activator of NFκB ligand (RANKL) induces Ca(2+) oscillations and activates the Nuclear Factor of Activated T cells 1 (NFATc1) during osteoclast differentiation (osteoclastogenesis). Ca(2+) oscillations are an important trigger signal for osteoclastogenesis, however the molecular basis of Ca(2+) permeable influx pathways serving Ca(2+) oscillations has not yet been identified. Using a DNA microarray, we found that Transient Receptor Potential Vanilloid channels 2 (TRPV2) are expressed significantly in RANKL-treated RAW264.7 cells (preosteoclasts) compared to untreated cells. Therefore, we further investigated the expression and functional role of TRPV2 on Ca(2+) oscillations and osteoclastog... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4125353 Mon, 25 Oct 2010 00:00:00 +0100 4125353 http://www.medworm.com/index.php?rid=4088909&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20965565%26dopt%3DAbstract Authors: Liu XH, Zhang ZY, Andersson KB, Husberg C, Enger UH, Ræder MG, Christensen G, Louch WE Reduced sarco(endo)plasmic reticulum (SR) Ca(2+) ATPase (SERCA2) contributes to the impaired cardiomyocyte Ca(2+) homeostasis observed in heart failure. We hypothesized that a reduction in SERCA2 also elicits myocardial ER/SR stress responses, including unfolded protein responses (UPR) and cardiomyocyte apoptosis, which may additionally contribute to the pathophysiology of this condition. Left ventricular myocardium from mice with cardiomyocyte-specific tamoxifen-inducible disruption of Serca2 (SERCA2 KO) was compared with aged-matched controls. In SERCA2 KO hearts, SERCA2 protein levels were markedly reduced to 2% of control values at 7 weeks following tamoxifen treatment. Serca2 disruptio... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4088909 Mon, 18 Oct 2010 23:00:00 +0100 4088909 http://www.medworm.com/index.php?rid=4088910&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20952058%26dopt%3DAbstract Authors: Wong LC, Lu B, Tan KW, Fivaz M Advances in fluorescence live cell imaging over the last decade have revolutionized cell biology by providing access to single-cell information in space and time. One current limitation of live-cell imaging is the lack of automated procedures to analyze single-cell data in large cell populations. Most commercially available image processing softwares do not have built-in image segmentation tools that can automatically and accurately extract single-cell data in a time series. Consequently, individual cells are usually identified manually, a process which is time consuming and inherently low-throughput. We have developed a MATLAB-based image segmentation algorithm that reliably detects individual cells in dense populations and measures their fluore... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4088910 Thu, 14 Oct 2010 23:00:00 +0100 4088910 http://www.medworm.com/index.php?rid=4065663&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20934218%26dopt%3DAbstract Authors: Cho Y, Jang Y, Yang YD, Lee CH, Lee Y, Oh U Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, transient receptor potential subtype M8 (TRPM8) is activated by cold and menthol, we hypothesized that this channel mediates cold- and menthol-induced histamine release in mast cells. Here, we report that TRPM8 is expressed in the basophilic leukemia mast cell line, RBL-2H3, and that exposure to menthol or low temperatures induced Ca(2+) influx in ... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4065663 Wed, 06 Oct 2010 23:00:00 +0100 4065663 http://www.medworm.com/index.php?rid=4065665&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932574%26dopt%3DAbstract Authors: Collado-Hilly M, Shirvani H, Jaillard D, Mauger JP The spatial organisation of the Ca(2+) signal in microdomains enables the regulation of various processes in specific regions of the cell and is essential for the versatility of cell responses to various stimuli. Ca(2+) signals can be independently regulated in the cytoplasm and in the nucleoplasm. Increases in the concentration of Ca(2+) in the nucleus can have specific effects different from those due to increases of Ca(2+) in the cytoplasm. We investigated the influence of cell polarity on the subcellular distribution of molecules responsible for intracellular Ca(2+) homeostasis (Ca(2+) release channels, Ca(2+) pumps and Ca(2+) binding proteins) and its influence on the intracellular Ca(2+) signal in MDCK cells with respect... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4065665 Mon, 04 Oct 2010 23:00:00 +0100 4065665 http://www.medworm.com/index.php?rid=4065664&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932575%26dopt%3DAbstract Authors: Raizman I, De Croos JN, Pilliar R, Kandel RA A single application of cyclic compression (1kPa, 1Hz, 30min) to bioengineered cartilage results in improved tissue formation through sequential catabolic and anabolic changes mediated via cell shape changes that are regulated by α5β1 integrin and membrane-type metalloprotease (MT1-MMP). To determine if calcium was involved in this process, the role of calcium in regulating cell shape changes, MT1-MMP expression and integrin activity in response to mechanical stimulation was examined. Stimulation-induced changes in cell shape and MT1-MMP expression were abolished by chelation of extracellular calcium, and this effect was reversed by re-introduction of calcium. Spreading was inhibited by blocking stretch-activated channels (with ga... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4065664 Mon, 04 Oct 2010 23:00:00 +0100 4065664 http://www.medworm.com/index.php?rid=4065667&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20926133%26dopt%3DAbstract This study indicates that I(min) channels are specifically regulated by Homer proteins in A431 cells. PMID: 20926133 [PubMed - as supplied by publisher] (Source: Cell Calcium) Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4065667 Sun, 03 Oct 2010 23:00:00 +0100 4065667 http://www.medworm.com/index.php?rid=4065666&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20926134%26dopt%3DAbstract Authors: Palygin O, Lalo U, Verkhratsky A, Pankratov Y Local, global and propagating calcium (Ca(2+)) signals provide the substrate for glial excitability. Here we analyse Ca(2+) permeability of NMDA and P2X(1/5) receptors expressed in cortical astrocytes and provide evidence that activation of these receptors trigger astroglial Ca(2+) signals when stimulated by either endogenous agonists or by synaptic release of neurotransmitters. The Ca(2+) permeability of the ionotropic receptors was determined by reversal potential shift analysis; the permeability ratio P(Ca)/P(K) was 3.1 for NMDA receptors and 2.2 for P2X(1/5) receptors. Selective stimulation of ionotropic receptors (with NMDA and α,β-methyleneATP) in freshly isolated cortical astrocytes induced ion currents associated with tra... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4065666 Sun, 03 Oct 2010 23:00:00 +0100 4065666 http://www.medworm.com/index.php?rid=4045675&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20888635%26dopt%3DAbstract Authors: Robinson P, Etheridge S, Song L, Armenise P, Jones OT, Fitzgerald EM Voltage-gated calcium channels (Ca(v)s) comprise a pore-forming α(1) with auxiliary α(2)δ and β subunits which modulate Ca(v) function and surface expression. Ca(v)α(1) and α(2)δ are present in signalling complexes termed lipid rafts but it is unclear whether α(2)δ is obligatory for targeting Ca(v)s to rafts or to what extent this influences cell surface organisation of Ca(v)s. Here, we have used imaging, biochemistry and electrophysiology to determine localisation and raft-partitioning of WT and functionally active HA-epitope tagged α(2)δ-1 and Ca(v)2.2 subunits expressed in COS-7 cells. We show that α(2)δ-1 not only partitions into lipid rafts itself but also mediates raft-partitioning of Ca(v)... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4045675 Wed, 29 Sep 2010 23:00:00 +0100 4045675 http://www.medworm.com/index.php?rid=4045676&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20888042%26dopt%3DAbstract Authors: Mills E, Pham E, Truong K The Rho proteins are important regulators of cell morphology, and the prototypical protein RhoA is known to regulate contraction, blebbing and bleb retraction. We have identified and experimentally confirmed that RhoA has a binding site for calmodulin, a ubiquitous transducer of the Ca(2+) second messenger. Using structural modeling, a fusion protein was designed wherein RhoA activity was controlled by Ca(2+) via calmodulin. Living cells transfected with this synthetic protein underwent Ca(2+) sensitive and calmodulin-dependent bleb retraction within minutes. Further, the modularity of Ca(2+) signaling was exploited to induce bleb retraction in response to blue light (using channelrhodopsin-2) or exogenous chemicals (with acetylcholine receptor), show... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=4045676 Tue, 28 Sep 2010 23:00:00 +0100 4045676 http://www.medworm.com/index.php?rid=3982265&cid=s_35394_171_f&fid=35394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20846719%26dopt%3DAbstract Authors: Koike C, Numata T, Ueda H, Mori Y, Furukawa T The transient receptor potential (TRP) channels affect essential functions widely in sensory systems of various species, both invertebrates and vertebrates. The channel protein encoded by the trp gene, the first identified TRP superfamily molecule, is known to mediate the Drosophila light response. A vertebrate TRP channel playing a crucial role in the visual system has not yet been discovered, although numerous studies have revealed primal functions of TRP superfamily molecules in various sensory systems other than vision. In the retina, which is the entry tissue in the vertebrate visual pathway, the transduction cation channel in ON bipolar cells has been elusive, despite intensive investigation by many researchers over a long pe... Cell Calcium journals http://www.medworm.com/rss/comments.php?id=3982265 Mon, 13 Sep 2010 23:00:00 +0100 3982265