Artículos de revistas: "Store Operated Calcium Channels"

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Parekh, Anant B. y James W. Putney. "Store-Operated Calcium Channels". Physiological Reviews 85, n.º 2 (abril de 2005): 757–810. http://dx.doi.org/10.1152/physrev.00057.2003.

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In electrically nonexcitable cells, Ca2+influx is essential for regulating a host of kinetically distinct processes involving exocytosis, enzyme control, gene regulation, cell growth and proliferation, and apoptosis. The major Ca2+entry pathway in these cells is the store-operated one, in which the emptying of intracellular Ca2+stores activates Ca2+influx (store-operated Ca2+entry, or capacitative Ca2+entry). Several biophysically distinct store-operated currents have been reported, but the best characterized is the Ca2+release-activated Ca2+current, ICRAC. Although it was initially considered to function only in nonexcitable cells, growing evidence now points towards a central role for ICRAC-like currents in excitable cells too. In spite of intense research, the signal that relays the store Ca2+content to CRAC channels in the plasma membrane, as well as the molecular identity of the Ca2+sensor within the stores, remains elusive. Resolution of these issues would be greatly helped by the identification of the CRAC channel gene. In some systems, evidence suggests that store-operated channels might be related to TRP homologs, although no consensus has yet been reached. Better understood are mechanisms that inactivate store-operated entry and hence control the overall duration of Ca2+entry. Recent work has revealed a central role for mitochondria in the regulation of ICRAC, and this is particularly prominent under physiological conditions. ICRACtherefore represents a dynamic interplay between endoplasmic reticulum, mitochondria, and plasma membrane. In this review, we describe the key electrophysiological features of ICRACand other store-operated Ca2+currents and how they are regulated, and we consider recent advances that have shed insight into the molecular mechanisms involved in this ubiquitous and vital Ca2+entry pathway.

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Prakriya, Murali y Richard S. Lewis. "Store-Operated Calcium Channels". Physiological Reviews 95, n.º 4 (octubre de 2015): 1383–436. http://dx.doi.org/10.1152/physrev.00020.2014.

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Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca2+ from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca2+ sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca2+ from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca2+ depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease.

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Bennett, Brian D., Ulises Alvarez y Keith A. Hruska. "Receptor-Operated Osteoclast Calcium Sensing*". Endocrinology 142, n.º 5 (1 de mayo de 2001): 1968–74. http://dx.doi.org/10.1210/endo.142.5.8125.

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Abstract Osteoclasts “sense” elevated extracellular calcium, which leads to cytoskeletal changes that may be linked to phospholipase C (PLC) activation and the associated rise in intracellular calcium ([Ca2+]i). Since PLC is linked to transient receptor potential channels (trp), we hypothesized that receptor activated calcium influx due to this channel type would be activated by osteoclasts sensing [Ca2+]e. We found that high [Ca2+]e induced similar intracellular Ca2+ rises in chicken osteoclasts with or without intracellular Ca2+ store depletion by either TPEN or thapsigargin, thus defining store-insensitive Ca2+ influx. This store-insensitive calcium sensing component was blocked by the PLC antagonist U73122. Also, the calcium channel inhibitor SKF 96365, a blocker of store-independent trp-like channels, was effective in inhibiting calcium sensing in the presence of thapsigargin. Thus, a store-independent component of calcium sensing was associated with ion channels linked to PLC. Since receptor activated transient receptor potential (trp) family cation channels open in a PLC-dependent and store-independent manner, we suggest that receptor operated channels are activated in osteoclasts stimulated by high extracellular Ca2+.

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4

Smyth, Jeremy T. y James W. Putney. "Regulation of store-operated calcium entry during cell division". Biochemical Society Transactions 40, n.º 1 (19 de enero de 2012): 119–23. http://dx.doi.org/10.1042/bst20110612.

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Store-operate Ca2+ channels gate Ca2+ entry into the cytoplasm in response to the depletion of Ca2+ from endoplasmic reticulum Ca2+ stores. The major molecular components of store-operated Ca2+ entry are STIM (stromal-interacting molecule) 1 (and in some instances STIM2) that serves as the endoplasmic reticulum Ca2+ sensor, and Orai (Orai1, Orai2 and Orai3) which function as pore-forming subunits of the store-operated channel. It has been known for some time that store-operated Ca2+ entry is shut down during cell division. Recent work has revealed complex mechanisms regulating the functions and locations of both STIM1 and Orai1 in dividing cells.

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Scott, Cameron C., Wendy Furuya, William S. Trimble y Sergio Grinstein. "Activation of Store-operated Calcium Channels". Journal of Biological Chemistry 278, n.º 33 (21 de mayo de 2003): 30534–39. http://dx.doi.org/10.1074/jbc.m304718200.

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6

Putney, J. W. "Pharmacology of Store-operated Calcium Channels". Molecular Interventions 10, n.º 4 (1 de agosto de 2010): 209–18. http://dx.doi.org/10.1124/mi.10.4.4.

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7

Parekh, A. B. y R. Penner. "Store depletion and calcium influx". Physiological Reviews 77, n.º 4 (1 de octubre de 1997): 901–30. http://dx.doi.org/10.1152/physrev.1997.77.4.901.

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Calcium influx in nonexcitable cells regulates such diverse processes as exocytosis, contraction, enzyme control, gene regulation, cell proliferation, and apoptosis. The dominant Ca2+ entry pathway in these cells is the store-operated one, in which Ca2+ entry is governed by the Ca2+ content of the agonist-sensitive intracellular Ca2+ stores. Only recently has a Ca2+ current been described that is activated by store depletion. The properties of this new current, called Ca2+ release-activated Ca2+ current (ICRAC), have been investigated in detail using the patch-clamp technique. Despite intense research, the nature of the signal that couples Ca2+ store content to the Ca2+ channels in the plasma membrane has remained elusive. Although ICRAC appears to be the most effective and widespread influx pathway, other store-operated currents have also been observed. Although the Ca2+ release-activated Ca2+ channel has not yet been cloned, evidence continues to accumulate that the Drosophila trp gene might encode a store-operated Ca2+ channel. In this review, we describe the historical development of the field of Ca2+ signaling and the discovery of store-operated Ca2+ currents. We focus on the electrophysiological properties of the prototype store-operated current ICRAC, discuss the regulatory mechanisms that control it, and finally consider recent advances toward the identification of molecular mechanisms involved in this ubiquitous and important Ca2+ entry pathway.

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8

Gusev, Konstantin, Lyuba Glouchankova, Alexander Zubov, Elena Kaznacheyeva, Zhengnan Wang, Ilya Bezprozvanny y Galina N. Mozhayeva. "The Store-operated Calcium Entry Pathways in Human Carcinoma A431 Cells". Journal of General Physiology 122, n.º 1 (30 de junio de 2003): 81–94. http://dx.doi.org/10.1085/jgp.200308815.

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Activation of phospholipase C (PLC)-mediated signaling pathways in nonexcitable cells causes the release of Ca2+ from intracellular Ca2+ stores and activation of Ca2+ influx across the plasma membrane. Two types of Ca2+ channels, highly Ca2+–selective ICRAC and moderately Ca2+–selective ISOC, support store-operated Ca2+ entry process. In previous patch-clamp experiments with a human carcinoma A431 cell line we described store-operated Imin/ICRACL plasma membrane Ca2+ influx channels. In the present paper we use whole-cell and single-channel recordings to further characterize store-operated Ca2+ influx pathways in A431 cells. We discovered that (a) ICRAC and ISOC are present in A431 cells; (b) ICRAC currents are highly selective for divalent cations and fully activate within 150 s after initiation of Ca2+ store depletion; (c) ISOC currents are moderately selective for divalent cations (PBa/PCs = 14.5) and require at least 300 s for full activation; (d) ICRAC and ISOC currents are activated by PLC-coupled receptor agonists; (e) ISOC currents are supported by Imin/ICRACL channels that display 8.5–10 pS conductance for sodium; (f) ICRAC single channel conductance for sodium is estimated at 0.9 pS by the noise analysis; (g) Imin/ICRACL channels are activated in excised patches by an amino-terminal fragment of InsP3R1 (InsP3R1N); and (h) InsP3 binding to InsP3R1N is necessary for activation of Imin/ICRACL channels. Our findings provide novel information about store-operated Ca2+ influx pathways in A431 cells.

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Zweifach, A. y R. S. Lewis. "Calcium-dependent potentiation of store-operated calcium channels in T lymphocytes." Journal of General Physiology 107, n.º 5 (1 de mayo de 1996): 597–610. http://dx.doi.org/10.1085/jgp.107.5.597.

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The depletion of intracellular Ca2+ stores triggers the opening of Ca2+ release-activated Ca2+ (CRAC) channels in the plasma membrane of T lymphocytes. We have investigated the additional role of extracellular Ca2+ (Ca02+) in promoting CRAC channel activation in Jurkat leukemic T cells. Ca2+ stores were depleted with 1 microM thapsigargin in the nominal absence of Ca02+ with 12 mM EGTA or BAPTA in the recording pipette. Subsequent application of Ca02+ caused ICRAC to appear in two phases. The initial phase was complete within 1 s and reflects channels that were open in the absence of Ca02+. The second phase consisted of a severalfold exponential increase in current amplitude with a time constant of 5-10 s; we call this increase Ca(2+)-dependent potentiation, or CDP. The shape of the current-voltage relation and the inferred single-channel current amplitude are unchanged during CDP, indicating that CDP reflects an alteration in channel gating rather than permeation. The extent of CDP is modulated by voltage, increasing from approximately 50% at +50 mV to approximately 350% at -75 mV in the presence of 2 mM Ca02+. The voltage dependence of CDP also causes ICRAC to increase slowly during prolonged hyperpolarizations in the constant presence of Ca02+. CDP is not affected by exogenous intracellular Ca2+ buffers, and Ni2+, a CRAC channel blocker, can cause potentiation. Thus, the underlying Ca2+ binding site is not intracellular. Ba2+ has little or no ability to potentiate CRAC channels. These results demonstrate that the store-depletion signal by itself triggers only a small fraction of capacitative Ca2+ entry and establish Ca2+ as a potent cofactor in this process. CDP confers a previously unrecognized voltage dependence and slow time dependence on CRAC channel activation that may contribute to the dynamic behavior of ICRAC.

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10

Norwood, Natalie, Timothy M. Moore, David A. Dean, Rakesh Bhattacharjee, Ming Li y Troy Stevens. "Store-operated calcium entry and increased endothelial cell permeability". American Journal of Physiology-Lung Cellular and Molecular Physiology 279, n.º 5 (1 de noviembre de 2000): L815—L824. http://dx.doi.org/10.1152/ajplung.2000.279.5.l815.

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We hypothesized that myosin light chain kinase (MLCK) links calcium release to activation of store-operated calcium entry, which is important for control of the endothelial cell barrier. Acute inhibition of MLCK caused calcium release from inositol trisphosphate-sensitive calcium stores and prevented subsequent activation of store-operated calcium entry by thapsigargin, suggesting that MLCK serves as an important mechanism linking store depletion to activation of membrane calcium channels. Moreover, in voltage-clamped single rat pulmonary artery endothelial cells, thapsigargin activated an inward calcium current that was abolished by MLCK inhibition. F-actin disruption activated a calcium current, and F-actin stabilization eliminated the thapsigargin-induced current. Thapsigargin increased endothelial cell permeability in the presence, but not in the absence, of extracellular calcium, indicating the importance of calcium entry in decreasing barrier function. Although MLCK inhibition prevented thapsigargin from stimulating calcium entry, it did not prevent thapsigargin from increasing permeability. Rather, inhibition of MLCK activity increased permeability that was especially prominent in low extracellular calcium. In conclusion, MLCK links store depletion to activation of a store-operated calcium entry channel. However, inhibition of calcium entry by MLCK is not sufficient to prevent thapsigargin from increasing endothelial cell permeability.

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11

Putney, James W., Natacha Steinckwich-Besançon, Takuro Numaga-Tomita, Felicity M. Davis, Pooja N. Desai, Diane M. D'Agostin, Shilan Wu y Gary S. Bird. "The functions of store-operated calcium channels". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1864, n.º 6 (junio de 2017): 900–906. http://dx.doi.org/10.1016/j.bbamcr.2016.11.028.

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12

Shuttleworth, T. J. y O. Mignen. "Calcium entry and the control of calcium oscillations". Biochemical Society Transactions 31, n.º 5 (1 de octubre de 2003): 916–19. http://dx.doi.org/10.1042/bst0310916.

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During oscillatory Ca2+ signals, the agonist-induced enhanced entry of extracellular Ca2+ plays a critical role in modulating the frequency of the oscillations. Although it was originally assumed that the entry of Ca2+ under these conditions occurred via the well-known, and apparently ubiquitous, store-operated mechanism, subsequent studies suggested that this was unlikely. It is now known that, in many cell types, a novel non-capacitative Ca2+-selective pathway whose activation is dependent on arachidonic acid is responsible, and the channels involved [ARC channels (arachidonate-regulated Ca2+ channels)] have been characterized. These ARC channels co-exist with the store-operated CRAC channels (Ca2+-release-activated Ca2+ channel) in cells, but each plays a unique and non-overlapping role in Ca2+ signalling. In particular, it is the ARC channels that are specifically activated at the low agonist concentrations that give rise to oscillatory Ca2+ signals and provide the predominant mode of Ca2+ entry under these conditions. The indications are that Ca2+ entry through the ARC channels increases the likelihood that low concentrations of Ins(1,4,5)P3 will trigger repetitive Ca2+ release. At higher agonist concentrations, store-depletion is more complete and sustained resulting in the activation of CRAC channels. At the same time the ARC channels are turned off, resulting in what we have described as a reciprocal regulation of these two distinct Ca2+ entry pathways.

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13

Ambudkar, I. S. "TRPC1: a core component of store-operated calcium channels". Biochemical Society Transactions 35, n.º 1 (22 de enero de 2007): 96–100. http://dx.doi.org/10.1042/bst0350096.

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The TRPC (transient receptor potential canonical) proteins are activated in response to agonist-stimulated PIP2 (phosphatidylinositol 4,5-bisphosphate) hydrolysis and have been suggested as candidate components of the elusive SOC (store-operated calcium channel). TRPC1 is currently the strongest candidate component of SOC. Endogenous TRPC1 has been shown to contribute to SOCE (store-operated calcium entry) in several different cell types. However, the mechanisms involved in the regulation of TRPC1 and its exact physiological function have yet to be established. Studies from our laboratory and several others have demonstrated that TRPC1 is assembled in a signalling complex with key calcium signalling proteins in functionally specific plasma membrane microdomains. Furthermore, critical interactions between TRPC1 monomers as well as interactions between TRPC1 and other proteins determine the surface expression and function of TRPC1-containing channels. Recent studies have revealed novel regulators of TRPC1-containing SOCs and have demonstrated a common molecular basis for the regulation of CRAC (calcium-release-activated calcium) and SOC channels. In the present paper, we will revisit the role of TRPC1 in SOCE and discuss how studies with TRPC1 provide an experimental basis for validating the mechanism of SOCE.

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14

Chen, Nanjun y Qigeng Fang. "Review the Regulation of Plasma Membrane Calcium Channel in Cancer and Patch Clamp Technique". E3S Web of Conferences 271 (2021): 04037. http://dx.doi.org/10.1051/e3sconf/202127104037.

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As one of the most versatile and universal second messengers, calcium plays an essential role in cell life. Here we briefly reviewed the research progress of how different calcium channels are located at the cell plasma membrane, including voltage-gated calcium channels (VGCCs), receptor-operated channels (ROC), and store-operated channels (ROC). These channels can regulate different cancer progression. Afterward, the patch clamp technique's development and operating principle, an important quantitative method used for ion channel investigation, are introduced in this paper.

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15

Xu, Ningyong, Donna L. Cioffi, Mikhail Alexeyev, Thomas C. Rich y Troy Stevens. "Sodium entry through endothelial store-operated calcium entry channels: regulation by Orai1". American Journal of Physiology-Cell Physiology 308, n.º 4 (15 de febrero de 2015): C277—C288. http://dx.doi.org/10.1152/ajpcell.00063.2014.

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Orai1 interacts with transient receptor potential protein of the canonical subfamily (TRPC4) and contributes to calcium selectivity of the endothelial cell store-operated calcium entry current ( ISOC). Orai1 silencing increases sodium permeability and decreases membrane-associated calcium, although it is not known whether Orai1 is an important determinant of cytosolic sodium transitions. We test the hypothesis that, upon activation of store-operated calcium entry channels, Orai1 is a critical determinant of cytosolic sodium transitions. Activation of store-operated calcium entry channels transiently increased cytosolic calcium and sodium, characteristic of release from an intracellular store. The sodium response occurred more abruptly and returned to baseline more rapidly than did the transient calcium rise. Extracellular choline substitution for sodium did not inhibit the response, although 2-aminoethoxydiphenyl borate and YM-58483 reduced it by ∼50%. After this transient response, cytosolic sodium continued to increase due to influx through activated store-operated calcium entry channels. The magnitude of this sustained increase in cytosolic sodium was greater when experiments were conducted in low extracellular calcium and when Orai1 expression was silenced; these two interventions were not additive, suggesting a common mechanism. 2-Aminoethoxydiphenyl borate and YM-58483 inhibited the sustained increase in cytosolic sodium, only in the presence of Orai1. These studies demonstrate that sodium permeates activated store-operated calcium entry channels, resulting in an increase in cytosolic sodium; the magnitude of this response is determined by Orai1.

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Vigont, V. A., O. A. Zimina, L. N. Glushankova, J. A. Kolobkova, M. A. Ryazantseva, G. N. Mozhayeva y E. V. Kaznacheyeva. "STIM1 Protein Activates Store-Operated Calcium Channels in Cellular Model of Huntington’s Disease". Acta Naturae 6, n.º 4 (15 de diciembre de 2014): 40–47. http://dx.doi.org/10.32607/20758251-2014-6-4-40-47.

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We have shown that the expression of full-length mutated huntingtin in human neuroblastoma cells (SK-N-SH) leads to an abnormal increase in calcium entry through store-operated channels. In this paper, the expression of the N-terminal fragment of mutated huntingtin (Htt138Q-1exon) is shown to be enough to provide an actual model for Huntingtons disease. We have shown that Htt138Q-1exon expression causes increased store-operated calcium entry, which is mediated by at least two types of channels in SK-N-SH cells with different reversal potentials. Calcium sensor, STIM1, is required for activation of store-operated calcium entry in these cells. The results provide grounds for considering the proteins responsible for the activation and maintenance of the store-operated calcium entry as promising targets for developing novel therapeutics for neurodegenerative diseases.

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Harper, Jacquie L. y John W. Daly. "Store-operated calcium channels in HL-60 cells". Life Sciences 67, n.º 6 (junio de 2000): 651–62. http://dx.doi.org/10.1016/s0024-3205(00)00659-7.

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18

CHANG, Wei-chiao. "Store-operated calcium channels and pro-inflammatory signals". Acta Pharmacologica Sinica 27, n.º 7 (julio de 2006): 813–20. http://dx.doi.org/10.1111/j.1745-7254.2006.00395.x.

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19

Bakowski, Daniel, Fraser Murray y Anant B. Parekh. "Store-Operated Ca2+ Channels: Mechanism, Function, Pharmacology, and Therapeutic Targets". Annual Review of Pharmacology and Toxicology 61, n.º 1 (6 de enero de 2021): 629–54. http://dx.doi.org/10.1146/annurev-pharmtox-031620-105135.

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Calcium (Ca2+) release–activated Ca2+ (CRAC) channels are a major route for Ca2+ entry in eukaryotic cells. These channels are store operated, opening when the endoplasmic reticulum (ER) is depleted of Ca2+, and are composed of the ER Ca2+ sensor protein STIM and the pore-forming plasma membrane subunit Orai. Recent years have heralded major strides in our understanding of the structure, gating, and function of the channels. Loss-of-function and gain-of-function mutants combined with RNAi knockdown strategies have revealed important roles for the channel in numerous human diseases, making the channel a clinically relevant target. Drugs targeting the channels generally lack specificity or exhibit poor efficacy in animal models. However, the landscape is changing, and CRAC channel blockers are now entering clinical trials. Here, we describe the key molecular and biological features of CRAC channels, consider various diseases associated with aberrant channel activity, and discuss targeting of the channels from a therapeutic perspective.

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20

Popugaeva, Elena. "Fine Tuning of Intracellular Ca2+ Content by Pharmacological Agents – A Strategy to Prevent Synapse Loss in Alzheimer Disease Hippocampal Neurons". Current Alzheimer Research 17, n.º 12 (22 de febrero de 2021): 1065–71. http://dx.doi.org/10.2174/1567205018666210119145735.

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: Alzheimer disease is the dominant form of elderly dementia. Today all clinical trials that target β-amyloid have failed to indicate that β-amyloid may not be a causative agent in AD pathogenesis. Thus there is a need to search for alternative ways to treat AD patients. : Neuronal store-operated calcium entry is a fine-tuning mechanism that regulates intracellular Ca2+ content. Recent evidence suggests that store-operated calcium channels may be targeted with pharmacological agents in order to prevent synapse loss, recover long-term potentiation and change behavior. : Current mini-review discusses basic chemical structures that modulate intracellular calcium dysbalance via targeting store-operated calcium channels and their applicability as anti-AD pharmacological agents.

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Zhu, Xi y Lutz Birnbaumer. "Calcium Channels Formed by Mammalian Trp Homologues". Physiology 13, n.º 5 (octubre de 1998): 211–17. http://dx.doi.org/10.1152/physiologyonline.1998.13.5.211.

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Homologues of Drosophila trp genes have been isolated from mammalian species in hope that they may constitute the molecular basis of capacitative Ca2+ entry. Expression of Trps suggests that they form Ca2+ influx channels regulated by either store depletion or a more upstream event. Store-operated Trp channels can be formed by heteromultimerization.

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22

Lis, Annette, Susanna Zierler, Christine Peinelt, Andrea Fleig y Reinhold Penner. "A single lysine in the N-terminal region of store-operated channels is critical for STIM1-mediated gating". Journal of General Physiology 136, n.º 6 (29 de noviembre de 2010): 673–86. http://dx.doi.org/10.1085/jgp.201010484.

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Store-operated Ca2+ entry is controlled by the interaction of stromal interaction molecules (STIMs) acting as endoplasmic reticulum ER Ca2+ sensors with calcium release–activated calcium (CRAC) channels (CRACM1/2/3 or Orai1/2/3) in the plasma membrane. Here, we report structural requirements of STIM1-mediated activation of CRACM1 and CRACM3 using truncations, point mutations, and CRACM1/CRACM3 chimeras. In accordance with previous studies, truncating the N-terminal region of CRACM1 or CRACM3 revealed a 20–amino acid stretch close to the plasma membrane important for channel gating. Exchanging the N-terminal region of CRACM3 with that of CRACM1 (CRACM3-N(M1)) results in accelerated kinetics and enhanced current amplitudes. Conversely, transplanting the N-terminal region of CRACM3 into CRACM1 (CRACM1-N(M3)) leads to severely reduced store-operated currents. Highly conserved amino acids (K85 in CRACM1 and K60 in CRACM3) in the N-terminal region close to the first transmembrane domain are crucial for STIM1-dependent gating of CRAC channels. Single-point mutations of this residue (K85E and K60E) eliminate store-operated currents induced by inositol 1,4,5-trisphosphate and reduce store-independent gating by 2-aminoethoxydiphenyl borate. However, short fragments of these mutant channels are still able to communicate with the CRAC-activating domain of STIM1. Collectively, these findings identify a single amino acid in the N terminus of CRAC channels as a critical element for store-operated gating of CRAC channels.

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Harper, J. L., Y. Shin y J. W. Daly. "Loperamide: A positive modulator for store-operated calcium channels?" Proceedings of the National Academy of Sciences 94, n.º 26 (23 de diciembre de 1997): 14912–17. http://dx.doi.org/10.1073/pnas.94.26.14912.

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Molnar, Tünde, Peter Barabas, Lutz Birnbaumer, Claudio Punzo, Vladimir Kefalov y David Križaj. "Store-operated channels regulate intracellular calcium in mammalian rods". Journal of Physiology 590, n.º 15 (16 de julio de 2012): 3465–81. http://dx.doi.org/10.1113/jphysiol.2012.234641.

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Parekh, Anant B. "On the activation mechanism of store-operated calcium channels". Pflügers Archiv - European Journal of Physiology 453, n.º 3 (21 de junio de 2006): 303–11. http://dx.doi.org/10.1007/s00424-006-0089-y.

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Skopin, Anton Yu, Andrey D. Grigoryev, Lyubov N. Glushankova, Alexey V. Shalygin, Guanghui Wang, Viktor G. Kartzev y Elena V. Kaznacheyeva. "A Novel Modulator of STIM2-Dependent Store-Operated Ca2+ Channel Activity". Acta Naturae 13, n.º 1 (15 de marzo de 2021): 140–46. http://dx.doi.org/10.32607/actanaturae.11269.

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Store-operated Ca2+ entry is one of the main pathways of calcium influx into non-excitable cells, which entails the initiation of many intracellular processes. The endoplasmic reticulum Ca2+ sensors STIM1 and STIM2 are the key components of store-operated Ca2+ entry in mammalian cells. Under physiological conditions, STIM proteins are responsible for store-operated Ca2+ entry activation. The STIM1 and STIM2 proteins differ in their potency for activating different store-operated channels. At the moment, there are no selective modulators of the STIM protein activity. We screened a library of small molecules and found the 4-MPTC compound, which selectively inhibited STIM2-dependent store-operated Ca2+ entry (IC50 = 1 M) and had almost no effect on the STIM1-dependent activation of store-operated channels.

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27

Zabłocki, K., A. Makowska y J. Duszyński. "Mitochondrial uncoupling does not influence the stability of the intracellular signal activating plasma membrane calcium channels." Acta Biochimica Polonica 48, n.º 1 (31 de marzo de 2001): 157–61. http://dx.doi.org/10.18388/abp.2001_5122.

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The effects of various concentrations of thapsigargin, a specific inhibitor of Ca2+-ATPase in the endoplasmic reticulum (ER) membrane, on calcium homeostasis in lymphoidal T cells (Jurkat) were investigated. Preincubation of these cells suspended in nominally calcium-free medium with 0.1 microM thapsigargin resulted in a complete release of Ca2+ from intracellular calcium stores. When the medium was supplemented with 3 mM CaCl2 the cells maintained constantly elevated level of cytosolic Ca2+. However, thapsigargin applied at lower concentration produced only a partial depletion of the stores. For example, in the cells pretreated with 1 nM thapsigargin and suspended in calcium-free medium approximately 75% of the calcium content was released from the intracellular stores. The addition of 3 mM CaCl2 to such cell suspension led to a transient increase in cytosolic calcium concentration, followed by a return to a lower steady-state. This phenomenon, related to the refilling of the ER by Ca2+, allowed to estimate the half-time for the process of cell recovery after activation of store-operated calcium channels. By this approach we have found that carbonyl cyanide m-chlorophenylhydrazone, which has been documented to inhibit calcium entry into Jurkat cells, does not influence the stability of the intracellular signal involved in the activation of store-operated calcium channels.

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Chen, Xingjuan, Ruiyuan Cao y Wu Zhong. "Host Calcium Channels and Pumps in Viral Infections". Cells 9, n.º 1 (30 de diciembre de 2019): 94. http://dx.doi.org/10.3390/cells9010094.

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Ca2+ is essential for virus entry, viral gene replication, virion maturation, and release. The alteration of host cells Ca2+ homeostasis is one of the strategies that viruses use to modulate host cells signal transduction mechanisms in their favor. Host calcium-permeable channels and pumps (including voltage-gated calcium channels, store-operated channels, receptor-operated channels, transient receptor potential ion channels, and Ca2+-ATPase) mediate Ca2+ across the plasma membrane or subcellular organelles, modulating intracellular free Ca2+. Therefore, these Ca2+ channels or pumps present important aspects of viral pathogenesis and virus–host interaction. It has been reported that viruses hijack host calcium channels or pumps, disturbing the cellular homeostatic balance of Ca2+. Such a disturbance benefits virus lifecycles while inducing host cells’ morbidity. Evidence has emerged that pharmacologically targeting the calcium channel or calcium release from the endoplasmic reticulum (ER) can obstruct virus lifecycles. Impeding virus-induced abnormal intracellular Ca2+ homeostasis is becoming a useful strategy in the development of potent antiviral drugs. In this present review, the recent identified cellular calcium channels and pumps as targets for virus attack are emphasized.

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29

Hoth, Markus, Christopher M. Fanger y Richard S. Lewis. "Mitochondrial Regulation of Store-operated Calcium Signaling in T Lymphocytes". Journal of Cell Biology 137, n.º 3 (5 de mayo de 1997): 633–48. http://dx.doi.org/10.1083/jcb.137.3.633.

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Mitochondria act as potent buffers of intracellular Ca2+ in many cells, but a more active role in modulating the generation of Ca2+ signals is not well established. We have investigated the ability of mitochondria to modulate store-operated or “capacitative” Ca2+ entry in Jurkat leukemic T cells and human T lymphocytes using fluorescence imaging techniques. Depletion of the ER Ca2+ store with thapsigargin (TG) activates Ca2+ release-activated Ca2+ (CRAC) channels in T cells, and the ensuing influx of Ca2+ loads a TG- insensitive intracellular store that by several criteria appears to be mitochondria. Loading of this store is prevented by carbonyl cyanide m-chlorophenylhydrazone or by antimycin A1 + oligomycin, agents that are known to inhibit mitochondrial Ca2+ import by dissipating the mitochondrial membrane potential. Conversely, intracellular Na+ depletion, which inhibits Na+-dependent Ca2+ export from mitochondria, enhances store loading. In addition, we find that rhod-2 labels mitochondria in T cells, and it reports changes in Ca2+ levels that are consistent with its localization in the TG-insensitive store. Ca2+ uptake by the mitochondrial store is sensitive (threshold is <400 nM cytosolic Ca2+), rapid (detectable within 8 s), and does not readily saturate. The rate of mitochondrial Ca2+ uptake is sensitive to extracellular [Ca2+], indicating that mitochondria sense Ca2+ gradients near CRAC channels. Remarkably, mitochondrial uncouplers or Na+ depletion prevent the ability of T cells to maintain a high rate of capacitative Ca2+ entry over prolonged periods of >10 min. Under these conditions, the rate of Ca2+ influx in single cells undergoes abrupt transitions from a high influx to a low influx state. These results demonstrate that mitochondria not only buffer the Ca2+ that enters T cells via store-operated Ca2+ channels, but also play an active role in modulating the rate of capacitative Ca2+ entry.

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30

Treves, Susan, Clara Franzini-Armstrong, Luca Moccagatta, Christophe Arnoult, Cristiano Grasso, Adam Schrum, Sylvie Ducreux et al. "Junctate is a key element in calcium entry induced by activation of InsP3 receptors and/or calcium store depletion". Journal of Cell Biology 166, n.º 4 (9 de agosto de 2004): 537–48. http://dx.doi.org/10.1083/jcb.200404079.

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In many cell types agonist-receptor activation leads to a rapid and transient release of Ca2+ from intracellular stores via activation of inositol 1,4,5 trisphosphate (InsP3) receptors (InsP3Rs). Stimulated cells activate store- or receptor-operated calcium channels localized in the plasma membrane, allowing entry of extracellular calcium into the cytoplasm, and thus replenishment of intracellular calcium stores. Calcium entry must be finely regulated in order to prevent an excessive intracellular calcium increase. Junctate, an integral calcium binding protein of endo(sarco)plasmic reticulum membrane, (a) induces and/or stabilizes peripheral couplings between the ER and the plasma membrane, and (b) forms a supramolecular complex with the InsP3R and the canonical transient receptor potential protein (TRPC) 3 calcium entry channel. The full-length protein modulates both agonist-induced and store depletion–induced calcium entry, whereas its NH2 terminus affects receptor-activated calcium entry. RNA interference to deplete cells of endogenous junctate, knocked down both agonist-activated calcium release from intracellular stores and calcium entry via TRPC3. These results demonstrate that junctate is a new protein involved in calcium homeostasis in eukaryotic cells.

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31

Davis, Felicity M., Agnes Janoshazi, Kyathanahalli S. Janardhan, Natacha Steinckwich, Diane M. D’Agostin, John G. Petranka, Pooja N. Desai et al. "Essential role of Orai1 store-operated calcium channels in lactation". Proceedings of the National Academy of Sciences 112, n.º 18 (20 de abril de 2015): 5827–32. http://dx.doi.org/10.1073/pnas.1502264112.

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The nourishment of neonates by nursing is the defining characteristic of mammals. However, despite considerable research into the neural control of lactation, an understanding of the signaling mechanisms underlying the production and expulsion of milk by mammary epithelial cells during lactation remains largely unknown. Here we demonstrate that a store-operated Ca2+ channel subunit, Orai1, is required for both optimal Ca2+ transport into milk and for milk ejection. Using a novel, 3D imaging strategy, we visualized live oxytocin-induced alveolar unit contractions in the mammary gland, and we demonstrated that in this model milk is ejected by way of pulsatile contractions of these alveolar units. In mammary glands of Orai1 knockout mice, these contractions are infrequent and poorly coordinated. We reveal that oxytocin also induces a large transient release of stored Ca2+ in mammary myoepithelial cells followed by slow, irregular Ca2+ oscillations. These oscillations, and not the initial Ca2+ transient, are mediated exclusively by Orai1 and are absolutely required for milk ejection and pup survival, an observation that redefines the signaling processes responsible for milk ejection. These findings clearly demonstrate that Ca2+ is not just a substrate for nutritional enrichment in mammals but is also a master regulator of the spatiotemporal signaling events underpinning mammary alveolar unit contraction. Orai1-dependent Ca2+ oscillations may represent a conserved language in myoepithelial cells of other secretory epithelia, such as sweat glands, potentially shedding light on other Orai1 channelopathies, including anhidrosis (an inability to sweat).

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32

Montaño, Luis M. y Blanca Bazán-Perkins. "Resting calcium influx in airway smooth muscle". Canadian Journal of Physiology and Pharmacology 83, n.º 8-9 (1 de agosto de 2005): 717–23. http://dx.doi.org/10.1139/y05-063.

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Plasma membrane Ca2+ leak remains the most uncertain of the cellular Ca2+ regulation pathways. During passive Ca2+ influx in non-stimulated smooth muscle cells, basal activity of constitutive Ca2+ channels seems to be involved. In vascular smooth muscle, the 3 following Ca2+ entry pathways contribute to this phenomenon: (i) via voltage-dependent Ca2+ channels, (ii) receptor gated Ca2+ channels, and (iii) store operated Ca2+ channels, although, in airway smooth muscle it seems only 2 passive Ca2+ influx pathways are implicated, one sensitive to SKF 96365 (receptor gated Ca2+ channels) and the other to Ni2+ (store operated Ca2+ channels). Resting Ca2+ entry could provide a sufficient amount of Ca2+ and contribute to resting intracellular Ca2+ concentration ([Ca2+]i), maintenance of the resting membrane potential, myogenic tone, and sarcoplasmic reticulum-Ca2+ refilling. However, further research, especially in airway smooth muscle, is required to better explore the physiological role of this passive Ca2+ influx pathway as it could be involved in airway hyperresponsiveness.Key words: basal Ca2+ entry, constitutive Ca2+ channels, airway and vascular smooth muscle, SKF 96365, Ni2+.

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33

Yeromin, Andriy V., Jack Roos, Kenneth A. Stauderman y Michael D. Cahalan. "A Store-operated Calcium Channel in Drosophila S2 Cells". Journal of General Physiology 123, n.º 2 (26 de enero de 2004): 167–82. http://dx.doi.org/10.1085/jgp.200308982.

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Using whole-cell recording in Drosophila S2 cells, we characterized a Ca2+-selective current that is activated by depletion of intracellular Ca2+ stores. Passive store depletion with a Ca2+-free pipette solution containing 12 mM BAPTA activated an inwardly rectifying Ca2+ current with a reversal potential >60 mV. Inward currents developed with a delay and reached a maximum of 20–50 pA at −110 mV. This current doubled in amplitude upon increasing external Ca2+ from 2 to 20 mM and was not affected by substitution of choline for Na+. A pipette solution containing ∼300 nM free Ca2+ and 10 mM EGTA prevented spontaneous activation, but Ca2+ current activated promptly upon application of ionomycin or thapsigargin, or during dialysis with IP3. Isotonic substitution of 20 mM Ca2+ by test divalent cations revealed a selectivity sequence of Ba2+ > Sr2+ > Ca2+ >> Mg2+. Ba2+ and Sr2+ currents inactivated within seconds of exposure to zero-Ca2+ solution at a holding potential of 10 mV. Inactivation of Ba2+ and Sr2+ currents showed recovery during strong hyperpolarizing pulses. Noise analysis provided an estimate of unitary conductance values in 20 mM Ca2+ and Ba2+ of 36 and 420 fS, respectively. Upon removal of all external divalent ions, a transient monovalent current exhibited strong selectivity for Na+ over Cs+. The Ca2+ current was completely and reversibly blocked by Gd3+, with an IC50 value of ∼50 nM, and was also blocked by 20 μM SKF 96365 and by 20 μM 2-APB. At concentrations between 5 and 14 μM, application of 2-APB increased the magnitude of Ca2+ currents. We conclude that S2 cells express store-operated Ca2+ channels with many of the same biophysical characteristics as CRAC channels in mammalian cells.

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34

Lewis, R. S. "Store-Operated Calcium Channels: New Perspectives on Mechanism and Function". Cold Spring Harbor Perspectives in Biology 3, n.º 12 (26 de julio de 2011): a003970. http://dx.doi.org/10.1101/cshperspect.a003970.

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35

McLarnon, J. G., J. Helm, V. Goghari, S. Franciosi, H. B. Choi, A. Nagai y S. U. Kim. "Anion channels modulate store-operated calcium influx in human microglia". Cell Calcium 28, n.º 4 (octubre de 2000): 261–68. http://dx.doi.org/10.1054/ceca.2000.0150.

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36

Ambudkar, Indu S., Hwei Ling Ong, Xibao Liu, Bidhan Bandyopadhyay y Kwong Tai Cheng. "TRPC1: The link between functionally distinct store-operated calcium channels". Cell Calcium 42, n.º 2 (agosto de 2007): 213–23. http://dx.doi.org/10.1016/j.ceca.2007.01.013.

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37

Bartoli, Fiona, Jessica Sabourin, Ana-Maria Gomez y Jean-Pierre Benitah. "Store Operated Calcium Channels, New Targets of Aldosterone in Cardiomyocytes". Biophysical Journal 110, n.º 3 (febrero de 2016): 611a. http://dx.doi.org/10.1016/j.bpj.2015.11.3264.

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38

Seo, Jong Bae, Mean-Hwan Kim, Bertil Hille y Duk-Su Koh. "Characterization of Store-Operated Calcium Channels in Pancreatic Duct Epithelia". Biophysical Journal 106, n.º 2 (enero de 2014): 317a. http://dx.doi.org/10.1016/j.bpj.2013.11.1833.

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39

Kerschbaum, Hubert H. y Michael D. Cahalan. "Monovalent Permeability, Rectification, and Ionic Block of Store-operated Calcium Channels in Jurkat T Lymphocytes". Journal of General Physiology 111, n.º 4 (1 de abril de 1998): 521–37. http://dx.doi.org/10.1085/jgp.111.4.521.

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We used whole-cell recording to characterize ion permeation, rectification, and block of monovalent current through calcium release-activated calcium (CRAC) channels in Jurkat T lymphocytes. Under physiological conditions, CRAC channels exhibit a high degree of selectivity for Ca2+, but can be induced to carry a slowly declining Na+ current when external divalent ions are reduced to micromolar levels. Using a series of organic cations as probes of varying size, we measured reversal potentials and calculated permeability ratios relative to Na+, PX/PNa, in order to estimate the diameter of the conducting pore. Ammonium (NH4+) exhibited the highest relative permeability (PNH4/PNa = 1.37). The largest permeant ion, tetramethylammonium with a diameter of 0.55 nm, had PTMA/PNa of 0.09. N-methyl-d-glucamine (0.50 × 0.64 × 1.20 nm) was not measurably permeant. In addition to carrying monovalent current, NH4+ reduced the slow decline of monovalent current (“inactivation”) upon lowering [Ca2+]o. This kinetic effect of extracellular NH4+ can be accounted for by an increase in intracellular pH (pHi), since raising intracellular pH above 8 reduced the extent of inactivation. In addition, decreasing pHi reduced monovalent and divalent current amplitudes through CRAC channels with a pKa of 6.8. In several channel types, Mg2+ has been shown to produce rectification by a voltage-dependent block mechanism. Mg2+ removal from the pipette solution permitted large outward monovalent currents to flow through CRAC channels while also increasing the channel's relative Cs+ conductance and eliminating the inactivation of monovalent current. Boltzmann fits indicate that intracellular Mg2+ contributes to inward rectification by blocking in a voltage-dependent manner, with a zδ product of 1.88. Ca2+ block from the outside was also found to be voltage dependent with zδ of 1.62. These experiments indicate that the CRAC channel, like voltage-gated Ca2+ channels, achieves selectivity for Ca2+ by selective binding in a large pore with current–voltage characteristics shaped by internal Mg2+.

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40

Dagan, Inbal y Raz Palty. "Regulation of Store-Operated Ca2+ Entry by SARAF". Cells 10, n.º 8 (26 de julio de 2021): 1887. http://dx.doi.org/10.3390/cells10081887.

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Calcium (Ca2+) signaling plays a dichotomous role in cellular biology, controlling cell survival and proliferation on the one hand and cellular toxicity and cell death on the other. Store-operated Ca2+ entry (SOCE) by CRAC channels represents a major pathway for Ca2+ entry in non-excitable cells. The CRAC channel has two key components, the endoplasmic reticulum Ca2+ sensor stromal interaction molecule (STIM) and the plasma-membrane Ca2+ channel Orai. Physical coupling between STIM and Orai opens the CRAC channel and the resulting Ca2+ flux is regulated by a negative feedback mechanism of slow Ca2+ dependent inactivation (SCDI). The identification of the SOCE-associated regulatory factor (SARAF) and investigations of its role in SCDI have led to new functional and molecular insights into how SOCE is controlled. In this review, we provide an overview of the functional and molecular mechanisms underlying SCDI and discuss how the interaction between SARAF, STIM1, and Orai1 shapes Ca2+ signaling in cells.

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41

Walsh, Ciara M., Mary K. Doherty, Alexei V. Tepikin y Robert D. Burgoyne. "Evidence for an interaction between Golli and STIM1 in store-operated calcium entry". Biochemical Journal 430, n.º 3 (27 de agosto de 2010): 453–60. http://dx.doi.org/10.1042/bj20100650.

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SOCCs (store-operated Ca2+ channels) are highly selective ion channels that are activated upon release of Ca2+ from intracellular stores to regulate a multitude of diverse cellular functions. It was reported previously that Golli-BG21, a member of the MBP (myelin basic protein) family of proteins, regulates SOCE (store-operated Ca2+ entry) in T-cells and oligodendrocyte precursor cells, but the underlying mechanism for this regulation is unknown. In the present study we have discovered that Golli can directly interact with the ER (endoplasmic reticulum) Ca2+-sensing protein STIM1 (stromal interaction molecule 1). Golli interacts with the C-terminal domain of STIM1 in both in vitro and in vivo binding assays and this interaction may be modulated by the intracellular Ca2+ concentration. Golli also co-localizes with full-length STIM1 and Orai1 complexes in HeLa cells following Ca2+ store depletion. Overexpression of Golli reduces SOCE in HeLa cells, but this inhibition is overcome by overexpressing STIM1. We therefore suggest that Golli binds to STIM1–Orai1 complexes to negatively regulate the activity of SOCCs.

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42

Fodor, János, Csaba Matta, Tamás Oláh, Tamás Juhász, Roland Takács, Adrienn Tóth, Beatrix Dienes, László Csernoch y Róza Zákány. "Store-operated calcium entry and calcium influx via voltage-operated calcium channels regulate intracellular calcium oscillations in chondrogenic cells". Cell Calcium 54, n.º 1 (julio de 2013): 1–16. http://dx.doi.org/10.1016/j.ceca.2013.03.003.

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43

Grabmayr, Herwig, Christoph Romanin y Marc Fahrner. "STIM Proteins: An Ever-Expanding Family". International Journal of Molecular Sciences 22, n.º 1 (31 de diciembre de 2020): 378. http://dx.doi.org/10.3390/ijms22010378.

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Stromal interaction molecules (STIM) are a distinct class of ubiquitously expressed single-pass transmembrane proteins in the endoplasmic reticulum (ER) membrane. Together with Orai ion channels in the plasma membrane (PM), they form the molecular basis of the calcium release-activated calcium (CRAC) channel. An intracellular signaling pathway known as store-operated calcium entry (SOCE) is critically dependent on the CRAC channel. The SOCE pathway is activated by the ligand-induced depletion of the ER calcium store. STIM proteins, acting as calcium sensors, subsequently sense this depletion and activate Orai ion channels via direct physical interaction to allow the influx of calcium ions for store refilling and downstream signaling processes. This review article is dedicated to the latest advances in the field of STIM proteins. New results of ongoing investigations based on the recently published functional data as well as structural data from nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations are reported and complemented with a discussion of the latest developments in the research of STIM protein isoforms and their differential functions in regulating SOCE.

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44

Ma, Rong, Sonja Smith, Angie Child, Pamela K. Carmines y Steven C. Sansom. "Store-operated Ca2+ channels in human glomerular mesangial cells". American Journal of Physiology-Renal Physiology 278, n.º 6 (1 de junio de 2000): F954—F961. http://dx.doi.org/10.1152/ajprenal.2000.278.6.f954.

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Experiments were performed to identify the biophysical properties of store-operated Ca2+ channels (SOC) in cultured human glomerular mesangial cells (MC). A fluorometric technique (fura 2) was utilized to monitor the change in intracellular calcium concentration ([Ca2+]i) evoked by elevating external [Ca2+] from 10 nM to 1 mM (Δ[Ca2+]). Under control conditions, Δ[Ca2+] averaged 6 nM and was unaffected by elevating bath [K+]. After treatment with 1 μM thapsigargin to deplete the intracellular Ca2+ store, the change in [Ca2+]i(Δ[Ca2+]th) averaged 147 ± 16 nM. In thapsigargin-treated MC studied under depolarizing conditions (75 mM bath K+), Δ[Ca2+]th was 45 ± 7 nM. The Δ[Ca2+]th response of thapsigargin-treated cells was inhibited by La3+(IC50 = 335 nM) but was unaffected by 5 μM Cd2+. In patch clamp studies, inward currents were observed in cell-attached patches with either 90 mM Ba2+ or Ca2+ in the pipette and 140 mM KCl in the bathing solution. The single-channel conductance was 2.1 pS with Ba2+ and 0.7 pS with Ca2+. The estimated selectivities were Ca2+ > Ba2+ >> K+. These channels were sensitive to 2 μM La3+, insensitive to 5 μM Cd2+, and voltage independent, with an average channel activity ( NP o) of 1.02 at command potential (− V p) ranging from 0 to −80 mV. In summary, MC exhibited an electrogenic Ca2+ influx pathway that is suggestive of Ca2+entry through SOC, as well as a small-conductance divalent-selective channel displaying biophysical properties consistent with SOC. Based on estimates of whole cell Ca2+ influx derived from our data, we conclude that SOC with low single-channel conductance must be highly abundant in MC to allow significant capacitative Ca2+ entry in response to depletion of the intracellular store.

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45

Segal, Menahem y Eduard Korkotian. "Roles of Calcium Stores and Store-Operated Channels in Plasticity of Dendritic Spines". Neuroscientist 22, n.º 5 (9 de julio de 2016): 477–85. http://dx.doi.org/10.1177/1073858415613277.

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46

Zhou, Anqi, Xijun Liu, Suxia Zhang y Bing Huo. "Effects of store-operated and receptor-operated calcium channels on synchronization of calcium oscillations in astrocytes". Biosystems 198 (diciembre de 2020): 104233. http://dx.doi.org/10.1016/j.biosystems.2020.104233.

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47

TURNER, Helen, Andrea FLEIG, Alexander STOKES, Jean-Pierre KINET y Reinhold PENNER. "Discrimination of intracellular calcium store subcompartments using TRPV1 (transient receptor potential channel, vanilloid subfamily member 1) release channel activity". Biochemical Journal 371, n.º 2 (15 de abril de 2003): 341–50. http://dx.doi.org/10.1042/bj20021381.

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The store-operated calcium-release-activated calcium current, ICRAC, is a major mechanism for calcium entry into non-excitable cells. ICRAC refills calcium stores and permits sustained calcium signalling. The relationship between inositol 1,4,5-trisphosphate receptor (InsP3R)-containing stores and ICRAC is not understood. A model of global InsP3R store depletion coupling with ICRAC activation may be simplistic, since intracellular stores are heterogeneous in their release and refilling activities. Here we use a ligand-gated calcium channel, TRPV1 (transient receptor potential channel, vanilloid subfamily member 1), as a new tool to probe store heterogeneity and define intracellular calcium compartments in a mast cell line. TRPV1 has activity as an intracellular release channel but does not mediate global calcium store depletion and does not invade a store coupled with ICRAC. Intracellular TRPV1 localizes to a subset of the InsP3R-containing stores. TRPV1 sensitivity functionally subdivides the InsP3-sensitive store, as does heterogeneity in the sarcoplasmic/endoplasmic-reticulum Ca2+-ATPase isoforms responsible for store refilling. These results provide unequivocal evidence that a specific ‘CRAC store’ exists within the InsP3-releasable calcium stores and describe a novel methodology for manipulation of intracellular free calcium.

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48

Marthan, Roger. "Store-operated calcium entry and intracellular calcium release channels in airway smooth muscle". American Journal of Physiology-Lung Cellular and Molecular Physiology 286, n.º 5 (mayo de 2004): L907—L908. http://dx.doi.org/10.1152/ajplung.00410.2003.

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49

Ma, Jianjie y Zui Pan. "Retrograde activation of store-operated calcium channel". Cell Calcium 33, n.º 5-6 (mayo de 2003): 375–84. http://dx.doi.org/10.1016/s0143-4160(03)00050-2.

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50

Morales, Sara, Pedro J. Camello, Soledad Alcón, Ginés M. Salido, Gary Mawe y María J. Pozo. "Coactivation of capacitative calcium entry and L-type calcium channels in guinea pig gallbladder". American Journal of Physiology-Gastrointestinal and Liver Physiology 286, n.º 6 (junio de 2004): G1090—G1100. http://dx.doi.org/10.1152/ajpgi.00260.2003.

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We have evaluated the presence of capacitative Ca2+ entry (CCE) in guinea pig gallbladder smooth muscle (GBSM), including a possible relation with activation of L-type Ca2+ channels. Changes in cytosolic Ca2+ concentration induced by Ca2+ entry were assessed by digital microfluorometry in isolated, fura 2-loaded GBSM cells. Application of thapsigargin, a specific inhibitor of the Ca2+ store pump, induced a transient Ca2+ release followed by sustained entry of extracellular Ca2+. Depletion of the stores with thapsigargin, cyclopiazonic acid, ryanodine and caffeine, high levels of the Ca2+-mobilizing hormone cholecystokinin octapeptide, or simple removal of external Ca2+ resulted in a sustained increase in Ca2+ entry on subsequent reapplication of Ca2+. This entry was attenuated by 2-aminoethoxydiphenylborane, L-type Ca2+ channel blockade, pinacidil, and Gd3+. Accumulation of the voltage-sensitive dye 3,3′-dipentylcarbocyanine and direct intracellular recordings showed that depletion of the stores is sufficient for depolarization of the plasma membrane. Contractility studies in intact gallbladder muscle strips showed that CCE induced contractions. The CCE-evoked contraction was sensitive to 2-aminoethoxydiphenylborane, L-type Ca2+ channel blockers, and Gd3+. We conclude that, in GBSM, release of Ca2+ from internal stores activates a CCE pathway and depolarizes plasma membrane, allowing coactivation of voltage-operated L-type Ca2+ channels. This process may play a role in excitation-contraction coupling in GBSM.

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