Store-Operated Calcium Channels

2005 ◽  
Vol 85 (2) ◽  
pp. 757-810 ◽  
Author(s):  
Anant B. Parekh ◽  
James W. Putney
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Excitable Cells ◽  
Entry Pathway ◽  
Crac Channels ◽  
Proliferation And Apoptosis ◽  
Intracellular Ca ◽  
Crac Channel ◽  
Cell Growth And Proliferation ◽  
Insight Into

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.

scholarly journals Regulation of Store-Operated Ca2+ Entry by SARAF

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1887
Author(s):  
Inbal Dagan ◽  
Raz Palty
Keyword(s):  
Molecular Mechanisms ◽  
Feedback Mechanism ◽  
Cellular Biology ◽  
Excitable Cells ◽  
Major Pathway ◽  
Negative Feedback Mechanism ◽  
Crac Channels ◽  
Dependent Inactivation ◽  
Crac Channel ◽  
The One

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.

Enhanced exocytotic-like insertion of Orai1 into the plasma membrane upon intracellular Ca2+ store depletion

2008 ◽  
Vol 294 (6) ◽  
pp. C1323-C1331 ◽  
Author(s):  
Geoffrey E. Woodard ◽  
Ginés M. Salido ◽  
Juan A. Rosado
Keyword(s):  
Plasma Membrane ◽  
Botulinum Neurotoxin ◽  
Surface Expression ◽  
Membrane Expression ◽  
Botulinum Neurotoxin A ◽  
Crac Channels ◽  
Store Depletion ◽  
Protein Receptor ◽  
Intracellular Ca ◽  
Crac Channel

Ca+ release-activated Ca2+ (CRAC) channels are activated when free Ca2+ concentration in the intracellular stores is substantially reduced and mediate sustained Ca2+ entry. Recent studies have identified Orai1 as a CRAC channel subunit. Here we demonstrate that passive Ca2+ store depletion using the inhibitor of the sarcoendoplasmic reticulum Ca2+-ATPase, thapsigargin (TG), enhances the surface expression of Orai1, a process that depends on rises in cytosolic free Ca2+ concentration, as demonstrated in cells loaded with dimethyl BAPTA, an intracellular Ca2+ chelator that prevented TG-evoked cytosolic free Ca2+ concentration elevation. Similar results were observed with a low concentration of carbachol. Cleavage of the soluble N-ethylmaleimide-sensitive-factor attachment protein receptor, synaptosomal-assiciated protein-25 (SNAP-25), with botulinum neurotoxin A impaired TG-induced increase in the surface expression of Orai1. In addition, SNAP-25 cleaving by botulinum neurotoxin A reduces the maintenance but not the initial stages of store-operated Ca2+ entry. In aggregate, these findings demonstrate that store depletion enhances Orai1 plasma membrane expression in an exocytotic manner that involves SNAP-25, a process that contributes to store-dependent Ca2+ entry.

scholarly journals Molecular mechanisms of STIM/Orai communication

2016 ◽  
Vol 310 (8) ◽  
pp. C643-C662 ◽  
Author(s):  
Isabella Derler ◽  
Isaac Jardin ◽  
Christoph Romanin
Keyword(s):  
Molecular Mechanisms ◽  
Signaling Cascades ◽  
Signaling Cascade ◽  
Cellular Processes ◽  
Crac Channels ◽  
Key Players ◽  
Intracellular Ca ◽  
Crac Channel ◽  
Structural Insights ◽  
Molecular Picture

Ca2+entry into the cell via store-operated Ca2+release-activated Ca2+(CRAC) channels triggers diverse signaling cascades that affect cellular processes like cell growth, gene regulation, secretion, and cell death. These store-operated Ca2+channels open after depletion of intracellular Ca2+stores, and their main features are fully reconstituted by the two molecular key players: the stromal interaction molecule (STIM) and Orai. STIM represents an endoplasmic reticulum-located Ca2+sensor, while Orai forms a highly Ca2+-selective ion channel in the plasma membrane. Functional as well as mutagenesis studies together with structural insights about STIM and Orai proteins provide a molecular picture of the interplay of these two key players in the CRAC signaling cascade. This review focuses on the main experimental advances in the understanding of the STIM1-Orai choreography, thereby establishing a portrait of key mechanistic steps in the CRAC channel signaling cascade. The focus is on the activation of the STIM proteins, the subsequent coupling of STIM1 to Orai1, and the consequent structural rearrangements that gate the Orai channels into the open state to allow Ca2+permeation into the cell.

scholarly journals Silencing of Plasma Membrane Ca2+-ATPase Isoforms 2 and 3 Impairs Energy Metabolism in Differentiating PC12 Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Tomasz Boczek ◽  
Malwina Lisek ◽  
Bozena Ferenc ◽  
Antoni Kowalski ◽  
Magdalena Wiktorska ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Pc12 Cells ◽  
Molecular Mechanisms ◽  
Atp Synthesis ◽  
Mitochondrial Activity ◽  
Excitable Cells ◽  
Close Link ◽  
Atp Level ◽  
Atp Generation

A close link between Ca2+, ATP level, and neurogenesis is apparent; however, the molecular mechanisms of this relationship have not been completely elucidated. Transient elevations of cytosolic Ca2+may boost ATP synthesis, but ATP is also consumed by ion pumps to maintain a low Ca2+in cytosol. In differentiation process plasma membrane Ca2+ATPase (PMCA) is considered as one of the major players for Ca2+homeostasis. From four PMCA isoforms, the fastest PMCA2 and PMCA3 are expressed predominantly in excitable cells. In the present study we assessed whether PMCA isoform composition may affect energy balance in differentiating PC12 cells. We found that PMCA2-downregulated cells showed higher basal O2consumption, lower NAD(P)H level, and increased activity of ETC. These changes associated with higher[Ca2+]cresulted in elevated ATP level. Since PMCA2-reduced cells demonstrated greatest sensitivity to ETC inhibition, we suppose that the main source of energy for PMCA isoforms 1, 3, and 4 was oxidative phosphorylation. Contrary, cells with unchanged PMCA2 expression exhibited prevalence of glycolysis in ATP generation. Our results with PMCA2- or PMCA3-downregulated lines provide an evidence of a novel role of PMCA isoforms in regulation of bioenergetic pathways, and mitochondrial activity and maintenance of ATP level during PC12 cells differentiation.

Complex regulation of store-operated Ca2+ entry pathway by PKC-ε in vascular SMCs

2008 ◽  
Vol 294 (6) ◽  
pp. C1499-C1508 ◽  
Author(s):  
Tarik Smani ◽  
Tina Patel ◽  
Victoria M. Bolotina
Keyword(s):  
Plasma Membrane ◽  
Significant Inhibition ◽  
Molecular Techniques ◽  
Aortic Smooth Muscle ◽  
Entry Pathway ◽  
Vascular Smcs ◽  
Intracellular Ca ◽  
Bromoenol Lactone ◽  
Complex Regulation

The role of PKC in the regulation of store-operated Ca2+ entry (SOCE) is rather controversial. Here, we used Ca2+-imaging, biochemical, pharmacological, and molecular techniques to test if Ca2+-independent PLA2β (iPLA2β), one of the transducers of the signal from depleted stores to plasma membrane channels, may be a target for the complex regulation of SOCE by PKC and diacylglycerol (DAG) in rabbit aortic smooth muscle cells (SMCs). We found that the inhibition of PKC with chelerythrine resulted in significant inhibition of thapsigargin (TG)-induced SOCE in proliferating SMCs. Activation of PKC by the diacylglycerol analog 1-oleoyl-2-acetyl- sn-glycerol (OAG) caused a significant depletion of intracellular Ca2+ stores and triggered Ca2+ influx that was similar to TG-induced SOCE. OAG and TG both produced a PKC-dependent activation of iPLA2β and Ca2+ entry that were absent in SMCs in which iPLA2β was inhibited by a specific chiral enantiomer of bromoenol lactone ( S-BEL). Moreover, we found that PKC regulates TG- and OAG-induced Ca2+ entry only in proliferating SMCs, which correlates with the expression of the specific PKC-ε isoform. Molecular downregulation of PKC-ε impaired TG- and OAG-induced Ca2+ influx in proliferating SMCs but had no effect in confluent SMCs. Our results demonstrate that DAG (or OAG) can affect SOCE via multiple mechanisms, which may involve the depletion of Ca2+ stores as well as direct PKC-ε-dependent activation of iPLA2β, resulting in a complex regulation of SOCE in proliferating and confluent SMCs.

scholarly journals Changing calcium: CRAC channel (STIM and Orai) expression, splicing, and posttranslational modifiers

2016 ◽  
Vol 310 (9) ◽  
pp. C701-C709 ◽  
Author(s):  
Barbara A. Niemeyer
Keyword(s):  
Immune Cells ◽  
Posttranslational Modifications ◽  
Splice Variants ◽  
Effector Functions ◽  
Crac Channels ◽  
Intracellular Ca ◽  
Crac Channel ◽  
The Individual ◽  
Sensor Proteins ◽  
Temporal Spread

A wide variety of cellular function depends on the dynamics of intracellular Ca2+ signals. Especially for relatively slow and lasting processes such as gene expression, cell proliferation, and often migration, cells rely on the store-operated Ca2+ entry (SOCE) pathway, which is particularly prominent in immune cells. SOCE is initiated by the sensor proteins (STIM1, STIM2) located within the endoplasmic reticulum (ER) registering the Ca2+ concentration within the ER, and upon its depletion, cluster and trap Orai (Orai1-3) proteins located in the plasma membrane (PM) into ER-PM junctions. These regions become sites of highly selective Ca2+ entry predominantly through Orai1-assembled channels, which, among other effector functions, is necessary for triggering NFAT translocation into the nucleus. What is less clear is how the spatial and temporal spread of intracellular Ca2+ is shaped and regulated by differential expression of the individual SOCE genes and their splice variants, their heteromeric combinations and pre- and posttranslational modifications. This review focuses on principle mechanisms regulating expression, splicing, and targeting of Ca2+ release-activated Ca2+ (CRAC) channels.

Store depletion and calcium influx

1997 ◽  
Vol 77 (4) ◽  
pp. 901-930 ◽  
Author(s):  
A. B. Parekh ◽  
R. Penner
Keyword(s):  
Molecular Mechanisms ◽  
Calcium Influx ◽  
Regulatory Mechanisms ◽  
Patch Clamp Technique ◽  
Electrophysiological Properties ◽  
Entry Pathway ◽  
Store Depletion ◽  
Proliferation And Apoptosis ◽  
Ca2 Channels ◽  
Intense Research

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.

Abstract 14278: Microglial Calcium Activity During Ischemic Stroke

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Kathryn N Kearns ◽  
Lei Liu ◽  
Khadijeh A Sharifi ◽  
Kenneth A Stauderman ◽  
Min S Park ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Calcium Release ◽  
Therapeutic Benefit ◽  
Artery Occlusion ◽  
Two Photon Microscopy ◽  
Crac Channels ◽  
Intracellular Ca ◽  
Crac Channel ◽  
Cerebral Artery Occlusion

Introduction: Ischemic stroke triggers waves of propagating action potentials followed by a loss of homeostatic ion gradients, known as cortical spreading depolarizations (SD). Our data indicate that microglia respond to SD by raising intracellular Ca 2+ , triggering a release of proinflammatory cytokines that may exacerbate post-stroke morbidity. Hypothesis: Inhibiting calcium release-activated calcium (CRAC) channels may block microglial Ca2+ influx and activation to potentially provide therapeutic benefit in ischemic stroke. Methods: We generated a mouse line expressing the Ca2+ indicator GCaMP5 in cortical microglia. Using two-photon microscopy, we imaged microglia in vivo following physical stroke via middle cerebral artery occlusion (MCAo) or chemical stroke via 1M KCl solution application. Controls were compared to mice treated with lipopolysaccharide (LPS) to mimic the inflammation of ischemic stroke. To study CRAC channels as a therapeutic target, we administered CM-EX-137, a CRAC channel blocker, and compared Ca2+ activity to controls. Results: We identified periodical Ca2+ waves in cortical microglia following MCAo (Fig. 1A), or localized KCl application (Fig. 1B-E). Further, when compared to controls, LPS-exposed mice expressed significantly greater microglial Ca2+ activity during KCl-triggered SD (Fig. 1C). Additionally, administration of CM-EX-137 effectively abolished the Ca2+ signals in the microglia and propagation of SD upon application of KCl (Fig. 1E). Conclusions: Blocking the Ca2+ influx into microglia after ischemic stroke may decrease the frequency of SD and reduce microglial activation, potentially leading to smaller stroke volumes and improved clinical outcomes. Figure 1: Microglial Ca 2+ after SD. (A) Ca 2+ transients in microglia after MCAo. (B) KCl-induced Ca 2+ activity in naïve microglia. (C) KCl-induced Ca 2+ activity after LPS. (D, E) KCl-induced Ca 2+ wave after (D) vehicle or (E) CM-EX-137 administration.

scholarly journals S-acylation of Orai1 regulates store-operated Ca2+ entry

2021 ◽  
Vol 135 (5) ◽  
Author(s):  
Savannah J. West ◽  
Goutham Kodakandla ◽  
Qioachu Wang ◽  
Ritika Tewari ◽  
Michael X. Zhu ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Cell Types ◽  
Central Component ◽  
Channel Activation ◽  
Crac Channels ◽  
Store Depletion ◽  
Crac Channel ◽  
Underlying Mechanisms ◽  
Different Cell Types

ABSTRACT Store-operated Ca2+ entry is a central component of intracellular Ca2+ signaling pathways. The Ca2+ release-activated channel (CRAC) mediates store-operated Ca2+ entry in many different cell types. The CRAC channel is composed of the plasma membrane (PM)-localized Orai1 channel and endoplasmic reticulum (ER)-localized STIM1 Ca2+ sensor. Upon ER Ca2+ store depletion, Orai1 and STIM1 form complexes at ER–PM junctions, leading to the formation of activated CRAC channels. Although the importance of CRAC channels is well described, the underlying mechanisms that regulate the recruitment of Orai1 to ER–PM junctions are not fully understood. Here, we describe the rapid and transient S-acylation of Orai1. Using biochemical approaches, we show that Orai1 is rapidly S-acylated at cysteine 143 upon ER Ca2+ store depletion. Importantly, S-acylation of cysteine 143 is required for Orai1-mediated Ca2+ entry and recruitment to STIM1 puncta. We conclude that store depletion-induced S-acylation of Orai1 is necessary for recruitment to ER–PM junctions, subsequent binding to STIM1 and channel activation.

Ca2+ release-activated Ca2+ channels are responsible for histamine-induced Ca2+ entry, permeability increase, and interleukin synthesis in lymphatic endothelial cells

2020 ◽  
Vol 318 (5) ◽  
pp. H1283-H1295 ◽  
Author(s):  
Hongjiang Si ◽  
Jian Wang ◽  
Cynthia J. Meininger ◽  
Xu Peng ◽  
David C. Zawieja ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Molecular Mechanisms ◽  
Immune Surveillance ◽  
Endothelial Barrier ◽  
Channel Blockers ◽  
Lymphatic Endothelial Cells ◽  
Histamine Stimulation ◽  
Cellular Effects ◽  
Crac Channels ◽  
Crac Channel

The lymphatic functions in maintaining lymph transport, and immune surveillance can be impaired by infections and inflammation, thereby causing debilitating disorders, such as lymphedema and inflammatory bowel disease. Histamine is a key inflammatory mediator known to trigger vasodilation and vessel hyperpermeability upon binding to its receptors and evoking intracellular Ca2+ ([Ca2+]i) dynamics for downstream signal transductions. However, the exact molecular mechanisms beneath the [Ca2+]i dynamics and the downstream cellular effects have not been elucidated in the lymphatic system. Here, we show that Ca2+ release-activated Ca2+ (CRAC) channels, formed by Orai1 and stromal interaction molecule 1 (STIM1) proteins, are required for the histamine-elicited Ca2+ signaling in human dermal lymphatic endothelial cells (HDLECs). Blockers or antagonists against CRAC channels, phospholipase C, and H1R receptors can all significantly diminish the histamine-evoked [Ca2+]i dynamics in lymphatic endothelial cells (LECs), while short interfering RNA-mediated knockdown of endogenous Orai1 or STIM1 also abolished the Ca2+ entry upon histamine stimulation in LECs. Furthermore, we find that histamine compromises the lymphatic endothelial barrier function by increasing the intercellular permeability and disrupting vascular endothelial-cadherin integrity, which is remarkably attenuated by CRAC channel blockers. Additionally, the upregulated expression of inflammatory cytokines, IL-6 and IL-8, after histamine stimulation was abolished by silencing Orai1 or STIM1 with RNAi in LECs. Taken together, our data demonstrated the essential role of CRAC channels in mediating the [Ca2+]i signaling and downstream endothelial barrier and inflammatory functions induced by histamine in the LECs, suggesting a promising potential to relieve histamine-triggered vascular leakage and inflammatory disorders in the lymphatics by targeting CRAC channel functions.

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