151
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TMCO1 Is an ER Ca 2+ Load-Activated Ca 2+ Channel. Cell 2016; 165:1454-1466. [DOI: 10.1016/j.cell.2016.04.051] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 02/20/2016] [Accepted: 04/14/2016] [Indexed: 11/18/2022]
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152
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Jardin I, Rosado JA. STIM and calcium channel complexes in cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1418-26. [DOI: 10.1016/j.bbamcr.2015.10.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/25/2015] [Accepted: 10/07/2015] [Indexed: 12/12/2022]
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153
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Deb BK, Pathak T, Hasan G. Store-independent modulation of Ca(2+) entry through Orai by Septin 7. Nat Commun 2016; 7:11751. [PMID: 27225060 PMCID: PMC4894974 DOI: 10.1038/ncomms11751] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/26/2016] [Indexed: 01/07/2023] Open
Abstract
Orai channels are required for store-operated Ca2+ entry (SOCE) in multiple cell types. Septins are a class of GTP-binding proteins that function as diffusion barriers in cells. Here we show that Septin 7 acts as a ‘molecular brake’ on activation of Orai channels in Drosophila neurons. Lowering Septin 7 levels results in dOrai-mediated Ca2+ entry and higher cytosolic Ca2+ in resting neurons. This Ca2+ entry is independent of depletion of endoplasmic reticulum Ca2+ stores and Ca2+ release through the inositol-1,4,5-trisphosphate receptor. Importantly, store-independent Ca2+ entry through Orai compensates for reduced SOCE in the Drosophila flight circuit. Moreover, overexpression of Septin 7 reduces both SOCE and flight duration, supporting its role as a negative regulator of Orai channel function in vivo. Septin 7 levels in neurons can, therefore, alter neural circuit function by modulating Orai function and Ca2+ homeostasis. Orai channels are well known to mediate store-operated calcium entry. Here authors show that in neurons of the Drosophila flight circuit, Septin 7 acts as a negative regulator of Orai channels, surprisingly, by modulating store-independent calcium entry through Orai.
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Affiliation(s)
- Bipan Kumar Deb
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Trayambak Pathak
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India.,Manipal University, Manipal, Karnataka 576104, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
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154
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Lopez JJ, Albarran L, Gómez LJ, Smani T, Salido GM, Rosado JA. Molecular modulators of store-operated calcium entry. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2037-43. [PMID: 27130253 DOI: 10.1016/j.bbamcr.2016.04.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/13/2016] [Accepted: 04/25/2016] [Indexed: 12/20/2022]
Abstract
Three decades ago, store-operated Ca(2+) entry (SOCE) was identified as a unique mechanism for Ca(2+) entry through plasma membrane (PM) Ca(2+)-permeable channels modulated by the intracellular Ca(2+) stores, mainly the endoplasmic reticulum (ER). Extensive analysis of the communication between the ER and the PM leads to the identification of the protein STIM1 as the ER-Ca(2+) sensor that gates the Ca(2+) channels in the PM. Further analysis on the biophysical, electrophysiological and biochemical properties of STIM1-dependent Ca(2+) channels has revealed the presence of a highly Ca(2+)-selective channel termed Ca(2+) release-activated Ca(2+) channel (CRAC), consisting of Orai1 subunits, and non-selective cation channels named store-operated channels (SOC), including both Orai1 and TRPC channel subunits. Since the identification of the key elements of CRAC and SOC channels a number of intracellular modulators have been reported to play essential roles in the stabilization of STIM-Orai interactions, collaboration with STIM1 conformational changes or mediating slow Ca(2+)-dependent inactivation. Here, we review our current understanding of some of the key modulators of STIM1-Orai1 interaction, including the proteins CRACR2A, STIMATE, SARAF, septins, golli and ORMDL3.
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Affiliation(s)
- Jose J Lopez
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Letizia Albarran
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Luis J Gómez
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Sevilla, Sevilla, Spain
| | - Gines M Salido
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain.
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155
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Albarran L, Lopez JJ, Amor NB, Martin-Cano FE, Berna-Erro A, Smani T, Salido GM, Rosado JA. Dynamic interaction of SARAF with STIM1 and Orai1 to modulate store-operated calcium entry. Sci Rep 2016; 6:24452. [PMID: 27068144 PMCID: PMC4828706 DOI: 10.1038/srep24452] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 03/30/2016] [Indexed: 12/16/2022] Open
Abstract
Ca(2+) influx by store-operated Ca(2+) channels is a major mechanism for intracellular Ca(2+) homeostasis and cellular function. Here we present evidence for the dynamic interaction between the SOCE-associated regulatory factor (SARAF), STIM1 and Orai1. SARAF overexpression attenuated SOCE and the STIM1-Orai1 interaction in cells endogenously expressing STIM1 and Orai1 while RNAi-mediated SARAF silencing induced opposite effects. SARAF impaired the association between Orai1 and the Orai1-activating small fragment of STIM1 co-expressed in the STIM1-deficient NG115-401L cells. Cell treatment with thapsigargin or physiological agonists results in direct association of SARAF with Orai1. STIM1-independent interaction of SARAF with Orai1 leads to activation of this channel. In cells endogenously expressing STIM1 and Orai1, Ca(2+) store depletion leads to dissociation of SARAF with STIM1 approximately 30s after treatment with thapsigargin, which paralleled the increase in SARAF-Orai1 interaction, followed by reinteraction with STIM1 and dissociation from Orai1. Co-expression of SARAF and either Orai1 or various N-terminal deletion Orai1 mutants did not alter SARAF-Orai1 interaction; however, expression of C-terminal deletion Orai1 mutants or blockade of the C-terminus of Orai1 impair the interaction with SARAF. These observations suggest that SARAF exerts an initial positive role in the activation of SOCE followed by the facilitation of SCDI of Orai1.
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Affiliation(s)
- Letizia Albarran
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Jose J Lopez
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Nidhal Ben Amor
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Francisco E Martin-Cano
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Alejandro Berna-Erro
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, Institute of Biomedicine of Sevilla, Sevilla, Spain
| | - Gines M Salido
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology (Cellular Physiology and Muscle Physiology Research Groups), University of Extremadura, 10003 Cáceres, Spain
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156
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Srivats S, Balasuriya D, Pasche M, Vistal G, Edwardson JM, Taylor CW, Murrell-Lagnado RD. Sigma1 receptors inhibit store-operated Ca2+ entry by attenuating coupling of STIM1 to Orai1. J Cell Biol 2016; 213:65-79. [PMID: 27069021 PMCID: PMC4828687 DOI: 10.1083/jcb.201506022] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 02/24/2016] [Indexed: 11/24/2022] Open
Abstract
Sigma1 receptors (σ1Rs) are expressed widely; they bind diverse ligands, including psychotropic drugs and steroids, regulate many ion channels, and are implicated in cancer and addiction. It is not known how σ1Rs exert such varied effects. We demonstrate that σ1Rs inhibit store-operated Ca(2+)entry (SOCE), a major Ca(2+)influx pathway, and reduce the Ca(2+)content of the intracellular stores. SOCE was inhibited by expression of σ1R or an agonist of σ1R and enhanced by loss of σ1R or an antagonist. Within the endoplasmic reticulum (ER), σ1R associated with STIM1, the ER Ca(2+)sensor that regulates SOCE. This interaction was modulated by σ1R ligands. After depletion of Ca(2+)stores, σ1R accompanied STIM1 to ER-plasma membrane (PM) junctions where STIM1 stimulated opening of the Ca(2+)channel, Orai1. The association of STIM1 with σ1R slowed the recruitment of STIM1 to ER-PM junctions and reduced binding of STIM1 to PM Orai1. We conclude that σ1R attenuates STIM1 coupling to Orai1 and thereby inhibits SOCE.
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Affiliation(s)
- Shyam Srivats
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Dilshan Balasuriya
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Mathias Pasche
- MRC Laboratory for Molecular Biology, Cambridge CB2 0QH, England, UK
| | - Gerard Vistal
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - J Michael Edwardson
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK
| | - Ruth D Murrell-Lagnado
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, England, UK Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, England, UK
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157
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Chang CL, Liou J. Homeostatic regulation of the PI(4,5)P2-Ca(2+) signaling system at ER-PM junctions. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:862-873. [PMID: 26924250 DOI: 10.1016/j.bbalip.2016.02.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 10/22/2022]
Abstract
The phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2)-Ca(2+) signaling system is important for cell activation in response to various extracellular stimuli. This signaling system is initiated by receptor-induced hydrolysis of PI(4,5)P2 in the plasma membrane (PM) to generate the soluble second messenger inositol 1,4,5-trisphosphate (IP3). IP3 subsequently triggers the release of Ca(2+) from the endoplasmic reticulum (ER) store to the cytosol to activate Ca(2+)-mediated responses, such as secretion and proliferation. The consumed PM PI(4,5)P2 and ER Ca(2+) must be quickly restored to sustain signaling responses, and to maintain the homeostasis of PI(4,5)P2 and Ca(2+). Since phosphatidylinositol (PI), the precursor lipid for PM PI(4,5)P2, is synthesized in the ER membrane, and a Ca(2+) influx across the PM is required to refill the ER Ca(2+) store, efficient communications between the ER and the PM are critical for the homeostatic regulation of the PI(4,5)P2-Ca(2+) signaling system. This review describes the major findings that established the framework of the PI(4,5)P2-Ca(2+) signaling system, and recent discoveries on feedback control mechanisms at ER-PM junctions that sustain the PI(4,5)P2-Ca(2+) signaling system. Particular emphasis is placed on the characterization of ER-PM junctions where efficient communications between the ER and the PM occur, and the activation mechanisms of proteins that dynamically localize to ER-PM junctions to provide the feedback control during PI(4,5)P2-Ca(2+) signaling, including the ER Ca(2+) sensor STIM1, the extended synaptotagmin E-Syt1, and the PI transfer protein Nir2. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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Affiliation(s)
- Chi-Lun Chang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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158
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Abstract
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.
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Affiliation(s)
- Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
| | - Isaac Jardin
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
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159
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Albarran L, Lopez JJ, Woodard GE, Salido GM, Rosado JA. Store-operated Ca2+ Entry-associated Regulatory factor (SARAF) Plays an Important Role in the Regulation of Arachidonate-regulated Ca2+ (ARC) Channels. J Biol Chem 2016; 291:6982-8. [PMID: 26817842 DOI: 10.1074/jbc.m115.704940] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 01/15/2023] Open
Abstract
The store-operated Ca(2+)entry-associated regulatory factor (SARAF) has recently been identified as a STIM1 regulatory protein that facilitates slow Ca(2+)-dependent inactivation of store-operated Ca(2+)entry (SOCE). Both the store-operated channels and the store-independent arachidonate-regulated Ca(2+)(ARC) channels are regulated by STIM1. In the present study, we show that, in addition to its location in the endoplasmic reticulum, SARAF is constitutively expressed in the plasma membrane, where it can interact with plasma membrane (PM)-resident ARC forming subunits in the neuroblastoma cell line SH-SY5Y. Using siRNA-based and overexpression approaches we report that SARAF negatively regulates store-independent Ca(2+)entry via the ARC channels. Arachidonic acid (AA) increases the association of PM-resident SARAF with Orai1. Finally, our results indicate that SARAF modulates the ability of AA to promote cell survival in neuroblastoma cells. In addition to revealing new insight into the biology of ARC channels in neuroblastoma cells, these findings provide evidence for an unprecedented location of SARAF in the plasma membrane.
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Affiliation(s)
- Letizia Albarran
- From the Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10003 Caceres, Spain and
| | - Jose J Lopez
- From the Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10003 Caceres, Spain and
| | - Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Gines M Salido
- From the Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10003 Caceres, Spain and
| | - Juan A Rosado
- From the Department of Physiology (Cellular Physiology Research Group), University of Extremadura, 10003 Caceres, Spain and
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160
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Derler I, Jardin I, Stathopulos PB, Muik M, Fahrner M, Zayats V, Pandey SK, Poteser M, Lackner B, Absolonova M, Schindl R, Groschner K, Ettrich R, Ikura M, Romanin C. Cholesterol modulates Orai1 channel function. Sci Signal 2016; 9:ra10. [PMID: 26814231 DOI: 10.1126/scisignal.aad7808] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
STIM1 (stromal interaction molecule 1) and Orai proteins are the essential components of Ca(2+) release-activated Ca(2+) (CRAC) channels. We focused on the role of cholesterol in the regulation of STIM1-mediated Orai1 currents. Chemically induced cholesterol depletion enhanced store-operated Ca(2+) entry (SOCE) and Orai1 currents. Furthermore, cholesterol depletion in mucosal-type mast cells augmented endogenous CRAC currents, which were associated with increased degranulation, a process that requires calcium influx. Single point mutations in the Orai1 amino terminus that would be expected to abolish cholesterol binding enhanced SOCE to a similar extent as did cholesterol depletion. The increase in Orai1 activity in cells expressing these cholesterol-binding-deficient mutants occurred without affecting the amount in the plasma membrane or the coupling of STIM1 to Orai1. We detected cholesterol binding to an Orai1 amino-terminal fragment in vitro and to full-length Orai1 in cells. Thus, our data showed that Orai1 senses the amount of cholesterol in the plasma membrane and that the interaction of Orai1 with cholesterol inhibits its activity, thereby limiting SOCE.
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Affiliation(s)
- Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria.
| | - Isaac Jardin
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Martin Muik
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Marc Fahrner
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Vasilina Zayats
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, CZ-373 33 Nové Hrady, Czech Republic
| | - Saurabh K Pandey
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, CZ-373 33 Nové Hrady, Czech Republic
| | - Michael Poteser
- Institute of Biophysics, Medical University of Graz, Harrachgasse 21/4, 8010 Graz, Austria
| | - Barbara Lackner
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Marketa Absolonova
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Rainer Schindl
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Klaus Groschner
- Institute of Biophysics, Medical University of Graz, Harrachgasse 21/4, 8010 Graz, Austria
| | - Rüdiger Ettrich
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, CZ-373 33 Nové Hrady, Czech Republic
| | - Mitsu Ikura
- Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020 Linz, Austria.
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161
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den Hartogh SC, Wolstencroft K, Mummery CL, Passier R. A comprehensive gene expression analysis at sequential stages of in vitro cardiac differentiation from isolated MESP1-expressing-mesoderm progenitors. Sci Rep 2016; 6:19386. [PMID: 26783251 PMCID: PMC4726039 DOI: 10.1038/srep19386] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/02/2015] [Indexed: 01/03/2023] Open
Abstract
In vitro cardiac differentiation of human pluripotent stem cells (hPSCs) closely recapitulates in vivo embryonic heart development, and therefore, provides an excellent model to study human cardiac development. We recently generated the dual cardiac fluorescent reporter MESP1mCherry/wNKX2-5eGFP/w line in human embryonic stem cells (hESCs), allowing the visualization of pre-cardiac MESP1+ mesoderm and their further commitment towards the cardiac lineage, marked by activation of the cardiac transcription factor NKX2-5. Here, we performed a comprehensive whole genome based transcriptome analysis of MESP1-mCherry derived cardiac-committed cells. In addition to previously described cardiac-inducing signalling pathways, we identified novel transcriptional and signalling networks indicated by transient activation and interactive network analysis. Furthermore, we found a highly dynamic regulation of extracellular matrix components, suggesting the importance to create a versatile niche, adjusting to various stages of cardiac differentiation. Finally, we identified cell surface markers for cardiac progenitors, such as the Leucine-rich repeat-containing G-protein coupled receptor 4 (LGR4), belonging to the same subfamily of LGR5, and LGR6, established tissue/cancer stem cells markers. We provide a comprehensive gene expression analysis of cardiac derivatives from pre-cardiac MESP1-progenitors that will contribute to a better understanding of the key regulators, pathways and markers involved in human cardiac differentiation and development.
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Affiliation(s)
- Sabine C den Hartogh
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Katherine Wolstencroft
- Leiden Institute of Advanced Computer Science Leiden Institute of Advanced Computer Science, Leiden University, The Netherlands
| | - Christine L Mummery
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Robert Passier
- Department of Anatomy and Embryology, Leiden University Medical Centre, Leiden, The Netherlands.,Department of Applied Stem cell Technologies. MIRA Institute for Biomedical Technology and Technical Medicine. University of Twente, P.O.Box 217, Enschede, The Netherlands
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162
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Son A, Park S, Shin DM, Muallem S. Orai1 and STIM1 in ER/PM junctions: roles in pancreatic cell function and dysfunction. Am J Physiol Cell Physiol 2016; 310:C414-22. [PMID: 26739495 DOI: 10.1152/ajpcell.00349.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane contact sites (MCS) are critical junctions that form between the endoplasmic reticulum (ER) and membranes of various organelles, including the plasma membrane (PM). Signaling complexes, including mediators of Ca(2+) signaling, are assembled within MCS, such as the ER/PM junction. This is most evident in polarized epithelial cells, such as pancreatic cells. Core Ca(2+) signaling proteins cluster at the apical pole, the site of inositol 1,4,5-trisphosphate-mediated Ca(2+) release and Orai1/transient receptor potential canonical-mediated store-dependent Ca(2+) entry. Recent advances have characterized the proteins that tether the membranes at MCS and the role of these proteins in modulating physiological and pathological intracellular signaling. This review discusses recent advances in the characterization of Ca(2+) signaling at ER/PM junctions and the relation of these junctions to physiological and pathological Ca(2+) signaling in pancreatic acini.
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Affiliation(s)
- Aran Son
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Seonghee Park
- Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
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163
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Shin DM, Son A, Park S, Kim MS, Ahuja M, Muallem S. The TRPCs, Orais and STIMs in ER/PM Junctions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:47-66. [PMID: 27161224 DOI: 10.1007/978-3-319-26974-0_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Ca(2+) second messenger is initiated at ER/PM junctions and propagates into the cell interior to convey the receptor information. The signal is maintained by Ca(2+) influx across the plasma membrane through the Orai and TRPC channels. These Ca(2+) influx channels form complexes at ER/PM junctions with the ER Ca(2+) sensor STIM1, which activates the channels. The function of STIM1 is modulated by other STIM isoforms like STIM1L, STIM2 and STIM2.1/STIM2β and by SARAF, which mediates the Ca(2+)-dependent inhibition of Orai channels. The ER/PM junctions are formed at membrane contact sites by tethering proteins that generate several types of ER/PM junctions, such as PI(4,5)P2-poor and PI(4,5)P2-rich domains. This chapter discusses several properties of the TRPC channels, the Orai channels and the STIMs, their key interacting proteins and how interaction of the STIMs with the channels gates their activity. The chapter closes by highlighting open questions and potential future directions in this field.
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Affiliation(s)
- Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, 120-752, South Korea.
| | - Aran Son
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
| | - Seonghee Park
- Department of Physiology, School of Medicine, EwhaWomans University, 911-1 Mok-6-dong, Yang Chun-gu, Seoul, 158-710, South Korea
| | - Min Seuk Kim
- Department of Oral Physiology, School of Dentistry, Wonkwang University, Iksan City, Jeonbuk, South Korea
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA.
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164
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Abstract
Store Operated Ca(2+) Entry (SOCE), the main Ca(2+) influx mechanism in non-excitable cells, is implicated in the immune response and has been reported to be affected in several pathologies including cancer. The basic molecular constituents of SOCE are Orai, the pore forming unit, and STIM, a multidomain protein with at least two principal functions: one is to sense the Ca(2+) content inside the lumen of the endoplasmic reticulum(ER) and the second is to activate Orai channels upon depletion of the ER. The link between Ca(2+) depletion inside the ER and Ca(2+) influx from extracellular media is through a direct association of STIM and Orai, but for this to occur, both molecules have to interact and form clusters where ER and plasma membrane (PM) are intimately apposed. In recent years a great number of components have been identified as participants in SOCE regulation, including regions of plasma membrane enriched in cholesterol and sphingolipids, the so called lipid rafts, which recruit a complex platform of specialized microdomains, which cells use to regulate spatiotemporal Ca(2+) signals.
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165
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Hoth M. CRAC channels, calcium, and cancer in light of the driver and passenger concept. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1408-17. [PMID: 26705695 DOI: 10.1016/j.bbamcr.2015.12.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/09/2015] [Accepted: 12/15/2015] [Indexed: 01/18/2023]
Abstract
Advances in next-generation sequencing allow very comprehensive analyses of large numbers of cancer genomes leading to an increasingly better characterization and classification of cancers. Comparing genomic data predicts candidate genes driving development, growth, or metastasis of cancer. Cancer driver genes are defined as genes whose mutations are causally implicated in oncogenesis whereas passenger mutations are defined as not being oncogenic. Currently, a list of several hundred cancer driver mutations is discussed including prominent members like TP53, BRAF, NRAS, or NF1. According to the vast literature on Ca(2+) and cancer, Ca(2+) signals and the underlying Ca(2+) channels and transporters certainly influence the development, growth, and metastasis of many cancers. In this review, I focus on the calcium release-activated calcium (CRAC) channel genes STIM and Orai and their role for cancer development, growth, and metastasis. STIM and Orai genes are being discussed in the context of current cancer concepts with a focus on the driver-passenger hypothesis. One result of this discussion is the hypothesis that a driver analysis of Ca(2+) homeostasis-related genes should not be carried out by looking at isolated genes. Rather a pool of “Ca(2+) genes” might be considered to act as one potential cancer driver. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.
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Affiliation(s)
- Markus Hoth
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Building 48, Saarland University, D-66421 Homburg, Germany.
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166
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Palty R, Isacoff EY. Cooperative Binding of Stromal Interaction Molecule 1 (STIM1) to the N and C Termini of Calcium Release-activated Calcium Modulator 1 (Orai1). J Biol Chem 2015; 291:334-41. [PMID: 26546674 DOI: 10.1074/jbc.m115.685289] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Indexed: 11/06/2022] Open
Abstract
Calcium flux through store-operated calcium entry is a central regulator of intracellular calcium signaling. The two key components of the store-operated calcium release-activated calcium channel are the Ca(2+)-sensing protein stromal interaction molecule 1 (STIM1) and the channel pore-forming protein Orai1. During store-operated calcium entry activation, calcium depletion from the endoplasmic reticulum triggers a series of conformational changes in STIM1 that unmask a minimal Orai1-activating domain (CRAC activation region (CAD)). To gate Orai1 channels, the exposed STIM1-activating domain binds to two sites in Orai1, one in the N terminus and one in the C terminus. Whether the two sites operate as distinct binding domains or cooperate in CAD binding is unknown. In this study, we show that the N and C-terminal domains of Orai1 synergistically contribute to the interaction with STIM1 and couple STIM1 binding with channel gating and modulation of ion selectivity.
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Affiliation(s)
- Raz Palty
- From the Department of Molecular and Cell Biology and
| | - Ehud Y Isacoff
- From the Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California 94720 and the Physical Bioscience Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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167
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Segal M, Korkotian E. Roles of Calcium Stores and Store-Operated Channels in Plasticity of Dendritic Spines. Neuroscientist 2015; 22:477-85. [PMID: 26511041 DOI: 10.1177/1073858415613277] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calcium stores in the endoplasmic reticulum play important roles in a variety of mammalian cellular functions. However, the multitude of calcium-handling machineries in neurons, including voltage- and ligand-gated channels, calcium-binding proteins, pumps, and transporters, as well as the rapid mobility of calcium ions among different cellular compartments hampered the singling out of calcium stores as a pivotal player in synaptic plasticity. Despite these methodological obstacles, novel molecular and imaging tools afforded a rapid progress in deciphering the role of specific calcium stores in neuronal functions. In the present review, we will address several key issues related to the involvement of ryanodine receptors and the calcium entry channel Orai1 in dendritic spine development and plasticity as well as their derailing in neurodegenerative diseases.
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Affiliation(s)
- Menahem Segal
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
| | - Eduard Korkotian
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
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168
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Ong HL, Ambudkar IS. Molecular determinants of TRPC1 regulation within ER–PM junctions. Cell Calcium 2015; 58:376-86. [DOI: 10.1016/j.ceca.2015.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 11/30/2022]
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169
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Abstract
Decreases in endoplasmic reticulum calcium content are sensed by resident STIM proteins, which can activate plasma membrane Orai channels to facilitate Ca(2+) entry. The role of STIMATE, a previously unknown component of the store-operated calcium entry complex, has now been identified and defined.
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Affiliation(s)
- Robert Hooper
- Fels Institute for Cancer Research and Molecular Biology,
Temple University School of Medicine, Philadelphia, PA, 19140, USA
| | - Jonathan Soboloff
- Fels Institute for Cancer Research and Molecular Biology,
Temple University School of Medicine, Philadelphia, PA, 19140, USA
- Department of Medical Genetics & Molecular
Biochemistry, Temple University School of Medicine, Philadelphia, PA, 19140,
USA
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170
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Abstract
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 Ca(2+) 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 Ca(2+) 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 Ca(2+) 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 Ca(2+) 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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Affiliation(s)
- Murali Prakriya
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
| | - Richard S Lewis
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
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171
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Cao X, Choi S, Maléth JJ, Park S, Ahuja M, Muallem S. The ER/PM microdomain, PI(4,5)P₂ and the regulation of STIM1-Orai1 channel function. Cell Calcium 2015; 58:342-8. [PMID: 25843208 PMCID: PMC4564333 DOI: 10.1016/j.ceca.2015.03.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 12/18/2022]
Abstract
All forms of cell signaling occur in discreet cellular microdomains in which the ER is the main participant and include microdomains formed by the ER with lysosomes, endosomes, the nucleus, mitochondria and the plasma membrane. In the microdomains the two opposing organelles transfer and exchange constituents including lipids and ions. As is the case for other forms of signaling pathways, many components of the receptor-evoked Ca(2+) signal are clustered at the ER/PM microdomain, including the Orai1-STIM1 complex. This review discusses recent advances in understanding the molecular components that tether the ER and plasma membrane to form the ER/PM microdomains in which PI(4,5)P2 is enriched, and how dynamic targeting of the Orai1-STIM1 complex to PI(4,5)P2-poor and PI(4,5)P2-rich microdomains controls the activity of Orai1 and its regulation by Ca(2+) that is mediated by SARAF.
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Affiliation(s)
- Xu Cao
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, United States
| | - Seok Choi
- Department of Physiology, College of Medicine, Chosun University, 501-375, Republic of Korea
| | - Jozsef J Maléth
- First Department of Medicine, University of Szeged, Szeged H-6725, Hungary
| | - Seonghee Park
- Department of Physiology, School of Medicine, Ewha Womans University, 911-1 Mok-6-dong, Yang Chun-gu, Seoul 158-710, Republic of Korea
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, United States
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, United States.
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172
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Store-operated calcium entry: Mechanisms and modulation. Biochem Biophys Res Commun 2015; 460:40-9. [PMID: 25998732 DOI: 10.1016/j.bbrc.2015.02.110] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/20/2015] [Indexed: 11/22/2022]
Abstract
Store-operated calcium entry is a central mechanism in cellular calcium signalling and in maintaining cellular calcium balance. This review traces the history of research on store-operated calcium entry, the discovery of STIM and ORAI as central players in calcium entry, and the role of STIM and ORAI in biology and human disease. It describes current knowledge of the basic mechanism of STIM-ORAI signalling and of the varied mechanisms by which STIM-ORAI signalling can be modulated.
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173
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Ca(2+) homeostasis and endoplasmic reticulum (ER) stress: An integrated view of calcium signaling. Biochem Biophys Res Commun 2015; 460:114-21. [PMID: 25998740 DOI: 10.1016/j.bbrc.2015.02.004] [Citation(s) in RCA: 378] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 02/02/2015] [Indexed: 12/21/2022]
Abstract
Cellular Ca(2+) homeostasis is maintained through the integrated and coordinated function of Ca(2+) transport molecules, Ca(2+) buffers and sensors. These molecules are associated with the plasma membrane and different cellular compartments, such as the cytoplasm, nucleus, mitochondria, and cellular reticular network, including the endoplasmic reticulum (ER) to control free and bound Ca(2+) levels in all parts of the cell. Loss of nutrients/energy leads to the loss of cellular homeostasis and disruption of Ca(2+) signaling in both the reticular network and cytoplasmic compartments. As an integral part of cellular physiology and pathology, this leads to activation of ER stress coping responses, such as the unfolded protein response (UPR), and mobilization of pathways to regain ER homeostasis.
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174
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Critical role for Orai1 C-terminal domain and TM4 in CRAC channel gating. Cell Res 2015; 25:963-80. [PMID: 26138675 DOI: 10.1038/cr.2015.80] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/30/2015] [Accepted: 05/22/2015] [Indexed: 01/12/2023] Open
Abstract
Calcium flux through store-operated calcium entry is a major regulator of intracellular calcium homeostasis and various calcium signaling pathways. Two key components of the store-operated calcium release-activated calcium channel are the Ca(2+)-sensing protein stromal interaction molecule 1 (STIM1) and the channel pore-forming protein Orai1. Following calcium depletion from the endoplasmic reticulum, STIM1 undergoes conformational changes that unmask an Orai1-activating domain called CAD. CAD binds to two sites in Orai1, one in the N terminal and one in the C terminal. Most previous studies suggested that gating is initiated by STIM1 binding at the Orai1 N-terminal site, just proximal to the TM1 pore-lining segment, and that binding at the C terminal simply anchors STIM1 within reach of the N terminal. However, a recent study had challenged this view and suggested that the Orai1 C-terminal region is more than a simple STIM1-anchoring site. In this study, we establish that the Orai1 C-terminal domain plays a direct role in gating. We identify a linker region between TM4 and the C-terminal STIM1-binding segment of Orai1 as a key determinant that couples STIM1 binding to gating. We further find that Proline 245 in TM4 of Orai1 is essential for stabilizing the closed state of the channel. Taken together with previous studies, our results suggest a dual-trigger mechanism of Orai1 activation in which binding of STIM1 at the N- and C-terminal domains of Orai1 induces rearrangements in proximal membrane segments to open the channel.
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175
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Rana A, Yen M, Sadaghiani AM, Malmersjö S, Park CY, Dolmetsch RE, Lewis RS. Alternative splicing converts STIM2 from an activator to an inhibitor of store-operated calcium channels. J Cell Biol 2015; 209:653-69. [PMID: 26033257 PMCID: PMC4460148 DOI: 10.1083/jcb.201412060] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 04/27/2015] [Indexed: 11/22/2022] Open
Abstract
STIM2β is a novel STIM2 splice isoform that inhibits Orai channels. Store-operated calcium entry (SOCE) regulates a wide variety of essential cellular functions. SOCE is mediated by STIM1 and STIM2, which sense depletion of ER Ca2+ stores and activate Orai channels in the plasma membrane. Although the amplitude and dynamics of SOCE are considered important determinants of Ca2+-dependent responses, the underlying modulatory mechanisms are unclear. In this paper, we identify STIM2β, a highly conserved alternatively spliced isoform of STIM2, which, in contrast to all known STIM isoforms, is a potent inhibitor of SOCE. Although STIM2β does not by itself strongly bind Orai1, it is recruited to Orai1 channels by forming heterodimers with other STIM isoforms. Analysis of STIM2β mutants and Orai1-STIM2β chimeras suggested that it actively inhibits SOCE through a sequence-specific allosteric interaction with Orai1. Our results reveal a previously unrecognized functional flexibility in the STIM protein family by which alternative splicing creates negative and positive regulators of SOCE to shape the amplitude and dynamics of Ca2+ signals.
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Affiliation(s)
- Anshul Rana
- Graduate Program in Biochemistry, Stanford University School of Medicine, Stanford, CA 94305 Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Michelle Yen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305 Graduate Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Amir Masoud Sadaghiani
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305 Novartis Institutes for Biomedical Research, Boston, MA 02139
| | - Seth Malmersjö
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Chan Young Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 689-798, South Korea
| | - Ricardo E Dolmetsch
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305 Novartis Institutes for Biomedical Research, Boston, MA 02139
| | - Richard S Lewis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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176
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Potentiation of the store-operated calcium entry (SOCE) induces phytohemagglutinin-activated Jurkat T cell apoptosis. Cell Calcium 2015; 58:171-85. [PMID: 25963393 DOI: 10.1016/j.ceca.2015.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 01/12/2023]
Abstract
Store-operated Ca(2+) entry (SOCE) is the main Ca(2+) entry pathway of non-excitable cells. In the past decade, the activation of this entry has been unveiled, with STIM1, a protein of the endoplasmic reticulum able to sense the intraluminal Ca(2+) content, and Orai1, the pore-forming unit of the Ca(2+) release activated Ca(2+) (CRAC) channels. When Ca(2+) ions are released from the endoplasmic reticulum, STIM1 proteins oligomerize and directly interact with Orai1 proteins, allowing the opening of the CRAC channels and a massive Ca(2+) ion influx known as SOCE. As Ca(2+) is involved in various cellular processes, the discovery of new drugs acting on the SOCE should be of interest to control the cell activity. By testing analogs of 2-aminoethyl diphenylborinate (2-APB), a well known, though not so selective effector of the SOCE, we identified methoxy diethylborinate (MDEB), a molecule able to potentiate the SOCE in three leukocyte and two breast cancer cell lines by increasing the Ca(2+) influx amplitude. Unlike 2-APB, MDEB does not affect the Ca(2+) pumps or the Ca(2+) release from the endoplasmic reticulum. MDEB could therefore represent the first member of a new group of molecules, specifically able to potentiate SOCE. Although not toxic for non-activated Jurkat T cells, it could induce the apoptosis of phytohemagglutinin-stimulated cells.
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177
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Wang LY, Zhang JH, Yu J, Yang J, Deng MY, Kang HL, Huang L. Reduction of Store-Operated Ca(2+) Entry Correlates with Endothelial Progenitor Cell Dysfunction in Atherosclerotic Mice. Stem Cells Dev 2015; 24:1582-90. [PMID: 25753987 DOI: 10.1089/scd.2014.0538] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The dysfunction of endothelial progenitor cells (EPCs) has been shown to prevent endothelial repair during the development of atherosclerosis (AS). Previous studies have revealed that store-operated calcium entry (SOCE) is an important factor in regulating EPC functions. However, whether this is also the mechanism in AS has not been elucidated. Therefore, we evaluated the role of SOCE in EPCs isolated from an atherosclerotic mouse model. Atheromatous plaques were more frequent in the aortas of ApoE(-/-) mice fed a high-fat diet for 16 weeks compared with controls, and the proliferative and migratory activities of atherosclerotic EPCs were significantly decreased. Accordingly, SOCE amplitude, as well as spontaneous or VEGF-induced Ca(2+) oscillations, decreased in atherosclerotic EPCs. These results may be associated with the downregulated expression of Stim1, Orai1, and TRPC1, which are major mediators of SOCE. In addition, eNOS expression and phosphorylation at Ser(1177), which are critical regulators of EPC function, were markedly reduced in the atherosclerotic EPCs. The impairment of eNOS activity could also be induced by using an SOCE inhibitor or by Stim1 gene silencing, indicating a link between the activities of eNOS and SOCE in AS. Furthermore, decreased SOCE function inhibited EPC proliferation and migration in vitro. In conclusion, our results showed that the reduction of SOCE induced EPC dysfunction during AS, potentially through downregulation of store-operated calcium channel (SOCC) components and impaired eNOS activity. Approaches aimed at reestablishing SOCE activity may thus improve the function of EPCs during AS.
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Affiliation(s)
- Lian-You Wang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Ji-Hang Zhang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Jie Yu
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Jie Yang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Meng-Yang Deng
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Hua-Li Kang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
| | - Lan Huang
- Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University , Chongqing, People's Republic of China
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178
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Kanageswaran N, Demond M, Nagel M, Schreiner BSP, Baumgart S, Scholz P, Altmüller J, Becker C, Doerner JF, Conrad H, Oberland S, Wetzel CH, Neuhaus EM, Hatt H, Gisselmann G. Deep sequencing of the murine olfactory receptor neuron transcriptome. PLoS One 2015; 10:e0113170. [PMID: 25590618 PMCID: PMC4295871 DOI: 10.1371/journal.pone.0113170] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/25/2014] [Indexed: 11/18/2022] Open
Abstract
The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation.
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Affiliation(s)
| | - Marilen Demond
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- University Duisburg-Essen, Institute of Medical Radiation Biology, Essen, Germany
| | - Maximilian Nagel
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | - Sabrina Baumgart
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Paul Scholz
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | | | - Julia F. Doerner
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Heike Conrad
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- Cluster of Excellence and DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Sonja Oberland
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian H. Wetzel
- University of Regensburg, Department of Psychiatry and Psychotherapy, Molecular Neurosciences, Regensburg, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hanns Hatt
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Günter Gisselmann
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
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179
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Baba Y, Kurosaki T. Role of Calcium Signaling in B Cell Activation and Biology. Curr Top Microbiol Immunol 2015; 393:143-174. [PMID: 26369772 DOI: 10.1007/82_2015_477] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase in intracellular levels of calcium ions (Ca2+) is one of the key triggering signals for the development of B cell response to the antigen. The diverse Ca2+ signals finely controlled by multiple factors participate in the regulation of gene expression, B cell development, and effector functions. B cell receptor (BCR)-initiated Ca2+ mobilization is sourced from two pathways: one is the release of Ca2+ from the intracellular stores, endoplasmic reticulum (ER), and other is the prolonged influx of extracellular Ca2+ induced by depleting the stores via store-operated calcium entry (SOCE) and calcium release-activated calcium (CRAC) channels. The identification of stromal interaction molecule 1(STIM1), the ER Ca2+ sensor, and Orai1, a key subunit of the CRAC channel pore, has now provided the tools to understand the mode of Ca2+ influx regulation and physiological relevance. Herein, we discuss our current understanding of the molecular mechanisms underlying BCR-triggered Ca2+ signaling as well as its contribution to the B cell biological processes and diseases.
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Affiliation(s)
- Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan. .,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan.
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan.,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan
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180
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Maléth J, Choi S, Muallem S, Ahuja M. Translocation between PI(4,5)P2-poor and PI(4,5)P2-rich microdomains during store depletion determines STIM1 conformation and Orai1 gating. Nat Commun 2014; 5:5843. [PMID: 25517631 PMCID: PMC4270102 DOI: 10.1038/ncomms6843] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/12/2014] [Indexed: 01/04/2023] Open
Abstract
The Orai1-STIM1 current undergoes slow Ca(2+)-dependent inactivation (SCDI) mediated by the binding of SARAF to STIM1. Here we report the use of SCDI by SARAF as a probe of the conformation and microdomain localization of the Orai1-STIM1 complex. We find that the interaction of STIM1 with Orai1 carboxyl terminus (C terminus) and the STIM1 K-domain are required for the interaction of SARAF with STIM1 and SCDI. STIM1-Orai1 must be in a PM/ER microdomain tethered by E-Syt1, stabilized by septin4 and enriched in PI(4,5)P2 for STIM1-SARAF interaction. Targeting STIM1 to PI(4,5)P2-rich and -poor microdomains reveals that SARAF-dependent SCDI is observed only when STIM1-Orai1 are within the PI(4,5)P2-rich microdomain. Notably, store depletion results in transient localization of STIM1-Orai1 in the PI(4,5)P2-poor microdomain, which then translocates to the PI(4,5)P2-rich domain. These findings reveal the role of PM/ER tethers in the regulation of Orai1 function and a mode of regulation by PI(4,5)P2 involving translocation between PI(4,5)P2 microdomains.
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Affiliation(s)
- Jozsef Maléth
- 1] Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, Maryland 20892, USA [2] First Department of Medicine, University of Szeged, H-6725 Szeged, Hungary
| | - Seok Choi
- 1] Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, Maryland 20892, USA [2] Department of Physiology, College of Medicine, Chosun University, Chosun 501-375, South Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, Maryland 20892, USA
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, Maryland 20892, USA
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181
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Taha S, Aljishi M, Alsharoqi I, Bakhiet M. Differential upregulation of the hypothetical transmembrane protein 66 ( TMEM66) in multiple sclerosis patients with potential inflammatory response. Biomed Rep 2014; 3:98-104. [PMID: 25469256 DOI: 10.3892/br.2014.390] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/15/2014] [Indexed: 01/06/2023] Open
Abstract
The prevalence of multiple sclerosis (MS) in the Gulf region has markedly increased during the last decade, but the mechanisms of the disease have not been investigated. The present study aimed to understand the molecular processes involved in the disease development of the recently emerged MS in this population using microarray technology to investigate differentially-expressed novel genes in MS patients compared to healthy-matched subjects. The expression of the upregulated genes was confirmed by quantitative polymerase chain reaction (qPCR). Furthermore, gene cloning, protein expression and purification were performed followed by testing of the obtained recombinant protein on biological assays, including cell proliferation and cytokine mRNA detection by reverse transcriptase-qPCR. The results showed that out of ~50,000 genes, the hypothetical transmembrane protein-66 gene (TMEM66) exhibited a 3 times higher expression in MS patients compared to healthy subjects. The TMEM66 gene was cloned and its protein showed marked immunological activity relevant to MS since significant proliferation (P<0.05) and augmented induction of the proinflammatory cytokines, interleukin (IL)-6, interferon-γ, tumor necrosis factor-α, and the chemokines, chemokine ligand 5/chemokine receptor 5, macrophage inflammatory protein 1α (MIP-1α) and MIP-1β were recorded, but not the anti-inflammatory cytokines, IL-4 or IL-2. In conclusion, TMEM66 may be associated with the molecular events of MS and may be considered as an MS biomarker for future personalized medicine management approaches.
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Affiliation(s)
- Safa Taha
- Department of Molecular Medicine, Princess Al-Jawhara Center for Genetics and Inherited Diseases, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
| | - Muna Aljishi
- Department of Molecular Medicine, Princess Al-Jawhara Center for Genetics and Inherited Diseases, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
| | - Isa Alsharoqi
- Department of Clinical Neurosciences, Salmaniya Medical Complex, Manama, Bahrain
| | - Moiz Bakhiet
- Department of Molecular Medicine, Princess Al-Jawhara Center for Genetics and Inherited Diseases, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain
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182
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Zhou X, Li J, Yang W. Calcium/calmodulin-dependent protein kinase II regulates cyclooxygenase-2 expression and prostaglandin E2 production by activating cAMP-response element-binding protein in rat peritoneal macrophages. Immunology 2014; 143:287-99. [PMID: 24773364 DOI: 10.1111/imm.12309] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 04/19/2014] [Accepted: 04/24/2014] [Indexed: 12/17/2022] Open
Abstract
Prostaglandin E2 (PGE2 ) is an important inducer of inflammation, which is also closely linked to the progress of tumours. In macrophages, PGE2 production is regulated by arachidonic acid release and cyclooxygenase-2 (COX-2) expression. In the present study, we found that COX-2 expression can be achieved by activating Ca(2+) /Calmodulin (CaM)-dependent protein kinase II (CaMKII) and cAMP-response element-binding protein (CREB) in rat peritoneal macrophages. Our results indicated that lipopolysaccharide and PMA could elicit the transient increase of the concentration of intracellular free calcium ions ([Ca(2+) ]i ), which induced activation of CaMKs with the presence of CaM. The subtype of CaMKs, CaMKII, then triggered the activation of CREB, which elevated COX-2 expression and PGE2 production in a chronological order. These results suggested that Ca(2+) /CaM-dependent CaMKII plays an important role in mediating COX-2 expression and PGE2 production by activating CREB in macrophages. The study also provides more useful information to clarify the mechanism of calcium regulation of PGE2 production, which plays an essential role in inflammation and cancers.
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Affiliation(s)
- Xueyuan Zhou
- Department of Biophysics, School of Physics, Nankai University, Tianjin, China; Clinic Service Program, Leidos Biomedical Research Inc., Frederick, MD, USA
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183
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Shim AHR, Tirado-Lee L, Prakriya M. Structural and functional mechanisms of CRAC channel regulation. J Mol Biol 2014; 427:77-93. [PMID: 25284754 DOI: 10.1016/j.jmb.2014.09.021] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/18/2014] [Accepted: 09/25/2014] [Indexed: 11/29/2022]
Abstract
In many animal cells, stimulation of cell surface receptors coupled to G proteins or tyrosine kinases mobilizes Ca(2+) influx through store-operated Ca(2+)-release-activated Ca(2+) (CRAC) channels. The ensuing Ca(2+) entry regulates a wide variety of effector cell responses including transcription, motility, and proliferation. The physiological importance of CRAC channels for human health is underscored by studies indicating that mutations in CRAC channel genes produce a spectrum of devastating diseases including chronic inflammation, muscle weakness, and a severe combined immunodeficiency syndrome. Moreover, from a basic science perspective, CRAC channels exhibit a unique biophysical fingerprint characterized by exquisite Ca(2+) selectivity, store-operated gating, and distinct pore properties and therefore serve as fascinating model ion channels for understanding the biophysical mechanisms of Ca(2+) selectivity and channel opening. Studies in the last two decades have revealed the cellular and molecular choreography of the CRAC channel activation process, and it is now established that opening of CRAC channels is governed through direct interactions between the pore-forming Orai proteins and the endoplasmic reticulum Ca(2+) sensors STIM1 and STIM2. In this review, we summarize the functional and structural mechanisms of CRAC channel regulation, focusing on recent advances in our understanding of the conformational and structural dynamics of CRAC channel gating.
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Affiliation(s)
- Ann Hye-Ryong Shim
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Leidamarie Tirado-Lee
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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184
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Maggio N, Vlachos A. Synaptic plasticity at the interface of health and disease: New insights on the role of endoplasmic reticulum intracellular calcium stores. Neuroscience 2014; 281:135-46. [PMID: 25264032 DOI: 10.1016/j.neuroscience.2014.09.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 10/24/2022]
Abstract
Work from the past 40years has unraveled a wealth of information on the cellular and molecular mechanisms underlying synaptic plasticity and their relevance in physiological brain function. At the same time, it has been recognized that a broad range of neurological diseases may be accompanied by severe alterations in synaptic plasticity, i.e., 'maladaptive synaptic plasticity', which could initiate and sustain the remodeling of neuronal networks under pathological conditions. Nonetheless, our current knowledge on the specific contribution and interaction of distinct forms of synaptic plasticity (including metaplasticity and homeostatic plasticity) in the context of pathological brain states remains limited. This review focuses on recent experimental evidence, which highlights the fundamental role of endoplasmic reticulum-mediated Ca(2+) signals in modulating the duration, direction, extent and type of synaptic plasticity. We discuss the possibility that intracellular Ca(2+) stores may regulate synaptic plasticity and hence behavioral and cognitive functions at the interface between physiology and pathology.
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Affiliation(s)
- N Maggio
- Talpiot Medical Leadership Program, Department of Neurology, The Chaim Sheba Medical Center, 52621 Tel HaShomer, Israel
| | - A Vlachos
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
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185
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Billaud M, Lohman AW, Johnstone SR, Biwer LA, Mutchler S, Isakson BE. Regulation of cellular communication by signaling microdomains in the blood vessel wall. Pharmacol Rev 2014; 66:513-69. [PMID: 24671377 DOI: 10.1124/pr.112.007351] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.
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Affiliation(s)
- Marie Billaud
- Dept. of Molecular Physiology and Biophysics, University of Virginia School of Medicine, PO Box 801394, Charlottesville, VA 22902.
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186
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Srikanth S, Gwack Y. Molecular regulation of the pore component of CRAC channels, Orai1. CURRENT TOPICS IN MEMBRANES 2014; 71:181-207. [PMID: 23890116 DOI: 10.1016/b978-0-12-407870-3.00008-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Store-operated Ca(2+) entry (SOCE) is a fundamental mechanism ubiquitously employed by cells to elevate intracellular Ca(2+) concentrations ([Ca(2+)]i). Increased intracellular Ca(2+) ions act as a second messenger that can stimulate a variety of downstream signaling pathways affecting proliferation, secretion, differentiation, and death of cells. In immune cells, immune receptor stimulation induces endoplasmic reticulum Ca(2+) store depletion that subsequently activates Ca(2+)-release-activated-Ca(2+) (CRAC) channels, a prototype of store-operated Ca(2+) (SOC) channels. Identification of Orai1 as the pore subunit of CRAC channels has provided the much-needed molecular tool to dissect the mechanism of activation and regulation of these channels. In this review, we discuss the recent advances in understanding the regulatory mechanisms and posttranslational modifications that regulate diverse aspects of CRAC channel function.
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Affiliation(s)
- Sonal Srikanth
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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187
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Hoth M, Niemeyer BA. The neglected CRAC proteins: Orai2, Orai3, and STIM2. CURRENT TOPICS IN MEMBRANES 2014; 71:237-71. [PMID: 23890118 DOI: 10.1016/b978-0-12-407870-3.00010-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Plasma-membrane-localized Orai1 ion channel subunits interacting with ER-localized STIM1 molecules comprise the major subunit composition responsible for calcium release-activated calcium channels. STIM1 "translates" the Ca(2+) store content into Orai1 activity, making it a store-operated channel. Surprisingly, in addition to being the physical activator, STIM1 also modulates Orai1 properties, including its inactivation and permeation (see Chapter 1). STIM1 is thus more than a pure Orai1 activator. Within the past 7 years following the discovery of STIM and Orai proteins, the molecular mechanisms of STIM1/Orai1 activity and their functional importance have been studied in great detail. Much less is currently known about the other isoforms STIM2, Orai2, and Orai3. In this chapter, we summarize the current knowledge about STIM2, Orai2, and Orai3 properties and function. Are these homologues mainly modulators of predominantly STIM1/Orai1-mediated complexes or do store-dependent or -independent functions such as regulation of basal Ca(2+) concentration and activation of Orai3-containing complexes by arachidonic acid or by estrogen receptors point toward their "true" physiological function? Is Orai2 the Orai1 of neurons? A major focus of the review is on the functional relevance of STIM2, Orai2, and Orai3, some of which still remains speculative.
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Affiliation(s)
- Markus Hoth
- Department of Biophysics, Saarland University, Homburg, Germany
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188
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Choi S, Maleth J, Jha A, Lee KP, Kim MS, So I, Ahuja M, Muallem S. The TRPCs-STIM1-Orai interaction. Handb Exp Pharmacol 2014; 223:1035-54. [PMID: 24961979 DOI: 10.1007/978-3-319-05161-1_13] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ca(2+) signaling entails receptor-stimulated Ca(2+) release from the ER stores that serves as a signal to activate Ca(2+) influx channels present at the plasma membrane, the store-operated Ca(2+) channels (SOCs). The two known SOCs are the Orai and TRPC channels. The SOC-dependent Ca(2+) influx mediates and sustains virtually all Ca(2+)-dependent regulatory functions. The signal that transmits the Ca(2+) content of the ER stores to the plasma membrane is the ER resident, Ca(2+)-binding protein STIM1. STIM1 is a multidomain protein that clusters and dimerizes in response to Ca(2+) store depletion leading to activation of Orai and TRPC channels. Activation of the Orais by STIM1 is obligatory for their function as SOCs, while TRPC channels can function as both STIM1-dependent and STIM1-independent channels. Here we discuss the different mechanisms by which STIM1 activates the Orai and TRPC channels, the emerging specific and non-overlapping physiological functions of Ca(2+) influx mediated by the two channel types, and argue that the TRPC channels should be the preferred therapeutic target to control the toxic effect of excess Ca(2+) influx.
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Affiliation(s)
- Seok Choi
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
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189
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Calcium signaling in B cells: regulation of cytosolic Ca2+ increase and its sensor molecules, STIM1 and STIM2. Mol Immunol 2013; 62:339-43. [PMID: 24246800 DOI: 10.1016/j.molimm.2013.10.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/27/2013] [Accepted: 10/08/2013] [Indexed: 01/30/2023]
Abstract
Calcium signals are crucial for diverse cellular functions including adhesion, differentiation, proliferation, effector functions and gene expression. After engagement of the B cell receptor, the intracellular calcium ion (Ca(2+)) concentration is increased promoting the activation of various signaling cascades. While elevated Ca(2+) in the cytosol initially comes from the endoplasmic reticulum (ER), a continuous influx of extracellular Ca(2+) is required to maintain the increased level of cytosolic Ca(2+). Store-operated Ca(2+) entry manages this process, which is regulated by an ER calcium sensor, stromal interaction molecule (STIM). STIM proteins sense changes in the levels of Ca(2+) stored within the ER lumen and regulates the Ca(2+)-release activated Ca(2+) channel in the plasma membrane. This review focuses on the signaling pathways leading to Ca(2+) influx and the role of Ca(2+) signals in B cell functions.
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190
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Cully TR, Launikonis BS. Store-operated Ca²⁺ entry is not required for store refilling in skeletal muscle. Clin Exp Pharmacol Physiol 2013; 40:338-44. [PMID: 23517302 DOI: 10.1111/1440-1681.12078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/27/2013] [Accepted: 03/03/2013] [Indexed: 11/28/2022]
Abstract
The present review describes store-operated Ca²⁺ entry (SOCE) in skeletal muscle. Fundamental discoveries in the field of skeletal muscle SOCE are described and the techniques that were used to make these. The advantages and limitations in these techniques are discussed to provide a means of questioning and determining the physiological role(s) of SOCE in skeletal muscle. It is concluded that SOCE has little or no role in the filling of the sarcoplasmic reticulum with Ca²⁺ at rest or during a single contracture. It is likely that SOCE is activated during fatigue, although direct measurements of SOCE are lacking and the physiological significance remains uncertain.
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Affiliation(s)
- Tanya R Cully
- School of Biomedical Sciences, The University of Queensland, Brisbane, Qld, Australia
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191
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Lam AK, Galione A. The endoplasmic reticulum and junctional membrane communication during calcium signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2542-59. [DOI: 10.1016/j.bbamcr.2013.06.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/03/2013] [Accepted: 06/03/2013] [Indexed: 12/13/2022]
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192
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Cogger VC, Svistounov D, Warren A, Zykova S, Melvin RG, Solon-Biet SM, O'Reilly JN, McMahon AC, Ballard JWO, De Cabo R, Le Couteur DG, Lebel M. Liver aging and pseudocapillarization in a Werner syndrome mouse model. J Gerontol A Biol Sci Med Sci 2013; 69:1076-86. [PMID: 24149428 DOI: 10.1093/gerona/glt169] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Werner syndrome is a progeric syndrome characterized by premature atherosclerosis, diabetes, cancer, and death in humans. The knockout mouse model created by deletion of the RecQ helicase domain of the mouse Wrn homologue gene (Wrn(∆hel/∆hel)) is of great interest because it develops atherosclerosis and hypertriglyceridemia, conditions associated with aging liver and sinusoidal changes. Here, we show that Wrn(∆hel/∆hel) mice exhibit increased extracellular matrix, defenestration, decreased fenestration diameter, and changes in markers of liver sinusoidal endothelial cell inflammation, consistent with age-related pseudocapilliarization. In addition, hepatocytes are larger, have increased lipofuscin deposition, more frequent nuclear morphological anomalies, decreased mitochondria number, and increased mitochondrial diameter compared to wild-type mice. The Wrn(∆hel/∆hel) mice also have altered mitochondrial function and altered nuclei. Microarray data revealed that the Wrn(∆hel/∆hel) genotype does not affect the expression of many genes within the isolated hepatocytes or liver sinusoidal endothelial cells. This study reveals that Wrn(∆hel/∆hel) mice have accelerated typical age-related liver changes including pseudocapillarization. This confirms that pseudocapillarization of the liver sinusoid is a consistent feature of various aging models. Moreover, it implies that DNA repair may be implicated in normal aging changes in the liver.
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Affiliation(s)
- Victoria C Cogger
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Dmitri Svistounov
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Alessandra Warren
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Svetlana Zykova
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Richard G Melvin
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, Australia
| | - Samantha M Solon-Biet
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia. School of Biological Sciences, University of Sydney, New South Wales, Australia
| | - Jennifer N O'Reilly
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Aisling C McMahon
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - J William O Ballard
- School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, Australia
| | - Rafa De Cabo
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - David G Le Couteur
- Centre for Education and Research on Aging and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, New South Wales, Australia
| | - Michel Lebel
- Centre de Recherche en Cancérologie de l'Université Laval, Hôpital Hotel-Dieu de Quebec, Canada
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193
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Wang C, Funk CC, Eddy JA, Price ND. Transcriptional analysis of aggressiveness and heterogeneity across grades of astrocytomas. PLoS One 2013; 8:e76694. [PMID: 24146911 PMCID: PMC3795736 DOI: 10.1371/journal.pone.0076694] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 08/27/2013] [Indexed: 11/19/2022] Open
Abstract
Astrocytoma is the most common glioma, accounting for half of all primary brain and spinal cord tumors. Late detection and the aggressive nature of high-grade astrocytomas contribute to high mortality rates. Though many studies identify candidate biomarkers using high-throughput transcriptomic profiling to stratify grades and subtypes, few have resulted in clinically actionable results. This shortcoming can be attributed, in part, to pronounced lab effects that reduce signature robustness and varied individual gene expression among patients with the same tumor. We addressed these issues by uniformly preprocessing publicly available transcriptomic data, comprising 306 tumor samples from three astrocytoma grades (Grade 2, 3, and 4) and 30 non-tumor samples (normal brain as control tissues). Utilizing Differential Rank Conservation (DIRAC), a network-based classification approach, we examined the global and individual patterns of network regulation across tumor grades. Additionally, we applied gene-based approaches to identify genes whose expression changed consistently with increasing tumor grade and evaluated their robustness across multiple studies using statistical sampling. Applying DIRAC, we observed a global trend of greater network dysregulation with increasing tumor aggressiveness. Individual networks displaying greater differences in regulation between adjacent grades play well-known roles in calcium/PKC, EGF, and transcription signaling. Interestingly, many of the 90 individual genes found to monotonically increase or decrease with astrocytoma grade are implicated in cancer-affected processes such as calcium signaling, mitochondrial metabolism, and apoptosis. The fact that specific genes monotonically increase or decrease with increasing astrocytoma grade may reflect shared oncogenic mechanisms among phenotypically similar tumors. This work presents statistically significant results that enable better characterization of different human astrocytoma grades and hopefully can contribute towards improvements in diagnosis and therapy choices. Our results also identify a number of testable hypotheses relating to astrocytoma etiology that may prove helpful in developing much-needed biomarkers for earlier disease detection.
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Affiliation(s)
- Chunjing Wang
- Institute for Systems Biology, Seattle, Washington, United States of America
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois, United States of America
| | - Cory C. Funk
- Institute for Systems Biology, Seattle, Washington, United States of America
| | - James A. Eddy
- Institute for Systems Biology, Seattle, Washington, United States of America
- Department of Bioengineering, University of Illinois, Urbana, Illinois, United States of America
| | - Nathan D. Price
- Institute for Systems Biology, Seattle, Washington, United States of America
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, Illinois, United States of America
- Department of Bioengineering, University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
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194
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Abstract
Ca(2+) influx via store-operated Ca(2+) release activated Ca(2+) (CRAC) channels represents a main signaling pathway for T-cell activation as well as mast-cell degranulation. The ER-located Ca(2+)-sensor, STIM1 and the Ca(2+)-selective ion pore, Orai1 in the membrane are sufficient to fully reconstitute CRAC currents. Their identification, but even more the recent structural resolution of both proteins by X-ray crystallography has substantially advanced the understanding of the activation mechanism of CRAC channels. In this review, we provide a detailed description of the STIM1/Orai1 signaling pathway thereby focusing on the critical domains mediating both, intra- as well as intermolecular interactions and on the ion permeation pathway. Based on the results of functional studies as well as the recently published crystal structures, we portray a mechanistic view of the steps in the CRAC channel signaling cascade ranging from STIM1 oligomerization over STIM1-Orai1 coupling to the ultimate Orai1 channel activation and permeation.
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Affiliation(s)
- Marc Fahrner
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Isabella Derler
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Isaac Jardin
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Christoph Romanin
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
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195
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Jairaman A, Prakriya M. Molecular pharmacology of store-operated CRAC channels. Channels (Austin) 2013; 7:402-14. [PMID: 23807116 DOI: 10.4161/chan.25292] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Calcium influx through store-operated Ca(2+) release-activated Ca(2+) channels (CRAC channels) is a well-defined mechanism of generating cellular Ca(2+) elevations that regulates many functions including gene expression, exocytosis and cell proliferation. The identifications of the ER Ca(2+) sensing proteins, STIM1-2 and the CRAC channel proteins, Orai1-3, have led to improved understanding of the physiological roles and the activation mechanism of CRAC channels. Defects in CRAC channel function are associated with serious human diseases such as immunodeficiency and auto-immunity. In this review, we discuss several pharmacological modulators of CRAC channels, focusing specifically on the molecular mechanism of drug action and their utility in illuminating the mechanism of CRAC channel operation and their physiological roles in different cells.
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Affiliation(s)
- Amit Jairaman
- Department of Molecular Pharmacology and Biological Chemistry; Northwestern University, Feinberg School of Medicine; Chicago, IL USA
| | - Murali Prakriya
- Department of Molecular Pharmacology and Biological Chemistry; Northwestern University, Feinberg School of Medicine; Chicago, IL USA
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196
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Collins HE, Zhu-Mauldin X, Marchase RB, Chatham JC. STIM1/Orai1-mediated SOCE: current perspectives and potential roles in cardiac function and pathology. Am J Physiol Heart Circ Physiol 2013; 305:H446-58. [PMID: 23792674 PMCID: PMC3891250 DOI: 10.1152/ajpheart.00104.2013] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Store-operated Ca²⁺ entry (SOCE) is critical for Ca²⁺ signaling in nonexcitable cells; however, its role in the regulation of cardiomyocyte Ca²⁺ homeostasis has only recently been investigated. The increased understanding of the role of stromal interaction molecule 1 (STIM1) in regulating SOCE combined with recent studies demonstrating the presence of STIM1 in cardiomyocytes provides support that this pathway co-exists in the heart with the more widely recognized Ca²⁺ handling pathways associated with excitation-contraction coupling. There is now substantial evidence that STIM1-mediated SOCE plays a key role in mediating cardiomyocyte hypertrophy, both in vitro and in vivo, and there is growing support for the contribution of SOCE to Ca²⁺ overload associated with ischemia/reperfusion injury. Here, we provide an overview of our current understanding of the molecular regulation of SOCE and discuss the evidence supporting the role of STIM1/Orai1-mediated SOCE in regulating cardiomyocyte function.
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Affiliation(s)
- Helen E Collins
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
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197
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Jha A, Ahuja M, Maléth J, Moreno CM, Yuan JP, Kim MS, Muallem S. The STIM1 CTID domain determines access of SARAF to SOAR to regulate Orai1 channel function. ACTA ACUST UNITED AC 2013; 202:71-9. [PMID: 23816623 PMCID: PMC3704993 DOI: 10.1083/jcb.201301148] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two distinct lobes in the C-terminal inhibitory domain in STIM1 determine access of the inhibitor SARAF to the activating SOAR domain to regulate the slow Ca2+-dependent inactivation of Orai1. Ca2+ influx by store-operated Ca2+ channels (SOCs) mediates all Ca2+-dependent cell functions, but excess Ca2+ influx is highly toxic. The molecular components of SOC are the pore-forming Orai1 channel and the endoplasmic reticulum Ca2+ sensor STIM1. Slow Ca2+-dependent inactivation (SCDI) of Orai1 guards against cell damage, but its molecular mechanism is unknown. Here, we used homology modeling to identify a conserved STIM1(448–530) C-terminal inhibitory domain (CTID), whose deletion resulted in spontaneous clustering of STIM1 and full activation of Orai1 in the absence of store depletion. CTID regulated SCDI by determining access to and interaction of the STIM1 inhibitor SARAF with STIM1 Orai1 activation region (SOAR), the STIM1 domain that activates Orai1. CTID had two lobes, STIM1(448–490) and STIM1(490–530), with distinct roles in mediating access of SARAF to SOAR. The STIM1(448–490) lobe restricted, whereas the STIM1(490–530) lobe directed, SARAF to SOAR. The two lobes cooperated to determine the features of SCDI. These findings highlight the central role of STIM1 in SCDI and provide a molecular mechanism for SCDI of Orai1.
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Affiliation(s)
- Archana Jha
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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198
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Motiani RK, Stolwijk JA, Newton RL, Zhang X, Trebak M. Emerging roles of Orai3 in pathophysiology. Channels (Austin) 2013; 7:392-401. [PMID: 23695829 DOI: 10.4161/chan.24960] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Calcium (Ca(2+)) is a ubiquitous second messenger that regulates a plethora of physiological functions. Deregulation of calcium homeostasis has been reported in a wide variety of pathological conditions including cardiovascular disorders, cancer and neurodegenerative diseases. One of the most ubiquitous pathways involved in regulated Ca(2+) influx into cells is the store-operated Ca(2+) entry (SOCE) pathway. In 2006, Orai1 was identified as the channel protein that mediates SOCE in immune cells. Orai1 has two mammalian homologs, Orai2 and Orai3. Although Orai1 has been the most widely studied Orai isoform, Orai3 has recently received significant attention. Under native conditions, Orai3 was demonstrated to be an important component of store-independent arachidonate-regulated Ca(2+) (ARC) entry in HEK293 cells, and more recently of a store-independent leukotrieneC4-regulated Ca(2+) (LRC) entry pathway in vascular smooth muscle cells. Recent studies have shown upregulation of Orai3 in estrogen receptor-expressing breast cancers and a critical role for Orai3 in breast cancer development in immune-compromised mice. Orai3 upregulation was also shown to contribute to vascular smooth muscle remodeling and neointimal hyperplasia caused by vascular injury. Furthermore, Orai3 has been shown to contribute to proliferation of effector T-lymphocytes under oxidative stress. In this review, we will discuss the role of Orai3 in reported pathophysiological conditions and will contribute ideas on the potential role of Orai3 in native Ca(2+) signaling pathways and human disease.
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Affiliation(s)
- Rajender K Motiani
- Nanobioscience Constellation; College of Nanoscale Science and Engineering (CNSE); University at Albany; State University of New York; Albany, NY USA; DST-INSPIRE Faculty; Institute of Genomics and Integrative Biology (IGIB); New Delhi, India
| | - Judith A Stolwijk
- Nanobioscience Constellation; College of Nanoscale Science and Engineering (CNSE); University at Albany; State University of New York; Albany, NY USA
| | - Rachel L Newton
- Nanobioscience Constellation; College of Nanoscale Science and Engineering (CNSE); University at Albany; State University of New York; Albany, NY USA
| | - Xuexin Zhang
- Nanobioscience Constellation; College of Nanoscale Science and Engineering (CNSE); University at Albany; State University of New York; Albany, NY USA
| | - Mohamed Trebak
- Nanobioscience Constellation; College of Nanoscale Science and Engineering (CNSE); University at Albany; State University of New York; Albany, NY USA
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199
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NLF-1 delivers a sodium leak channel to regulate neuronal excitability and modulate rhythmic locomotion. Neuron 2013; 77:1069-82. [PMID: 23522043 DOI: 10.1016/j.neuron.2013.01.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2013] [Indexed: 11/22/2022]
Abstract
A cation channel NCA/UNC-79/UNC-80 affects neuronal activity. We report here the identification of a conserved endoplasmic reticulum protein NLF-1 (NCA localization factor-1) that regulates neuronal excitability and locomotion through the NCA channel. In C. elegans, the loss of either NLF-1 or NCA leads to a reduced sodium leak current, and a hyperpolarized resting membrane potential in premotor interneurons. This results in a decreased premotor interneuron activity that reduces the initiation and sustainability of rhythmic locomotion. NLF-1 promotes axonal localization of all NCA reporters. Its mouse homolog mNLF-1 functionally substitutes for NLF-1 in C. elegans, interacts with the mammalian sodium leak channel NALCN in vitro, and potentiates sodium leak currents in primary cortical neuron cultures. Taken together, an ER protein NLF-1 delivers a sodium leak channel to maintain neuronal excitability and potentiates a premotor interneuron network critical for C. elegans rhythmic locomotion.
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200
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Cui W, Ma J, Wang X, Yang W, Zhang J, Ji Q. Free fatty acid induces endoplasmic reticulum stress and apoptosis of β-cells by Ca2+/calpain-2 pathways. PLoS One 2013; 8:e59921. [PMID: 23527285 PMCID: PMC3604010 DOI: 10.1371/journal.pone.0059921] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 02/19/2013] [Indexed: 12/28/2022] Open
Abstract
Dysfunction of β-cells is a major characteristic in the pathogenesis of type 2 diabetes mellitus (T2DM). The combination of obesity and T2DM is associated with elevated plasma free fatty acids (FFAs). However, molecular mechanisms linking FFAs to β-cell dysfunction remain poorly understood. In the present study, we identified that the major endoplasmic reticulum stress (ERS) marker, Grp78 and ERS-induced apoptotic factor, CHOP, were time-dependently increased by exposure of β-TC3 cells to FFA. The expression of ATF6 and the phosphorylation levels of PERK and IRE1, which trigger ERS signaling, markedly increased after FFA treatments. FFA treatments increased cell apoptosis by inducing ERS in β-TC3 cells. We also found that FFA-induced ERS was mediated by the store-operated Ca2+ entry through promoting the association of STIM1 and Orai1. Moreover, calpain-2 was required for FFA-induced expression of CHOP and activation of caspase-12 and caspase-3, thus promoting cell apoptosis in β-TC3 cells. Together, these results reveal pivotal roles for Ca2+/calpain-2 pathways in modulating FFA-induced β-TC3 cell ERS and apoptosis.
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Affiliation(s)
- Wei Cui
- Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Jie Ma
- Department of Neurosurgery, Tangdu Hospital, Forth Military Medical University, Xi’an, China
| | - Xingqin Wang
- Department of Neurosurgery, Tangdu Hospital, Forth Military Medical University, Xi’an, China
| | - Wenjuan Yang
- Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Jing Zhang
- No. 371 Central Hospital of People’s Liberation Army, Xinxiang, China
| | - Qiuhe Ji
- Department of Endocrinology and Metabolism, Xijing Hospital, Fourth Military Medical University, Xi’an, China
- * E-mail:
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