1
|
Bieber M, Schuhmann MK, Bellut M, Stegner D, Heinze KG, Pham M, Nieswandt B, Stoll G. Blockade of Platelet Glycoprotein Ibα Augments Neuroprotection in Orai2-Deficient Mice during Middle Cerebral Artery Occlusion. Int J Mol Sci 2022; 23:9496. [PMID: 36012752 DOI: 10.3390/ijms23169496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/21/2022] Open
Abstract
During ischemic stroke, infarct growth before recanalization diminishes functional outcome. Hence, adjunct treatment options to protect the ischemic penumbra before recanalization are eagerly awaited. In experimental stroke targeting two different pathways conferred protection from penumbral tissue loss: (1) enhancement of hypoxic tolerance of neurons by deletion of the calcium channel subunit Orai2 and (2) blocking of detrimental lymphocyte–platelet responses. However, until now, no preclinical stroke study has assessed the potential of combining neuroprotective with anti-thrombo-inflammatory interventions to augment therapeutic effects. We induced focal cerebral ischemia in Orai2-deficient (Orai2-/-) mice by middle cerebral artery occlusion (MCAO). Animals were treated with anti-glycoprotein Ib alpha (GPIbα) Fab fragments (p0p/B Fab) blocking GPIbα–von Willebrand factor (vWF) interactions. Rat immunoglobulin G (IgG) Fab was used as the control treatment. The extent of infarct growth before recanalization was assessed at 4 h after MCAO. Moreover, infarct volumes were determined 6 h after recanalization (occlusion time: 4 h). Orai2 deficiency significantly halted cerebral infarct progression under occlusion. Inhibition of platelet GPIbα further reduced primary infarct growth in Orai2-/- mice. During ischemia–reperfusion, upon recanalization, mice were likewise protected. All in all, we show that neuroprotection in Orai2-/- mice can be augmented by targeting thrombo-inflammation. This supports the clinical development of combined neuroprotective/anti-platelet strategies in hyper-acute stroke.
Collapse
|
2
|
Augustynek B, Gyimesi G, Dernič J, Sallinger M, Albano G, Klesse GJ, Kandasamy P, Grabmayr H, Frischauf I, Fuster DG, Peinelt C, Hediger MA, Bhardwaj R. Discovery of novel gating checkpoints in the Orai1 calcium channel by systematic analysis of constitutively active mutants of its paralogs and orthologs. Cell Calcium 2022; 105:102616. [PMID: 35792401 DOI: 10.1016/j.ceca.2022.102616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 11/24/2022]
Abstract
In humans, there are three paralogs of the Orai Ca2+ channel that form the core of the store-operated calcium entry (SOCE) machinery. While the STIM-mediated gating mechanism of Orai channels is still under active investigation, several artificial and natural variants are known to cause constitutive activity of the human Orai1 channel. Surprisingly, little is known about the conservation of the gating checkpoints among the different human Orai paralogs and orthologs in other species. In our work, we show that the mutation corresponding to the activating mutation H134A in transmembrane helix 2 (TM2) of human Orai1 also activates Orai2 and Orai3, likely via a similar mechanism. However, this cross-paralog conservation does not apply to the "ANSGA" nexus mutations in TM4 of human Orai1, which is reported to mimic the STIM1-activated state of the channel. In investigating the mechanistic background of these differences, we identified two positions, H171 and F246 in human Orai1, that are not conserved among paralogs and that seem to be crucial for the channel activation triggered by the "ANSGA" mutations in Orai1. However, mutations of the same residues still allow gating of Orai1 by STIM1, suggesting that the ANSGA mutant of Orai1 may not be a surrogate for the STIM1-activated state of the Orai1 channel. Our results shed new light on these important gating checkpoints and show that the gating mechanism of Orai channels is affected by multiple factors that are not necessarily conserved among orai homologs, such as the TM4-TM3 coupling.
Collapse
Affiliation(s)
- Bartłomiej Augustynek
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Gergely Gyimesi
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Jan Dernič
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Matthias Sallinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Giuseppe Albano
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Gabriel J Klesse
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Palanivel Kandasamy
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Herwig Grabmayr
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Daniel G Fuster
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland
| | - Christine Peinelt
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland
| | - Matthias A Hediger
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland.
| | - Rajesh Bhardwaj
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Freiburgstrasse 15, CH-3010 Bern, Switzerland; Current address: Signal Transduction Laboratory, National Institute of Environmental Health Sciences, NIH, 111 TW Alexander Drive, NC 27709, USA.
| |
Collapse
|
3
|
Sanchez-Collado J, Lopez JJ, Cantonero C, Jardin I, Regodón S, Redondo PC, Gordillo J, Smani T, Salido GM, Rosado JA. Orai2 Modulates Store-Operated Ca(2+) Entry and Cell Cycle Progression in Breast Cancer Cells. Cancers (Basel) 2021; 14. [PMID: 35008277 DOI: 10.3390/cancers14010114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/07/2021] [Accepted: 12/23/2021] [Indexed: 12/15/2022] Open
Abstract
Breast cancer is a heterogeneous disease from the histological and molecular expression point of view, and this heterogeneity determines cancer aggressiveness. Store-operated Ca2+ entry (SOCE), a major mechanism for Ca2+ entry in non-excitable cells, is significantly remodeled in cancer cells and plays an important role in the development and support of different cancer hallmarks. The store-operated CRAC (Ca2+ release-activated Ca2+) channels are predominantly comprised of Orai1 but the participation of Orai2 and Orai3 subunits has been reported to modulate the magnitude of Ca2+ responses. Here we provide evidence for a heterogeneous expression of Orai2 among different breast cancer cell lines. In the HER2 and triple negative breast cancer cell lines SKBR3 and BT20, respectively, where the expression of Orai2 was greater, Orai2 modulates the magnitude of SOCE and sustain Ca2+ oscillations in response to carbachol. Interestingly, in these cells Orai2 modulates the activation of NFAT1 and NFAT4 in response to high and low agonist concentrations. Finally, we have found that, in cells with high Orai2 expression, Orai2 knockdown leads to cell cycle arrest at the G0-G1 phase and decreases apoptosis resistance upon cisplatin treatment. Altogether, these findings indicate that, in breast cancer cells with a high Orai2 expression, Orai2 plays a relevant functional role in agonist-evoked Ca2+ signals, cell proliferation and apoptosis resistance.
Collapse
|
4
|
Xu F, Wang Y, Gao H, Zhang X, Hu Y, Han T, Shen B, Zhang L, Wu Q. X-Ray Causes mRNA Transcripts Change to Enhance Orai2-Mediated Ca 2+ Influx in Rat Brain Microvascular Endothelial Cells. Front Mol Biosci 2021; 8:646730. [PMID: 34595206 PMCID: PMC8477418 DOI: 10.3389/fmolb.2021.646730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/05/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Radiation-induced brain injury is a serious and treatment-limiting complication of brain radiation therapy. Although endothelial cell dysfunction plays a critical role in the development of this pathogenesis, the underlying molecular mechanisms remain elusive. Methods: Primary cultured rat brain microvascular endothelial cells (BMECs) were divided into five groups without or with exposure of x-rays delivered at 5 Gy or 20 Gy. For the irradiated groups, cells were continued to cultivate for 12 or 24 h after being irradiated. Then the mRNA libraries of each group were established and applied for next-generation sequencing. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted to analyze the sequencing results. Quantitative polymerase chain reaction, western blotting, cck8 assay and intracellular calcium concentration assays were conducted to analyze the role of Orai2-associated SOCE in x-ray induced cellular injury. Results: In total, 3,005 transcripts in all the four x-ray-exposed groups of BMECs showed expression level changes compared with controls. With the dose of x-ray augment and the following cultured time extension, the numbers of differentially expressed genes (DEGs) increased significantly in BMECs. Venn diagrams identified 40 DEGs common to all four exposure groups. Functional pathway enrichment analyses indicated that those 40 DEGs were enriched in the calcium signaling pathway. Among those 40 DEGs, mRNA and protein expression levels of Orai2 were significantly upregulated for 24 h. Similarly, calcium influx via store-operated calcium entry, which is modulated by Orai2, was also significantly increased for 24 h in x-ray-exposed BMECs. Moreover, the change in SOCE was suppressed by btp-2, which is a non-selective inhibitor of Orai. Additionally, x-ray exposure induced a significant decrease of proliferation in BMECs in the dose- and time-dependent manner. Conclusion: These findings provide evidence for molecular mechanisms underlying BMECs dysfunction in development of radiation-induced brain injury and suggest new approaches for therapeutic targets.
Collapse
Affiliation(s)
- Fangfang Xu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yang Wang
- Department of Otolaryngology-Head and Neck Surgery, Lu'an People's Hospital, Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China.,School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Huiwen Gao
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Xinchen Zhang
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yu Hu
- Department of Otolaryngology-Head and Neck Surgery, Lu'an People's Hospital, Lu'an Affiliated Hospital of Anhui Medical University, Lu'an, China
| | - Tingting Han
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Bing Shen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Lesha Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qibing Wu
- Department of Radiotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| |
Collapse
|
5
|
Abstract
Calcium is a major intracellular signaling messenger in innate immune cells. Similar to other immune cell subsets, the majority of calcium entry into innate immune cells is induced by cell surface receptors that stimulate store-operated calcium entry through calcium-release activated calcium (CRAC) channels. Since the molecular description of the STIM family of calcium sensors and the ORAI family of CRAC channel proteins, the majority of studies support a dominant role for these proteins in calcium signaling in innate cells. In reviewing the literature on CRAC channel function in innate cells, several general themes emerge. All innate cells express multiple members of the STIM and ORAI family members, however the ratio and relative contribution of individual isoforms changes depending on the cell type and activation state of the cell. It is evident that study of functional roles for STIM molecules is clearly ahead of studies of specific ORAI family members in all innate cell types, and that studies of CRAC channels in innate cells are not nearly as advanced as studies in lymphocytes. However, taken together, evidence from both STIM calcium sensors and ORAI channels in innate cells indicates that deficiency of STIM and ORAI proteins tends not to affect the development of any innate cell lineage, but certainly affects their function, in particular activation of the neutrophil oxidase and mast cell activation via IgE receptors. Furthermore, there are clearly hints that therapeutic targeting of CRAC channels in innate cells offers a new approach to various inflammatory and allergic diseases.
Collapse
Affiliation(s)
- Regina A Clemens
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States.
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, CA, United States
| |
Collapse
|
6
|
Diez-Bello R, Jardin I, Salido GM, Rosado JA. Orai1 and Orai2 mediate store-operated calcium entry that regulates HL60 cell migration and FAK phosphorylation. Biochim Biophys Acta Mol Cell Res 2017; 1864:1064-70. [PMID: 27865925 DOI: 10.1016/j.bbamcr.2016.11.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/07/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a major mechanism for the regulation of intracellular Ca2+ homeostasis and cellular function. Emerging evidence has revealed that altered expression and function of the molecular determinants of SOCE play a critical role in the development or maintenance of several cancer hallmarks, including enhanced proliferation and migration. Here we show that, in the acute myeloid leukemia cell line HL60, Orai2 is highly expressed at the transcript level, followed by the expression of Orai1. Using fluorescence Ca2+ imaging we found that Orai2 silencing significantly attenuated thapsigargin-induced SOCE, as well as knockdown of Orai1, while silencing the expression of both channels almost completely reduced SOCE, thus suggesting that SOCE in these cells is strongly dependent on Orai1 and Orai2. On the other hand, the expression of TRPC1, TRPC3 and TRPC6 is almost absent at the transcript and protein level. Bromodeoxyuridine cell proliferation assay revealed that Orai1 and Orai2 expression silencing significantly reduced HL60 cell proliferation. Furthermore, knockdown of Orai1 and Orai2 significantly attenuated the ability of HL60 to migrate in vitro as determined by transwell migration assay, probably due to the impairment of FAK tyrosine phosphorylation. These findings provide evidence for a role for Orai1 and Orai2, in SOCE and migration in the human HL60 promyeloblastic cell line. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
Collapse
|
7
|
Hoth M. CRAC channels, calcium, and cancer in light of the driver and passenger concept. Biochim Biophys Acta 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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
Affiliation(s)
- Markus Hoth
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Building 48, Saarland University, D-66421 Homburg, Germany.
| |
Collapse
|
8
|
Moccia F, Zuccolo E, Soda T, Tanzi F, Guerra G, Mapelli L, Lodola F, D'Angelo E. Stim and Orai proteins in neuronal Ca(2+) signaling and excitability. Front Cell Neurosci 2015; 9:153. [PMID: 25964739 PMCID: PMC4408853 DOI: 10.3389/fncel.2015.00153] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/03/2015] [Indexed: 02/01/2023] Open
Abstract
Stim1 and Orai1 are ubiquitous proteins that have long been known to mediate Ca2+ release-activated Ca2+ (CRAC) current (ICRAC) and store-operated Ca2+ entry (SOCE) only in non-excitable cells. SOCE is activated following the depletion of the endogenous Ca2+ stores, which are mainly located within the endoplasmic reticulum (ER), to replete the intracellular Ca2+ reservoir and engage specific Ca2+-dependent processes, such as proliferation, migration, cytoskeletal remodeling, and gene expression. Their paralogs, Stim2, Orai2 and Orai3, support SOCE in heterologous expression systems, but their physiological role is still obscure. Ca2+ inflow in neurons has long been exclusively ascribed to voltage-operated and receptor-operated channels. Nevertheless, recent work has unveiled that Stim1–2 and Orai1-2, but not Orai3, proteins are also expressed and mediate SOCE in neurons. Herein, we survey current knowledge about the neuronal distribution of Stim and Orai proteins in rodent and human brains; we further discuss that Orai2 is the main pore-forming subunit of CRAC channels in central neurons, in which it may be activated by either Stim1 or Stim2 depending on species, brain region and physiological stimuli. We examine the functions regulated by SOCE in neurons, where this pathway is activated under resting conditions to refill the ER, control spinogenesis and regulate gene transcription. Besides, we highlighted the possibility that SOCE also controls neuronal excitation and regulate synaptic plasticity. Finally, we evaluate the involvement of Stim and Orai proteins in severe neurodegenerative and neurological disorders, such as Alzheimer’s disease and epilepsy.
Collapse
Affiliation(s)
- Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia Pavia, Italy
| | - Estella Zuccolo
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia Pavia, Italy
| | - Teresa Soda
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy
| | - Franco Tanzi
- Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia Pavia, Italy
| | - Germano Guerra
- Department of Medicine and Health Sciences, University of Molise Campobasso, Italy
| | - Lisa Mapelli
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Museo Storico della Fisica e Centro di Studi e Ricerche Enrico Fermi Roma, Italy
| | - Francesco Lodola
- Laboratory of Molecular Cardiology, IRCCS Fondazione Salvatore Maugeri Pavia, Italy
| | - Egidio D'Angelo
- Neurophysiology Unit, Department of Brain and Behavioral Sciences, University of Pavia Pavia, Italy ; Brain Connectivity Center, C. Mondino National Neurological Institute, Fondazione IRCCS Policlinico San Matteo Pavia Pavia, Italy
| |
Collapse
|
9
|
Inayama M, Suzuki Y, Yamada S, Kurita T, Yamamura H, Ohya S, Giles WR, Imaizumi Y. Orai1- Orai2 complex is involved in store-operated calcium entry in chondrocyte cell lines. Cell Calcium 2015; 57:337-47. [PMID: 25769459 DOI: 10.1016/j.ceca.2015.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 02/01/2015] [Accepted: 02/11/2015] [Indexed: 12/18/2022]
Abstract
Ca(2+) influx via store-operated Ca(2+) entry (SOCE) plays critical roles in many essential cellular functions. The Ca(2+) release-activated Ca(2+) (CRAC) channel complex, consisting of Orai and STIM, is one of the major components of store-operated Ca(2+) (SOC) channels. Our previous study demonstrated that histamine can cause sustained Ca(2+) entry through SOC channels in OUMS-27 cells derived from human chondrosarcoma. This SOCE was increased by low- and decreased by high-concentrations of 2-aminoethoxydiphenyl borate. Quantitative reverse transcription PCR and Western blot analyses revealed abundant expressions of Orai1, Orai2 and STIM1. Introduction of dominant negative mutant of Orai1, or siOrai1 knockdown significantly attenuated SOCE. Following histamine application, single molecule imaging using total internal reflection fluorescence (TIRF) microscopy demonstrated punctate Orai1-STIM1 complex formation in plasma membrane. In contrast, knockdown or over-expression of Orai2 resulted in an increase or a decrease in SOCE, respectively. Finally, TIRF imaging revealed direct coupling between Orai1 and Orai2, and suggested that Orai2 reduces Orai1 function by formation of a hetero-tetramer. These results provide substantial evidence that Orai1, Orai2 and STIM1 form functional CRAC channels in OUMS-27 cells and that these complexes are responsible for sustained Ca(2+) entry in response to agonist stimulation.
Collapse
Affiliation(s)
- Munenori Inayama
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yoshiaki Suzuki
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Satoshi Yamada
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Takashi Kurita
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Hisao Yamamura
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Susumu Ohya
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan; Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Wayne R Giles
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Yuji Imaizumi
- Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
| |
Collapse
|
10
|
Hendron E, Wang X, Zhou Y, Cai X, Goto JI, Mikoshiba K, Baba Y, Kurosaki T, Wang Y, Gill DL. Potent functional uncoupling between STIM1 and Orai1 by dimeric 2-aminodiphenyl borinate analogs. Cell Calcium 2014; 56:482-92. [PMID: 25459299 DOI: 10.1016/j.ceca.2014.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 12/21/2022]
Abstract
The coupling of ER Ca(2+)-sensing STIM proteins and PM Orai Ca(2+) entry channels generates "store-operated" Ca(2+) signals crucial in controlling responses in many cell types. The dimeric derivative of 2-aminoethoxydiphenyl borinate (2-APB), DPB162-AE, blocks functional coupling between STIM1 and Orai1 with an IC50 (200 nM) 100-fold lower than 2-APB. Unlike 2-APB, DPB162-AE does not affect L-type or TRPC channels or Ca(2+) pumps at maximal STIM1-Orai1 blocking levels. DPB162-AE blocks STIM1-induced Orai1 or Orai2, but does not block Orai3 or STIM2-mediated effects. We narrowed the DPB162-AE site of action to the STIM-Orai activating region (SOAR) of STIM1. DPB162-AE does not prevent the SOAR-Orai1 interaction but potently blocks SOAR-mediated Orai1 channel activation, yet its action is not as an Orai1 channel pore blocker. Using the SOAR-F394H mutant which prevents both physical and functional coupling to Orai1, we reveal DPB162-AE rapidly restores SOAR-Orai binding but only slowly restores Orai1 channel-mediated Ca(2+) entry. With the same SOAR mutant, 2-APB induces rapid physical and functional coupling to Orai1, but channel activation is transient. We infer that the actions of both 2-APB and DPB162-AE are directed toward the STIM1-Orai1 coupling interface. Compared to 2-APB, DPB162-AE is a much more potent and specific STIM1/Orai1 functional uncoupler. DPB162-AE provides an important pharmacological tool and a useful mechanistic probe for the function and coupling between STIM1 and Orai1 channels.
Collapse
Affiliation(s)
- Eunan Hendron
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Xizhuo Wang
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States; Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Xiangyu Cai
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Jun-ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
| | - Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development College of Life Sciences, Beijing Normal University, Beijing 100875, PR China.
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States.
| |
Collapse
|
11
|
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.
Collapse
Affiliation(s)
- Markus Hoth
- Department of Biophysics, Saarland University, Homburg, Germany
| | | |
Collapse
|