1
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Fröhlich M, Söllner J, Derler I. Insights into the dynamics of the Ca2+ release-activated Ca2+ channel pore-forming complex Orai1. Biochem Soc Trans 2024; 52:747-760. [PMID: 38526208 DOI: 10.1042/bst20230815] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/26/2024]
Abstract
An important calcium (Ca2+) entry pathway into the cell is the Ca2+ release-activated Ca2+ (CRAC) channel, which controls a series of downstream signaling events such as gene transcription, secretion and proliferation. It is composed of a Ca2+ sensor in the endoplasmic reticulum (ER), the stromal interaction molecule (STIM), and the Ca2+ ion channel Orai in the plasma membrane (PM). Their activation is initiated by receptor-ligand binding at the PM, which triggers a signaling cascade within the cell that ultimately causes store depletion. The decrease in ER-luminal Ca2+ is sensed by STIM1, which undergoes structural rearrangements that lead to coupling with Orai1 and its activation. In this review, we highlight the current understanding of the Orai1 pore opening mechanism. In this context, we also point out the questions that remain unanswered and how these can be addressed by the currently emerging genetic code expansion (GCE) technology. GCE enables the incorporation of non-canonical amino acids with novel properties, such as light-sensitivity, and has the potential to provide novel insights into the structure/function relationship of CRAC channels at a single amino acid level in the living cell.
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Affiliation(s)
- Maximilian Fröhlich
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Julia Söllner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
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2
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Bacsa B, Hopl V, Derler I. Synthetic Biology Meets Ca 2+ Release-Activated Ca 2+ Channel-Dependent Immunomodulation. Cells 2024; 13:468. [PMID: 38534312 DOI: 10.3390/cells13060468] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/27/2024] [Accepted: 03/05/2024] [Indexed: 03/28/2024] Open
Abstract
Many essential biological processes are triggered by the proximity of molecules. Meanwhile, diverse approaches in synthetic biology, such as new biological parts or engineered cells, have opened up avenues to precisely control the proximity of molecules and eventually downstream signaling processes. This also applies to a main Ca2+ entry pathway into the cell, the so-called Ca2+ release-activated Ca2+ (CRAC) channel. CRAC channels are among other channels are essential in the immune response and are activated by receptor-ligand binding at the cell membrane. The latter initiates a signaling cascade within the cell, which finally triggers the coupling of the two key molecular components of the CRAC channel, namely the stromal interaction molecule, STIM, in the ER membrane and the plasma membrane Ca2+ ion channel, Orai. Ca2+ entry, established via STIM/Orai coupling, is essential for various immune cell functions, including cytokine release, proliferation, and cytotoxicity. In this review, we summarize the tools of synthetic biology that have been used so far to achieve precise control over the CRAC channel pathway and thus over downstream signaling events related to the immune response.
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Affiliation(s)
- Bernadett Bacsa
- Division of Medical Physics und Biophysics, Medical University of Graz, A-8010 Graz, Austria
| | - Valentina Hopl
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
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3
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Zhou Y, Jennette MR, Ma G, Kazzaz SA, Baraniak JH, Nwokonko RM, Groff ML, Velasquez-Reynel M, Huang Y, Wang Y, Gill DL. An apical Phe-His pair defines the Orai1-coupling site and its occlusion within STIM1. Nat Commun 2023; 14:6921. [PMID: 37903816 PMCID: PMC10616141 DOI: 10.1038/s41467-023-42254-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 01/20/2023] [Accepted: 10/04/2023] [Indexed: 11/01/2023] Open
Abstract
Ca2+ signal-generation through inter-membrane junctional coupling between endoplasmic reticulum (ER) STIM proteins and plasma membrane (PM) Orai channels, remains a vital but undefined mechanism. We identify two unusual overlapping Phe-His aromatic pairs within the STIM1 apical helix, one of which (F394-H398) mediates important control over Orai1-STIM1 coupling. In resting STIM1, this locus is deeply clamped within the folded STIM1-CC1 helices, likely near to the ER surface. The clamped environment in holo-STIM1 is critical-positive charge replacing Phe-394 constitutively unclamps STIM1, mimicking store-depletion, negative charge irreversibly locks the clamped-state. In store-activated, unclamped STIM1, Phe-394 mediates binding to the Orai1 channel, but His-398 is indispensable for transducing STIM1-binding into Orai1 channel-gating, and is spatially aligned with Phe-394 in the exposed Sα2 helical apex. Thus, the Phe-His locus traverses between ER and PM surfaces and is decisive in the two critical STIM1 functions-unclamping to activate STIM1, and conformational-coupling to gate the Orai1 channel.
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Affiliation(s)
- Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
| | - Michelle R Jennette
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Guolin Ma
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX, 77030, USA
| | - Sarah A Kazzaz
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Robert M Nwokonko
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Mallary L Groff
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Marcela Velasquez-Reynel
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - 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, USA.
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4
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Pathak T, Benson JC, Johnson MT, Xin P, Abdelnaby AE, Walter V, Koltun WA, Yochum GS, Hempel N, Trebak M. Loss of STIM2 in colorectal cancer drives growth and metastasis through metabolic reprogramming and PERK-ATF4 endoplasmic reticulum stress pathway. bioRxiv 2023:2023.10.02.560521. [PMID: 37873177 PMCID: PMC10592933 DOI: 10.1101/2023.10.02.560521] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The endoplasmic reticulum (ER) stores large amounts of calcium (Ca2+), and the controlled release of ER Ca2+ regulates a myriad of cellular functions. Although altered ER Ca2+ homeostasis is known to induce ER stress, the mechanisms by which ER Ca2+ imbalance activate ER stress pathways are poorly understood. Stromal-interacting molecules STIM1 and STIM2 are two structurally homologous ER-resident Ca2+ sensors that synergistically regulate Ca2+ influx into the cytosol through Orai Ca2+ channels for subsequent signaling to transcription and ER Ca2+ refilling. Here, we demonstrate that reduced STIM2, but not STIM1, in colorectal cancer (CRC) is associated with poor patient prognosis. Loss of STIM2 causes SERCA2-dependent increase in ER Ca2+, increased protein translation and transcriptional and metabolic rewiring supporting increased tumor size, invasion, and metastasis. Mechanistically, STIM2 loss activates cMyc and the PERK/ATF4 branch of ER stress in an Orai-independent manner. Therefore, STIM2 and PERK/ATF4 could be exploited for prognosis or in targeted therapies to inhibit CRC tumor growth and metastasis.
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Affiliation(s)
- Trayambak Pathak
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - J. Cory Benson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- UPMC Hillman Cancer Center. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Martin T. Johnson
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Ping Xin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Ahmed Emam Abdelnaby
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Vonn Walter
- Department of Public Health Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States
- Penn State Cancer Institute. The Pennsylvania State University College of Medicine, Hershey, United States
| | - Walter A. Koltun
- Department of Surgery, Division of Colon and Rectal Surgery, The Pennsylvania State University College of Medicine, Hershey, United States
| | - Gregory S. Yochum
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, United States
- Department of Surgery, Division of Colon and Rectal Surgery, The Pennsylvania State University College of Medicine, Hershey, United States
| | - Nadine Hempel
- UPMC Hillman Cancer Center. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Mohamed Trebak
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
- UPMC Hillman Cancer Center. University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
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5
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Silvestri R, Nicolì V, Gangadharannambiar P, Crea F, Bootman MD. Calcium signalling pathways in prostate cancer initiation and progression. Nat Rev Urol 2023; 20:524-543. [PMID: 36964408 DOI: 10.1038/s41585-023-00738-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2023] [Indexed: 03/26/2023]
Abstract
Cancer cells proliferate, differentiate and migrate by repurposing physiological signalling mechanisms. In particular, altered calcium signalling is emerging as one of the most widespread adaptations in cancer cells. Remodelling of calcium signalling promotes the development of several malignancies, including prostate cancer. Gene expression data from in vitro, in vivo and bioinformatics studies using patient samples and xenografts have shown considerable changes in the expression of various components of the calcium signalling toolkit during the development of prostate cancer. Moreover, preclinical and clinical evidence suggests that altered calcium signalling is a crucial component of the molecular re-programming that drives prostate cancer progression. Evidence points to calcium signalling re-modelling, commonly involving crosstalk between calcium and other cellular signalling pathways, underpinning the onset and temporal progression of this disease. Discrete alterations in calcium signalling have been implicated in hormone-sensitive, castration-resistant and aggressive variant forms of prostate cancer. Hence, modulation of calcium signals and downstream effector molecules is a plausible therapeutic strategy for both early and late stages of prostate cancer. Based on this premise, clinical trials have been undertaken to establish the feasibility of targeting calcium signalling specifically for prostate cancer.
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Affiliation(s)
| | - Vanessa Nicolì
- Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | | | - Francesco Crea
- Cancer Research Group, School of Life Health and Chemical Sciences, The Open University, Milton Keynes, UK
| | - Martin D Bootman
- Cancer Research Group, School of Life Health and Chemical Sciences, The Open University, Milton Keynes, UK.
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6
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Liang C, Wu F. Reconstitution of Calcium Channel Protein Orai3 into Liposomes for Functional Studies. Biochemistry (Mosc) 2023; 88:1296-1303. [PMID: 37770396 DOI: 10.1134/s0006297923090092] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/14/2023] [Accepted: 08/02/2023] [Indexed: 09/30/2023]
Abstract
Store-operated calcium entry (SOCE) is the main mechanism for the Ca2+ influx in non-excitable cells. The two major components of SOCE are stromal interaction molecule 1 (STIM1) in the endoplasmic reticulum and Ca2+ release-activated Ca2+ channel (CRAC) Orai on the plasma membrane. SOCE requires interaction between STIM1 and Orai. Mammals have three Orai homologs: Orai1, Orai2, and Orai3. Although Orai1 has been widely studied and proven to essential for numerous cellular processes, Orai3 has also attracted a significant attention recently. The gating and activation mechanisms of Orai3 have yet to be fully elucidated. Here, we expressed, purified, and reconstituted Orai3 protein into liposomes and investigated its orientation and oligomeric state in the resulting proteoliposomes. STIM1 interacted with the Orai3-containing proteoliposomes and mediated calcium release from the them, suggesting that the Orai3 channel was functional and that recombinant STIM1 could directly open the Orai3 channel in vitro. The developed in vitro calcium release system could be used to study the structure, function, and pharmacology of Orai3 channel.
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Affiliation(s)
- Chuangxuan Liang
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.
| | - Fuyun Wu
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, China.
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
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7
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Yu T, Li X, Luo Q, Liu H, Jin J, Li S, He J. S417 in the CC3 region of STIM1 is critical for STIM1-Orai1 binding and CRAC channel activation. Life Sci Alliance 2023; 6:e202201623. [PMID: 36690443 PMCID: PMC9873985 DOI: 10.26508/lsa.202201623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a universal Ca2+ influx pathway that is important for the function of many cell types. SOCE is controlled by the interaction of the ER Ca2+ sensor STIM1 with the plasma membrane Ca2+ channel Orai1. S417 is located in the third coiled-coil (CC3) domain of the C-terminus of STIM1. We found that single-point mutation of this residue (S417G) abolished STIM1 C-terminus interactions with Orai1. Mutation of S417 also abolished CAD-Orai1 binding and Orai1 channel activation, eliminated STIM1 puncta formation, and co-localization with Orai1 and SOCE. 2-APB was found to restore the binding of the STIM1 C-terminus mutant (S417G) to Orai1 and dose-dependently activate Orai1 channel. Both CBD and NBD of Orai1 are required for 2-APB-induced coupling between the Orai1 and STIM1 C-terminus mutant (S417G) and CRAC channel activation. We also demonstrated that 2-APB led to delayed activation of Orai1-K85E channel, although Orai1-K85E obviously impairs 2-APB-induced STIM1 C-terminus mutant (S417G)-Orai1 coupling. Our results suggest S417 in the CC3 domain of STIM1 is essential for STIM1-Orai1 binding and CRAC channel activation.
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Affiliation(s)
- Tao Yu
- Department of Clinical Laboratory, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Li
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qianqian Luo
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huajing Liu
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Jin
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shengjie Li
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun He
- Division of Histology and Embryology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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8
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Yeung PSW, Yamashita M, Prakriya M. A pathogenic human Orai1 mutation unmasks STIM1-independent rapid inactivation of Orai1 channels. eLife 2023; 12:82281. [PMID: 36806330 PMCID: PMC9991058 DOI: 10.7554/elife.82281] [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: 07/29/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Ca2+ release-activated Ca2+ (CRAC) channels are activated by direct physical interactions between Orai1, the channel protein, and STIM1, the endoplasmic reticulum Ca2+ sensor. A hallmark of CRAC channels is fast Ca2+-dependent inactivation (CDI) which provides negative feedback to limit Ca2+ entry through CRAC channels. Although STIM1 is thought to be essential for CDI, its molecular mechanism remains largely unknown. Here, we examined a poorly understood gain-of-function (GOF) human Orai1 disease mutation, L138F, that causes tubular aggregate myopathy. Through pairwise mutational analysis, we determine that large amino acid substitutions at either L138 or the neighboring T92 locus located on the pore helix evoke highly Ca2+-selective currents in the absence of STIM1. We find that the GOF phenotype of the L138 pathogenic mutation arises due to steric clash between L138 and T92. Surprisingly, strongly activating L138 and T92 mutations showed CDI in the absence of STIM1, contradicting prevailing views that STIM1 is required for CDI. CDI of constitutively open T92W and L138F mutants showed enhanced intracellular Ca2+ sensitivity, which was normalized by re-adding STIM1 to the cells. Truncation of the Orai1 C-terminus reduced T92W CDI, indicating a key role for the Orai1 C-terminus for CDI. Overall, these results identify the molecular basis of a disease phenotype with broad implications for activation and inactivation of Orai1 channels.
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Affiliation(s)
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern UniversityChicagoUnited States
| | - Murali Prakriya
- Department of Pharmacology, Northwestern UniversityChicagoUnited States
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9
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Protasi F, Girolami B, Roccabianca S, Rossi D. Store-operated calcium entry: From physiology to tubular aggregate myopathy. Curr Opin Pharmacol 2023; 68:102347. [PMID: 36608411 DOI: 10.1016/j.coph.2022.102347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/30/2022] [Accepted: 12/04/2022] [Indexed: 01/06/2023]
Abstract
Store-Operated Ca2+ entry (SOCE) is recognized as a key mechanism in muscle physiology necessary to refill intracellular Ca2+ stores during sustained muscle activity. For many years the cell structures expected to mediate SOCE in skeletal muscle fibres remained unknown. Recently, the identification of Ca2+ Entry Units (CEUs) in exercised muscle fibres opened new insights into the role of extracellular Ca2+ in muscle contraction and, more generally, in intracellular Ca2+ homeostasis. Accordingly, intracellular Ca2+ unbalance due to alterations in SOCE strictly correlates with muscle disfunction and disease. Mutations in proteins involved in SOCE (STIM1, ORAI1, and CASQ1) have been linked to tubular aggregate myopathy (TAM), a disease that causes muscle weakness and myalgia and is characterized by a typical accumulation of highly ordered and packed membrane tubules originated from the sarcoplasmic reticulum (SR). Achieving a full understanding of the molecular pathways activated by alterations in Ca2+ entry mechanisms is a necessary step to design effective therapies for human SOCE-related disorders.
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Affiliation(s)
- Feliciano Protasi
- CAST, Center for Advanced Studies and Technology; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy; DMSI, Department of Medicine and Aging Sciences; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy
| | - Barbara Girolami
- CAST, Center for Advanced Studies and Technology; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy; DMSI, Department of Medicine and Aging Sciences; University G. d'Annunzio of Chieti-Pescara, I-66100, Italy
| | - Sara Roccabianca
- DMMS, Department of Molecular and Developmental Medicine; University of Siena, I-53100, Siena Italy
| | - Daniela Rossi
- DMMS, Department of Molecular and Developmental Medicine; University of Siena, I-53100, Siena Italy.
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10
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Hallett MB. Localisation of Intracellular Signals and Responses during Phagocytosis. Int J Mol Sci 2023; 24. [PMID: 36769146 DOI: 10.3390/ijms24032825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 02/05/2023] Open
Abstract
Phagocytosis is one of the most polarised of all cellular activities. Both the stimulus (the target for phagocytosis) and the response (its internalisation) are focussed at just one part of the cell. At the locus, and this locus alone, pseudopodia form a phagocytic cup around the particle, the cytoskeleton is rearranged, the plasma membrane is reorganised, and a new internal organelle, the phagosome, is formed. The effect of signals from the stimulus must, thus, both be complex and yet be restricted in space and time to enable an effective focussed response. While many aspects of phagocytosis are being uncovered, the mechanism for the restriction of signalling or the effects of signalling remains obscure. In this review, the details of the problem of restricting chemical intracellular signalling are presented, with a focus on diffusion into the cytosol and of signalling lipids along the plasma membrane. The possible ways in which simple diffusion is overcome so that the restriction of signalling and effective phagocytosis can be achieved are discussed in the light of recent advances in imaging, biophysics, and cell biochemistry which together are providing new insights into this area.
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11
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Jaślan D, Ferro IF, Kudrina V, Yuan Y, Patel S, Grimm C. PI(3,5)P 2 and NAADP: Team players or lone warriors? - New insights into TPC activation modes. Cell Calcium 2023; 109:102675. [PMID: 36525777 DOI: 10.1016/j.ceca.2022.102675] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 10/19/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022]
Abstract
NAADP (nicotinic acid adenine dinucleotide phosphate) is a second messenger, releasing Ca2+ from acidic calcium stores such as endosomes and lysosomes. PI(3,5)P2 (phosphatidylinositol 3,5-bisphosphate) is a phospho-inositide, residing on endolysosomal membranes and likewise releasing Ca2+ from endosomes and lysosomes. Both compounds have been shown to activate endolysosomal two-pore channels (TPCs) in mammalian cells. However, their effects on ion permeability as demonstrated specifically for TPC2 differ. While PI(3,5)P2 elicits predominantly Na+-selective currents, NAADP increases the Ca2+ permeability of the channel. What happens when both compounds are applied simultaneously was unclear until recently.
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Affiliation(s)
- Dawid Jaślan
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Irene Flavia Ferro
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Veronika Kudrina
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Yu Yuan
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilians-University, Munich, Germany.
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12
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Tiffner A, Hopl V, Derler I. CRAC and SK Channels: Their Molecular Mechanisms Associated with Cancer Cell Development. Cancers (Basel) 2022; 15:cancers15010101. [PMID: 36612099 PMCID: PMC9817886 DOI: 10.3390/cancers15010101] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
Cancer represents a major health burden worldwide. Several molecular targets have been discovered alongside treatments with positive clinical outcomes. However, the reoccurrence of cancer due to therapy resistance remains the primary cause of mortality. Endeavors in pinpointing new markers as molecular targets in cancer therapy are highly desired. The significance of the co-regulation of Ca2+-permeating and Ca2+-regulated ion channels in cancer cell development, proliferation, and migration make them promising molecular targets in cancer therapy. In particular, the co-regulation of the Orai1 and SK3 channels has been well-studied in breast and colon cancer cells, where it finally leads to an invasion-metastasis cascade. Nevertheless, many questions remain unanswered, such as which key molecular components determine and regulate their interplay. To provide a solid foundation for a better understanding of this ion channel co-regulation in cancer, we first shed light on the physiological role of Ca2+ and how this ion is linked to carcinogenesis. Then, we highlight the structure/function relationship of Orai1 and SK3, both individually and in concert, their role in the development of different types of cancer, and aspects that are not yet known in this context.
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13
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Gu C, Zhang W, Yang E, Gu C, Zhang Z, Ke J, Wang X, Wu S, Li S, Wu F. Blockage of Orai1-Nucleolin interaction meditated calcium influx attenuates breast cancer cells growth. Oncogenesis 2022; 11:55. [PMID: 36109490 PMCID: PMC9478099 DOI: 10.1038/s41389-022-00429-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractAs an important second messenger, calcium (Ca2+) regulates a wide variety of physiological processes. Disturbance of intracellular calcium homeostasis implicated in the occurrence of multiple types of diseases. Orai1 is the major player in mediating store-operated calcium entry (SOCE) and regulates calcium homeostasis in non-excitable cells. Over-expression and activation of Orai1 have been reported in breast cancer. However, its molecular mechanisms are still not very clear. Here, we demonstrated that Nucleolin (NCL) was a novel interacting partner of Orai1. NCL is a multifunctional nucleocytoplasmic protein and is upregulated in human breast tumors. The binding of C-termini of NCL (NCL-CT) to N-termini of Orai1 (Orai1-NT) is critical for mediating calcium influx and proliferation of breast cancer cells. Blocking the NCL-Orai1 interaction by synthesized Orai1 peptide can effectively reduce the intracellular calcium influx and suppress the proliferation of breast cancer cells in vitro and in vivo. Our findings reveal a novel activation mechanism of Orai1 via direct interaction with NCL, which may lead to calcium homeostasis imbalance and promote the proliferation of breast cancer cells. Blocking NCL-Orai1 interaction might be an effective treatment of breast cancer.
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Shrestha N, Hye-Ryong Shim A, Maneshi MM, See-Wai Yeung P, Yamashita M, Prakriya M. Mapping interactions between the CRAC activation domain and CC1 regulating the activity of the ER Ca 2+ sensor STIM1. J Biol Chem 2022; 298:102157. [PMID: 35724962 PMCID: PMC9304783 DOI: 10.1016/j.jbc.2022.102157] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/04/2022] [Accepted: 06/06/2022] [Indexed: 11/25/2022] Open
Abstract
Stromal interaction molecule 1 (STIM1) is a widely expressed protein that functions as the endoplasmic reticulum (ER) Ca2+ sensor and activator of Orai1 channels. In resting cells with replete Ca2+ stores, an inhibitory clamp formed by the coiled-coil 1 (CC1) domain interacting with the CRAC-activation domain (CAD) of STIM1 helps keep STIM1 in a quiescent state. Following depletion of ER Ca2+ stores, the brake is released, allowing CAD to extend away from the ER membrane and enabling it to activate Orai1 channels. However, the molecular determinants of CC1-CAD interactions that enforce the inhibitory clamp are incompletely understood. Here, we performed Ala mutagenesis in conjunction with live-cell FRET analysis to examine residues in CC1 and CAD that regulate the inhibitory clamp. Our results indicate that in addition to previously identified hotspots in CC1⍺1 and CC3, several hydrophobic residues in CC2 and the apex region of CAD are critical for CC1-CAD interactions. Mutations in these residues loosen the CC1-CAD inhibitory clamp to release CAD from CC1 in cells with replete Ca2+ stores. By contrast, altering the hydrophobic residues L265 and L273 strengthens the clamp to prevent STIM1 activation. Inclusion of the inactivation domain of STIM1 helps stabilize CC1-CAD interaction in several mutants to prevent spontaneous STIM1 activation. In addition, R426C, a human disease-linked mutation in CC3, affects the clamp but also impairs Orai1 binding to inhibit CRAC channel activation. These results identify the CC2, apex, and inactivation domain regions of STIM1 as important determinants of STIM1 activation.
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Affiliation(s)
- Nisha Shrestha
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ann Hye-Ryong Shim
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mohammad Mehdi Maneshi
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Priscilla See-Wai Yeung
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
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15
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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.
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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.
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16
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Souza Bomfim GH, Niemeyer BA, Lacruz RS, Lis A. On the Connections between TRPM Channels and SOCE. Cells 2022; 11:1190. [PMID: 35406753 PMCID: PMC8997886 DOI: 10.3390/cells11071190] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/23/2022] [Accepted: 03/30/2022] [Indexed: 12/02/2022] Open
Abstract
Plasma membrane protein channels provide a passageway for ions to access the intracellular milieu. Rapid entry of calcium ions into cells is controlled mostly by ion channels, while Ca2+-ATPases and Ca2+ exchangers ensure that cytosolic Ca2+ levels ([Ca2+]cyt) are maintained at low (~100 nM) concentrations. Some channels, such as the Ca2+-release-activated Ca2+ (CRAC) channels and voltage-dependent Ca2+ channels (CACNAs), are highly Ca2+-selective, while others, including the Transient Receptor Potential Melastatin (TRPM) family, have broader selectivity and are mostly permeable to monovalent and divalent cations. Activation of CRAC channels involves the coupling between ORAI1-3 channels with the endoplasmic reticulum (ER) located Ca2+ store sensor, Stromal Interaction Molecules 1-2 (STIM1/2), a pathway also termed store-operated Ca2+ entry (SOCE). The TRPM family is formed by 8 members (TRPM1-8) permeable to Mg2+, Ca2+, Zn2+ and Na+ cations, and is activated by multiple stimuli. Recent studies indicated that SOCE and TRPM structure-function are interlinked in some instances, although the molecular details of this interaction are only emerging. Here we review the role of TRPM and SOCE in Ca2+ handling and highlight the available evidence for this interaction.
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Affiliation(s)
- Guilherme H. Souza Bomfim
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA;
| | - Barbara A. Niemeyer
- Department of Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, 66421 Homburg, Germany;
| | - Rodrigo S. Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY 10010, USA;
| | - Annette Lis
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, 66421 Homburg, Germany
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17
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Cao L, Yang K, Yuan W, Zhou S, Zhao R, Qiu S. Melatonin Mediates Osteoblast Proliferation Through the STIM1/ORAI1 Pathway. Front Pharmacol 2022; 13:851663. [PMID: 35392575 PMCID: PMC8980543 DOI: 10.3389/fphar.2022.851663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 01/10/2022] [Accepted: 03/08/2022] [Indexed: 01/09/2023] Open
Abstract
Based on the positive correlation between bone mineral density and melatonin levels in blood, this study confirmed that melatonin supplementation prevents postmenopausal osteoporosis. We further confirmed that melatonin promotes an increase in intracellular calcium concentrations through the STIM1/ORAI1 pathway, thereby inducing the proliferation of osteoblasts. Introduction: Osteoporosis (OP) is a progressive, systemic bone disease that is one of the main causes of disability and death in elderly female patients. As an amine hormone produced by the human pineal gland, melatonin plays an important role in regulating bone metabolism. This study intends to investigate the relationship between melatonin levels in human blood and bone density and to suggest the efficacy of melatonin in treating osteoporosis by performing in vivo and in vitro experiments. Methods: We used liquid chromatography-tandem mass spectrometry to determine the serum melatonin levels in postmenopausal women with osteoporosis and young women with a normal bone mass. The bone density, BV/TV, Tb.Th, Tb.Sp and other indicators of postmenopausal osteoporosis and mice with a normal bone mass were detected by measuring bone density and micro-CT. The intracellular calcium ion concentration was detected using fluorescence microscopy and a full-wavelength multifunctional microplate reader, and the expression of SOCE-related genes and STIM1/ORAI1 proteins was detected using PCR and WB. Results: This study confirmed that bone density positively correlates with the melatonin level in human blood. In the animal model, melatonin supplementation reverses postmenopausal osteoporosis. We explored the internal mechanism of melatonin treatment of osteoporosis. Melatonin promotes an increase in intracellular calcium ion concentrations through the STIM1/ORAI1 pathway to induce osteoblast proliferation. Conclusions: This study provides an important theoretical basis for the clinical application of melatonin in patients with osteoporosis and helps to optimize the diagnosis and treatment of postmenopausal osteoporosis.
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Affiliation(s)
- Lili Cao
- Department of Medical Oncology, First Hospital of China Medical University, Shenyang, China
| | - Keda Yang
- Department of Orthopedics, First Hospital of China Medical University, Shenyang, China
| | - Wei Yuan
- Department of Orthopedics, First Hospital of China Medical University, Shenyang, China
| | - Siming Zhou
- Department of Orthopedics, First Hospital of China Medical University, Shenyang, China
| | - Rui Zhao
- Minimally Invasive Orthopedic Surgery Ward, Shenyang Orthopedic Hospital, Shenyang, China
| | - Shui Qiu
- Department of Orthopedics, First Hospital of China Medical University, Shenyang, China
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18
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Zhang N, Pan H, Liang X, Xie J, Han W. The roles of transmembrane family proteins in the regulation of store-operated Ca 2+ entry. Cell Mol Life Sci 2022; 79:118. [PMID: 35119538 DOI: 10.1007/s00018-021-04034-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 07/19/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a major pathway for calcium signaling, which regulates almost every biological process, involving cell proliferation, differentiation, movement and death. Stromal interaction molecule (STIM) and ORAI calcium release-activated calcium modulator (ORAI) are the two major proteins involved in SOCE. With the deepening of studies, more and more proteins are found to be able to regulate SOCE, among which the transmembrane (TMEM) family proteins are worth paying more attention. In addition, the ORAI proteins belong to the TMEM family themselves. As the name suggests, TMEM family is a type of proteins that spans biological membranes including plasma membrane and membrane of organelles. TMEM proteins are in a large family with more than 300 proteins that have been already identified, while the functional knowledge about the proteins is preliminary. In this review, we mainly summarized the TMEM proteins that are involved in SOCE, to better describe a picture of the interaction between STIM and ORAI proteins during SOCE and its downstream signaling pathways, as well as to provide an idea for the study of the TMEM family proteins.
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Affiliation(s)
- Ningxia Zhang
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Hongming Pan
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Xiaojing Liang
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jiansheng Xie
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China. .,Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
| | - Weidong Han
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
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19
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Chen YF, Shen MR. The Important Role of Ion Transport System in Cervical Cancer. Int J Mol Sci 2021; 23:333. [PMID: 35008759 DOI: 10.3390/ijms23010333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 12/12/2021] [Revised: 12/26/2021] [Accepted: 12/27/2021] [Indexed: 12/15/2022] Open
Abstract
Cervical cancer is a significant gynecological cancer and causes cancer-related deaths worldwide. Human papillomavirus (HPV) is implicated in the etiology of cervical malignancy. However, much evidence indicates that HPV infection is a necessary but not sufficient cause in cervical carcinogenesis. Therefore, the cellular pathophysiology of cervical cancer is worthy of study. This review summarizes the recent findings concerning the ion transport processes involved in cell volume regulation and intracellular Ca2+ homeostasis of epithelial cells and how these transport systems are themselves regulated by the tumor microenvironment. For cell volume regulation, we focused on the volume-sensitive Cl− channels and K+-Cl− cotransporter (KCC) family, important regulators for ionic and osmotic homeostasis of epithelial cells. Regarding intracellular Ca2+ homeostasis, the Ca2+ store sensor STIM molecules and plasma membrane Ca2+ channel Orai proteins, the predominant Ca2+ entry mechanism in epithelial cells, are discussed. Furthermore, we evaluate the potential of these membrane ion transport systems as diagnostic biomarkers and pharmacological interventions and highlight the challenges.
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20
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Knapp ML, Alansary D, Poth V, Förderer K, Sommer F, Zimmer D, Schwarz Y, Künzel N, Kless A, Machaca K, Helms V, Mühlhaus T, Schroda M, Lis A, Niemeyer BA. A longer isoform of Stim1 is a negative SOCE regulator but increases cAMP-modulated NFAT signaling. EMBO Rep 2021; 23:e53135. [PMID: 34942054 PMCID: PMC8892257 DOI: 10.15252/embr.202153135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 04/26/2021] [Revised: 11/23/2021] [Accepted: 12/07/2021] [Indexed: 11/23/2022] Open
Abstract
Alternative splicing is a potent modifier of protein function. Stromal interaction molecule 1 (Stim1) is the essential activator of store‐operated Ca2+ entry (SOCE) triggering activation of transcription factors. Here, we characterize Stim1A, a splice variant with an additional 31 amino acid domain inserted in frame within its cytosolic domain. Prominent expression of exon A is found in astrocytes, heart, kidney, and testes. Full‐length Stim1A functions as a dominant‐negative regulator of SOCE and ICRAC, facilitating sequence‐specific fast calcium‐dependent inactivation and destabilizing gating of Orai channels. Downregulation or absence of native Stim1A results in increased SOCE. Despite reducing SOCE, Stim1A leads to increased NFAT translocation. Differential proteomics revealed an interference of Stim1A with the cAMP‐SOCE crosstalk by altered modulation of phosphodiesterase 8 (PDE8), resulting in reduced cAMP degradation and increased PIP5K activity, facilitating NFAT activation. Our study uncovers a hitherto unknown mechanism regulating NFAT activation and indicates that cell‐type‐specific splicing of Stim1 is a potent means to regulate the NFAT signalosome and cAMP‐SOCE crosstalk.
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Affiliation(s)
- Mona L Knapp
- Molecular Biophysics, Saarland University, Homburg, Germany
| | - Dalia Alansary
- Molecular Biophysics, Saarland University, Homburg, Germany
| | - Vanessa Poth
- Molecular Biophysics, Saarland University, Homburg, Germany
| | | | - Frederik Sommer
- Molecular Biotechnology and Systems Biology, TU Kaiserslautern, Kaiserslautern, Germany
| | - David Zimmer
- Computational Systems Biology, TU Kaiserslautern, Kaiserslautern, Germany
| | - Yvonne Schwarz
- Molecular Neurophysiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, Homburg, Germany
| | - Nicolas Künzel
- Center for Bioinformatics, Saarland University, Saarbruecken, Germany
| | - Achim Kless
- Grünenthal Innovation, Drug Discovery Technologies, Grünenthal GmbH, Aachen, Germany
| | | | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Saarbruecken, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, TU Kaiserslautern, Kaiserslautern, Germany
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, TU Kaiserslautern, Kaiserslautern, Germany
| | - Annette Lis
- Biophysics, Saarland University, Homburg, Germany
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21
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Abstract
CRAC channel is ubiquitous and its importance in the regulation of the immune system is testified by the severe immunodeficiencies caused by its mutations. In this work we took advantage of the availability of open and closed structures of this channel to run for the first time simulations of the whole gating process reaching the relevant time-scale with an enhanced sampling technique, Targeted Molecular Dynamics. Our simulations highlighted a complex allosteric propagation of the conformational change from peripheral helices, where the activator STIM1 binds, to the central pore helices. In agreement with mutagenesis data, our simulations revealed the key role of residue H206 whose displacement creates an empty space behind the hydrophobic region of the pore, thus releasing a steric brake and allowing the opening of the channel. Conversely, the process of pore closing culminates with the formation of a bubble that occludes the pore even in the absence of steric block. This mechanism, known as "hydrophobic gating", has been observed in an increasing number of biological ion channels and also in artificial nanopores. Our study therefore shows promise not only to better understand the molecular origin of diseases caused by disrupted calcium signaling, but also to clarify the mode of action of hydrophobically gated ion channels, possibly even suggesting strategies for the biomimetic design of synthetic nanopores.
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Affiliation(s)
| | | | - Alberto Giacomello
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, Rome, Italy
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22
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Grieve AG, Yeh YC, Chang YF, Huang HY, Zarcone L, Breuning J, Johnson N, Stříšovský K, Brown MH, Parekh AB, Freeman M. Conformational surveillance of Orai1 by a rhomboid intramembrane protease prevents inappropriate CRAC channel activation. Mol Cell 2021; 81:4784-4798.e7. [PMID: 34800360 DOI: 10.1016/j.molcel.2021.10.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/14/2021] [Accepted: 10/26/2021] [Indexed: 12/19/2022]
Abstract
Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1. A conserved disease-linked proline residue is responsible for RHBDL2’s recognizing the active conformation of Orai1, which is required to sharpen switch-like signaling triggered by store-operated calcium entry. Loss of RHBDL2 control of CRAC channel activity causes severe dysregulation of downstream CRAC channel effectors, including transcription factor activation, inflammatory cytokine expression, and T cell activation. We propose that this surveillance function may represent an ancient activity of rhomboid proteases in degrading unwanted signaling proteins. A screen for transmembrane substrates of the rhomboid intramembrane protease RHBDL2 RHBDL2 cleaves the CRAC channel protein Orai1 when it is inappropriately activated Conformational change in these calcium channels is recognized by RHBDL2 An Orai1 mutant that cannot be cleaved by RHBDL2 causes a human disease syndrome
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23
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Huo J, Lu BZ, Dong H. Mutants only partially represent characteristics of calcium-release-activated calcium channel gating. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2111231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jun Huo
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Ben-zhuo Lu
- CEMS, LSEC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences; School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Hao Dong
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
- Institute for Brain Sciences, Nanjing University, Nanjing 210023, China
- State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
- Engineering Research Center of Protein and Peptide Medicine of Ministry of Education, Nanjing University, Nanjing 210023, China
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24
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Huang YT, Hsu YT, Chen YF, Shen MR. Super-Resolution Microscopy Reveals That Stromal Interaction Molecule 1 Trafficking Depends on Microtubule Dynamics. Front Physiol 2021; 12:762387. [PMID: 34803742 PMCID: PMC8602801 DOI: 10.3389/fphys.2021.762387] [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: 09/02/2021] [Accepted: 10/18/2021] [Indexed: 12/23/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is an essential pathway for Ca2+ signaling, and regulates various vital cellular functions. It is triggered by the endoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1). Illustration of STIM1 spatiotemporal structure at the nanometer scale during SOCE activation provides structural and functional insights into the fundamental Ca2+ homeostasis. In this study, we used direct stochastic optical reconstruction microscopy (dSTORM) to revisit the dynamic process of the interaction between STIM1, end-binding protein (EB), and microtubules to the ER-plasma membrane. Using dSTORM, we found that“powder-like”STIM1 aggregates into “trabecular-like” architectures toward the cell periphery during SOCE, and that an intact microtubule network and EB1 are essential for STIM1 trafficking. After thapsigargin treatment, STIM1 can interact with EB1 regardless of undergoing aggregation. We generated STIM1 variants adapted from a real-world database and introduced them into SiHa cells to clarify the impact of STIM1 mutations on cancer cell behavior. The p.D76G and p.D84Y variants locating on the Ca2+ binding domain of STIM1 result in inhibition of focal adhesion turnover, Ca2+ influx during SOCE and subsequent cell migration. Inversely, the p.R643C variant on the microtubule interacting domain of STIM1 leads to dissimilar consequence and aggravates cell migration. These findings imply that STIM1 mutational patterns have an impact on cancer metastasis, and therefore could be either a prognostic marker or a novel therapeutic target to inhibit the malignant behavior of STIM1-mediated cancer cells. Altogether, we generated novel insight into the role of STIM1 during SOCE activation, and uncovered the impact of real-world STIM1 variants on cancer cells.
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Affiliation(s)
- Yi-Ting Huang
- Department of Pharmacology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Basic Medical Sciences, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ya-Ting Hsu
- Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Division of Hematology, Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yih-Fung Chen
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Meng-Ru Shen
- Department of Pharmacology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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25
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Voros O, Panyi G, Hajdu P. Immune Synapse Residency of Orai1 Alters Ca 2+ Response of T Cells. Int J Mol Sci 2021; 22:ijms222111514. [PMID: 34768945 PMCID: PMC8583858 DOI: 10.3390/ijms222111514] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/11/2021] [Accepted: 10/18/2021] [Indexed: 12/19/2022] Open
Abstract
CRAC, which plays important role in Ca2+-dependent T-lymphocyte activation, is composed of the ER-resident STIM1 and the plasma membrane Orai1 pore-forming subunit. Both accumulate at the immunological synapse (IS) between a T cell and an antigen-presenting cell (APC). We hypothesized that adapter/interacting proteins regulate Orai1 residence in the IS. We could show that mGFP-tagged Orai1-Full channels expressed in Jurkat cells had a biphasic IS-accumulation kinetics peaked at 15 min. To understand the background of Orai1 IS-redistribution we knocked down STIM1 and SAP97 (adaptor protein with a short IS-residency (15 min) and ability to bind Orai1 N-terminus): the mGFP-Orai1-Full channels kept on accumulating in the IS up to the 60th minute in the STIM1- and SAP97-lacking Jurkat cells. Deletion of Orai1 N terminus (mGFP-Orai1-Δ72) resulted in the same time course as described for STIM1/SAP97 knock-down cells. Ca2+-imaging of IS-engaged T-cells revealed that of Orai1 residency modifies the Ca2+-response: cells expressing mGFP-Orai1-Δ72 construct or mGFP-Orai1-Full in SAP-97 knock-down cells showed higher number of Ca2+-oscillation up to the 90th minute after IS formation. Overall, these data suggest that SAP97 may contribute to the short-lived IS-residency of Orai1 and binding of STIM1 to Orai1 N-terminus is necessary for SAP97-Orai1 interaction.
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Affiliation(s)
- Orsolya Voros
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (O.V.); (G.P.)
| | - György Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Egyetem tér 1, 4032 Debrecen, Hungary; (O.V.); (G.P.)
| | - Péter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Dentistry, University of Debrecen, Nagyerdei krt. 98, 4032 Debrecen, Hungary
- Correspondence: ; Tel.: +36-52-258603
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26
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Kim D, Moon H, Cho H, Min C, Moon B, Yang S, Lee J, Lee SA, Park H, Lee DH, Jeong D, Lee G, Park D. Apoptotic Cells Trigger Calcium Entry in Phagocytes by Inducing the Orai1-STIM1 Association. Cells 2021; 10:2702. [PMID: 34685684 DOI: 10.3390/cells10102702] [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: 09/02/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 11/30/2022] Open
Abstract
Swift and continuous phagocytosis of apoptotic cells can be achieved by modulation of calcium flux in phagocytes. However, the molecular mechanism by which apoptotic cells modulate calcium flux in phagocytes is incompletely understood. Here, using biophysical, biochemical, pharmaceutical, and genetic approaches, we show that apoptotic cells induced the Orai1-STIM1 interaction, leading to store-operated calcium entry (SOCE) in phagocytes through the Mertk-phospholipase C (PLC) γ1-inositol 1,4,5-triphosphate receptor (IP3R) axis. Apoptotic cells induced calcium release from the endoplasmic reticulum, which led to the Orai1-STIM1 association and, consequently, SOCE in phagocytes. This association was attenuated by masking phosphatidylserine. In addition, the depletion of Mertk, which indirectly senses phosphatidylserine on apoptotic cells, reduced the phosphorylation levels of PLCγ1 and IP3R, resulting in attenuation of the Orai1-STIM1 interaction and inefficient SOCE upon apoptotic cell stimulation. Taken together, our observations uncover the mechanism of how phagocytes engulfing apoptotic cells elevate the calcium level.
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27
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de Souza LB, Ong HL, Liu X, Ambudkar IS. PIP 2 and septin control STIM1/Orai1 assembly by regulating cytoskeletal remodeling via a CDC42-WASP/WAVE-ARP2/3 protein complex. Cell Calcium 2021; 99:102475. [PMID: 34601312 DOI: 10.1016/j.ceca.2021.102475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 07/08/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 12/20/2022]
Abstract
Store-operated calcium entry (SOCE) is triggered by assembly of Orai1 with STIM proteins in ER-PM junctions. Plasma membrane PIP2 as well as PIP2-binding protein, SEPT4, significantly impact Orai1-STIM1 interaction. While septins and PIP2 can organize the actin cytoskeleton, it is unclear whether the status of actin within the junctions contributes to SOCE. We report herein that actin remodeling modulates STIM1 clustering. Our findings show that a PIP2- and SEPT4-dependent mechanism involving CDC42, WASP/WAVE, and ARP2 regulates actin remodeling into a ring-like structure around STIM1 puncta. CDC42 localization in the ER-plasma membrane region is enhanced following ER-Ca2+ store depletion. PIP2 depletion or knockdown of SEPT4 attenuate the recruitment of CDC42 to the ER-PM region. Importantly, knockdown of SEPT4, or CDC42+ARP2, disrupts the organization of actin as well as STIM1 clustering. Consequently, Orai1 recruitment to STIM1 puncta, SOCE, and NFAT translocation to the nucleus are all attenuated. Ca2+ influx induced by STIM1-C terminus is not affected by CDC42 knockdown. In aggregate, our findings reveal that PIP2 and SEPT4 affect Orai1/STIM1 clustering by coordinating actin remodeling within ER-PM junctions. This dynamic reorganization of actin has an important role in regulation of SOCE and downstream Ca2+-dependent effector functions.
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Affiliation(s)
- Lorena Brito de Souza
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA.
| | - Xibao Liu
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA.
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28
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Tiffner A, Derler I. Isoform-Specific Properties of Orai Homologues in Activation, Downstream Signaling, Physiology and Pathophysiology. Int J Mol Sci 2021; 22:8020. [PMID: 34360783 PMCID: PMC8347056 DOI: 10.3390/ijms22158020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 11/21/2022] Open
Abstract
Ca2+ ion channels are critical in a variety of physiological events, including cell growth, differentiation, gene transcription and apoptosis. One such essential entry pathway for calcium into the cell is the Ca2+ release-activated Ca2+ (CRAC) channel. It consists of the Ca2+ sensing protein, stromal interaction molecule 1 (STIM1) located in the endoplasmic reticulum (ER) and a Ca2+ ion channel Orai in the plasma membrane. The Orai channel family includes three homologues Orai1, Orai2 and Orai3. While Orai1 is the "classical" Ca2+ ion channel within the CRAC channel complex and plays a universal role in the human body, there is increasing evidence that Orai2 and Orai3 are important in specific physiological and pathophysiological processes. This makes them an attractive target in drug discovery, but requires a detailed understanding of the three Orai channels and, in particular, their differences. Orai channel activation is initiated via Ca2+ store depletion, which is sensed by STIM1 proteins, and induces their conformational change and oligomerization. Upon STIM1 coupling, Orai channels activate to allow Ca2+ permeation into the cell. While this activation mechanism is comparable among the isoforms, they differ by a number of functional and structural properties due to non-conserved regions in their sequences. In this review, we summarize the knowledge as well as open questions in our current understanding of the three isoforms in terms of their structure/function relationship, downstream signaling and physiology as well as pathophysiology.
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Affiliation(s)
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria;
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29
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Baraniak JH, Zhou Y, Nwokonko RM, Jennette MR, Kazzaz SA, Stenson JM, Whitsell AL, Wang Y, Trebak M, Gill DL. Orai channel C-terminal peptides are key modulators of STIM-Orai coupling and calcium signal generation. Cell Rep 2021; 35:109322. [PMID: 34192542 PMCID: PMC8462482 DOI: 10.1016/j.celrep.2021.109322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/17/2021] [Accepted: 06/07/2021] [Indexed: 11/03/2022] Open
Abstract
Junctional coupling between endoplasmic reticulum (ER) Ca2+-sensor STIM proteins and plasma membrane (PM) Orai channels mediates Ca2+ signals in most cells. We reveal that PM-tethered, fluorescently tagged C-terminal M4x (fourth transmembrane helix contains a cytoplasmic C-terminal extension) peptides from Orai channels undergo a Leu-specific signature of direct interaction with the STIM1 Orai-activating region (SOAR), exactly mimicking STIM1 binding to gate Orai channels. The 20-amino-acid Orai3-M4x peptide associates avidly with STIM1 within ER-PM junctions, functions to competitively block native Ca2+ signals, and mediates a key modification of STIM-Orai coupling induced by 2-aminoethoxydiphenyl borate. By blocking STIM-Orai coupling, the Orai3-M4x peptide reveals the critical role of Orai channels in driving Ca2+ oscillatory signals and transcriptional control through NFAT. The M4x peptides interact independently with SOAR dimers consistent with unimolecular coupling between Orai subunits and STIM1 dimers. We reveal the critical role of M4x helices in defining the coupling interface between STIM and Orai proteins to mediate store-operated Ca2+ signals.
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Affiliation(s)
- James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
| | - Robert M Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Michelle R Jennette
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Sarah A Kazzaz
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Jazmin M Stenson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Abigale L Whitsell
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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30
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Souza Bomfim GH, Mitaishvili E, Aguiar TF, Lacruz RS. Mibefradil alters intracellular calcium concentration by activation of phospholipase C and IP 3 receptor function. Mol Biomed 2021; 2:12. [PMID: 35006468 PMCID: PMC8607413 DOI: 10.1186/s43556-021-00037-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/24/2021] [Indexed: 11/25/2022] Open
Abstract
Mibefradil is a tetralol derivative originally developed as an antagonist of T-type voltage-gated calcium (Ca2+) channels to treat hypertension when used at nanomolar dosage. More recently, its therapeutic application in hypertension has declined and has been instead repurposed as a treatment of cancer cell proliferation and solid tumor growth. Beyond its function as a Cav blocker, the micromolar concentration of mibefradil can stimulate a rise in [Ca2+]cyt although the mechanism is poorly known. The chanzyme TRPM7 (transient receptor potential melastanin 7), the release of intracellular Ca2+ pools, and Ca2+ influx by ORAI channels have been associated with the increase in [Ca2+]cyt triggered by mibefradil. This study aims to investigate the cellular targets and pathways associated with mibefradil's effect on [Ca2+]cyt. To address these questions, we monitored changes in [Ca2+]cyt in the specialized mouse epithelial cells (LS8 and ALC) and the widely used HEK-293 cells by stimulating these cells with mibefradil (0.1 μM to 100 μM). We show that mibefradil elicits an increase in [Ca2+]cyt at concentrations above 10 μM (IC50 around 50 μM) and a fast Ca2+ increase capacity at 100 μM. We found that inhibiting IP3 receptors, depleting the ER-Ca2+ stores, or blocking phospholipase C (PLC), significantly decreased the capacity of mibefradil to elevate [Ca2+]cyt. Moreover, the transient application of 100 μM mibefradil triggered Ca2+ influx by store-operated Ca2+ entry (SOCE) mediated by the ORAI channels. Our findings reveal that IP3R and PLC are potential new targets of mibefradil offering novel insights into the effects of this drug.
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Affiliation(s)
- Guilherme H Souza Bomfim
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA
| | - Erna Mitaishvili
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA
| | | | - Rodrigo S Lacruz
- Department of Molecular Pathobiology, New York University College of Dentistry, New York, NY, 10010, USA.
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31
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Yamashita M, Prakriya M. Interrogating permeation and gating of Orai channels using chemical modification of cysteine residues. Methods Enzymol 2021; 652:213-239. [PMID: 34059283 DOI: 10.1016/bs.mie.2021.02.012] [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] [Indexed: 11/20/2022]
Abstract
Chemical modification of ion channels using the substituted cysteine accessibility method has a rich and successful history in elucidating the structural basis of ion channel function. In this approach, cysteine residues are introduced in regions of interest into the protein and their accessibility to water soluble thiol-reactive reagents is determined by monitoring ion channel activity. Because a wide range of these reagents are available with differing size, charge, and membrane solubility, the physio-chemical environment of the introduced cysteine residue and therefore the protein domain of interest can be probed with great precision. The approach has been widely employed for determining the secondary structure of specific ion channel domains, the location and nature of the channel gate, and the conformational rearrangements in the channel pore that underlie the opening/closing of the pore. In this chapter, we describe the use of these and related approaches to probe the functional architecture and gating of store-operated Orai1 channels.
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Affiliation(s)
- Megumi Yamashita
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States.
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32
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Emrich SM, Yoast RE, Xin P, Arige V, Wagner LE, Hempel N, Gill DL, Sneyd J, Yule DI, Trebak M. Omnitemporal choreographies of all five STIM/Orai and IP 3Rs underlie the complexity of mammalian Ca 2+ signaling. Cell Rep 2021; 34:108760. [PMID: 33657364 PMCID: PMC7968378 DOI: 10.1016/j.celrep.2021.108760] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [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: 10/10/2020] [Revised: 12/16/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
Stromal-interaction molecules (STIM1/2) sense endoplasmic reticulum (ER) Ca2+ depletion and activate Orai channels. However, the choreography of interactions between native STIM/Orai proteins under physiological agonist stimulation is unknown. We show that the five STIM1/2 and Orai1/2/3 proteins are non-redundant and function together to ensure the graded diversity of mammalian Ca2+ signaling. Physiological Ca2+ signaling requires functional interactions between STIM1/2, Orai1/2/3, and IP3Rs, ensuring that receptor-mediated Ca2+ release is tailored to Ca2+ entry and nuclear factor of activated T cells (NFAT) activation. The N-terminal Ca2+-binding ER-luminal domains of unactivated STIM1/2 inhibit IP3R-evoked Ca2+ release. A gradual increase in agonist intensity and STIM1/2 activation relieves IP3R inhibition. Concomitantly, activated STIM1/2 C termini differentially interact with Orai1/2/3 as agonist intensity increases. Thus, coordinated and omnitemporal functions of all five STIM/Orai and IP3Rs translate the strength of agonist stimulation to precise levels of Ca2+ signaling and NFAT induction, ensuring the fidelity of complex mammalian Ca2+ signaling.
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Affiliation(s)
- Scott M Emrich
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Ryan E Yoast
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Ping Xin
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Vikas Arige
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Larry E Wagner
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Nadine Hempel
- Department of Pharmacology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Penn State Cancer Institute, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - James Sneyd
- Department of Mathematics, The University of Auckland, 38 Princes Street, Auckland 1010, New Zealand
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA; Penn State Cancer Institute, the Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA.
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33
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Affiliation(s)
- Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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34
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Abstract
Store-operated Orai channels are a primary mechanism for mobilizing Ca2+ signals in both non-excitable cells and excitable cells. The structure of the open channel, vital for understanding the mechanism of channel opening, is incompletely understood. We highlight a new study that unveils the structure of a constitutively active Orai mutant and takes us closer towards understanding the molecular basis of Orai channel activation.
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Affiliation(s)
- Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, United States.
| | - Priscilla See-Wai Yeung
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, United States
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, United States
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35
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Hodeify R, Dib M, Alcantara-Adap E, Courjaret R, Nader N, Reyes CZ, Hammad AS, Hubrack S, Yu F, Machaca K. The carboxy terminal coiled-coil modulates Orai1 internalization during meiosis. Sci Rep 2021; 11:2290. [PMID: 33504898 PMCID: PMC7840751 DOI: 10.1038/s41598-021-82048-z] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/30/2020] [Indexed: 12/19/2022] Open
Abstract
Regulation of Ca2+ signaling is critical for the progression of cell division, especially during meiosis to prepare the egg for fertilization. The primary Ca2+ influx pathway in oocytes is Store-Operated Ca2+ Entry (SOCE). SOCE is tightly regulated during meiosis, including internalization of the SOCE channel, Orai1. Orai1 is a four-pass membrane protein with cytosolic N- and C-termini. Orai1 internalization requires a caveolin binding motif (CBM) in the N-terminus as well as the C-terminal cytosolic domain. However, the molecular determinant for Orai1 endocytosis in the C-terminus are not known. Here we show that the Orai1 C-terminus modulates Orai1 endocytosis during meiosis through a structural motif that is based on the strength of the C-terminal intersubunit coiled coil (CC) domains. Deletion mutants show that a minimal C-terminal sequence after transmembrane domain 4 (residues 260–275) supports Orai1 internalization. We refer to this region as the C-terminus Internalization Handle (CIH). Access to CIH however is dependent on the strength of the intersubunit CC. Mutants that increase the stability of the coiled coil prevent internalization independent of specific mutation. We further used human and Xenopus Orai isoforms with different propensity to form C-terminal CC and show a strong correlation between the strength of the CC and Orai internalization. Furthermore, Orai1 internalization does not depend on clathrin, flotillin or PIP2. Collectively these results argue that Orai1 internalization requires both the N-terminal CBM and C-terminal CIH where access to CIH is controlled by the strength of intersubunit C-terminal CC.
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Affiliation(s)
- Rawad Hodeify
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.,Department of Biotechnology, American University of Ras Al Khaimah, Ras al Khaimah, UAE
| | - Maya Dib
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Ethel Alcantara-Adap
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Raphael Courjaret
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Nancy Nader
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Cleo Z Reyes
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.,Lehigh Valley Health Network, Allentown, PA, USA
| | - Ayat S Hammad
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Satanay Hubrack
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.,Sidra Medicine, Doha, Qatar
| | - Fang Yu
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Khaled Machaca
- Department of Physiology and Biophysics, Ca2+ signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.
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36
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He L, Wang L, Zeng H, Tan P, Ma G, Zheng S, Li Y, Sun L, Dou F, Siwko S, Huang Y, Wang Y, Zhou Y. Engineering of a bona fide light-operated calcium channel. Nat Commun 2021; 12:164. [PMID: 33431868 PMCID: PMC7801460 DOI: 10.1038/s41467-020-20425-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/25/2020] [Indexed: 12/17/2022] Open
Abstract
The current optogenetic toolkit lacks a robust single-component Ca2+-selective ion channel tailored for remote control of Ca2+ signaling in mammals. Existing tools are either derived from engineered channelrhodopsin variants without strict Ca2+ selectivity or based on the stromal interaction molecule 1 (STIM1) that might crosstalk with other targets. Here, we describe the design of a light-operated Ca2+ channel (designated LOCa) by inserting a plant-derived photosensory module into the intracellular loop of an engineered ORAI1 channel. LOCa displays biophysical features reminiscent of the ORAI1 channel, which enables precise optical control over Ca2+ signals and hallmark Ca2+-dependent physiological responses. Furthermore, we demonstrate the use of LOCa to modulate aberrant hematopoietic stem cell self-renewal, transcriptional programming, cell suicide, as well as neurodegeneration in a Drosophila model of amyloidosis. Existing optogenetic methods to induce calcium mobilisation lack selectivity and specificity. Here, the authors design and engineer a single-component light-operated calcium channel to provide optical control over calcium signals and calcium-dependent physiological responses: LOCa.
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Affiliation(s)
- Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA
| | - Liuqing Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Hongxiang Zeng
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA
| | - Peng Tan
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA
| | - Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA
| | - Sisi Zheng
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Yaxin Li
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Lin Sun
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Fei Dou
- Beijing Key Laboratory of Genetic Engineering Drugs and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Stefan Siwko
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA. .,Department of Translational Medical Sciences, College of Medicine, Texas A&M University, Houston, TX, USA.
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China.
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, USA. .,Department of Translational Medical Sciences, College of Medicine, Texas A&M University, Houston, TX, USA.
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37
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Abstract
Cell survival and normal cell function require a highly coordinated and precise regulation of basal cytosolic Ca2+ concentrations. The primary source of Ca2+ entry into the cell is mediated by the Ca2+ release-activated Ca2+ (CRAC) channel. Its action is stimulated in response to internal Ca2+ store depletion. The fundamental constituents of CRAC channels are the Ca2+ sensor, stromal interaction molecule 1 (STIM1) anchored in the endoplasmic reticulum, and a highly Ca2+-selective pore-forming subunit Orai1 in the plasma membrane. The precise nature of the Orai1 pore opening is currently a topic of intensive research. This review describes how Orai1 gating checkpoints in the middle and cytosolic extended transmembrane regions act together in a concerted manner to ensure an opening-permissive Orai1 channel conformation. In this context, we highlight the effects of the currently known multitude of Orai1 mutations, which led to the identification of a series of gating checkpoints and the determination of their role in diverse steps of the Orai1 activation cascade. The synergistic action of these gating checkpoints maintains an intact pore geometry, settles STIM1 coupling, and governs pore opening. We describe the current knowledge on Orai1 channel gating mechanisms and summarize still open questions of the STIM1-Orai1 machinery.
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38
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Tiffner A, Schober R, Höglinger C, Bonhenry D, Pandey S, Lunz V, Sallinger M, Frischauf I, Fahrner M, Lindinger S, Maltan L, Berlansky S, Stadlbauer M, Schindl R, Ettrich R, Romanin C, Derler I. CRAC channel opening is determined by a series of Orai1 gating checkpoints in the transmembrane and cytosolic regions. J Biol Chem 2021; 296:100224. [PMID: 33361160 PMCID: PMC7948504 DOI: 10.1074/jbc.ra120.015548] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/15/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022] Open
Abstract
The initial activation step in the gating of ubiquitously expressed Orai1 calcium (Ca2+) ion channels represents the activation of the Ca2+-sensor protein STIM1 upon Ca2+ store depletion of the endoplasmic reticulum. Previous studies using constitutively active Orai1 mutants gave rise to, but did not directly test, the hypothesis that STIM1-mediated Orai1 pore opening is accompanied by a global conformational change of all Orai transmembrane domain (TM) helices within the channel complex. We prove that a local conformational change spreads omnidirectionally within the Orai1 complex. Our results demonstrate that these locally induced global, opening-permissive TM motions are indispensable for pore opening and require clearance of a series of Orai1 gating checkpoints. We discovered these gating checkpoints in the middle and cytosolic extended TM domain regions. Our findings are based on a library of double point mutants that contain each one loss-of-function with one gain-of-function point mutation in a series of possible combinations. We demonstrated that an array of loss-of-function mutations are dominant over most gain-of-function mutations within the same as well as of an adjacent Orai subunit. We further identified inter- and intramolecular salt-bridge interactions of Orai subunits as a core element of an opening-permissive Orai channel architecture. Collectively, clearance and synergistic action of all these gating checkpoints are required to allow STIM1 coupling and Orai1 pore opening. Our results unravel novel insights in the preconditions of the unique fingerprint of CRAC channel activation, provide a valuable source for future structural resolutions, and help to understand the molecular basis of disease-causing mutations.
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Affiliation(s)
- Adéla Tiffner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Romana Schober
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Carmen Höglinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Nove Hrady, Czechia
| | - Saurabh Pandey
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Sciences, Nove Hrady, Czechia
| | - Victoria Lunz
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Matthias Sallinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Marc Fahrner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Sonja Lindinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Lena Maltan
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Sascha Berlansky
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Michael Stadlbauer
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Rudiger Ettrich
- College of Biomedical Sciences, Larkin University, Miami, Florida, USA; Faculty of Mathematics and Physics, Charles University, Prague, Czechia; Department of Cellular Biology & Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Christoph Romanin
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria.
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39
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Tiffner A, Derler I. Molecular Choreography and Structure of Ca 2+ Release-Activated Ca 2+ (CRAC) and K Ca2+ Channels and Their Relevance in Disease with Special Focus on Cancer. Membranes (Basel) 2020; 10:membranes10120425. [PMID: 33333945 PMCID: PMC7765462 DOI: 10.3390/membranes10120425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
Ca2+ ions play a variety of roles in the human body as well as within a single cell. Cellular Ca2+ signal transduction processes are governed by Ca2+ sensing and Ca2+ transporting proteins. In this review, we discuss the Ca2+ and the Ca2+-sensing ion channels with particular focus on the structure-function relationship of the Ca2+ release-activated Ca2+ (CRAC) ion channel, the Ca2+-activated K+ (KCa2+) ion channels, and their modulation via other cellular components. Moreover, we highlight their roles in healthy signaling processes as well as in disease with a special focus on cancer. As KCa2+ channels are activated via elevations of intracellular Ca2+ levels, we summarize the current knowledge on the action mechanisms of the interplay of CRAC and KCa2+ ion channels and their role in cancer cell development.
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40
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Hou X, Outhwaite IR, Pedi L, Long SB. Cryo-EM structure of the calcium release-activated calcium channel Orai in an open conformation. eLife 2020; 9:62772. [PMID: 33252040 PMCID: PMC7723414 DOI: 10.7554/elife.62772] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 09/04/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022] Open
Abstract
The calcium release-activated calcium channel Orai regulates Ca2+ entry into non-excitable cells and is required for proper immune function. While the channel typically opens following Ca2+ release from the endoplasmic reticulum, certain pathologic mutations render the channel constitutively open. Previously, using one such mutation (H206A), we obtained low (6.7 Å) resolution X-ray structural information on Drosophila melanogaster Orai in an open conformation (Hou et al., 2018). Here we present a structure of this open conformation at 3.3 Å resolution using fiducial-assisted cryo-electron microscopy. The improved structure reveals the conformations of amino acids in the open pore, which dilates by outward movements of subunits. A ring of phenylalanine residues repositions to expose previously shielded glycine residues to the pore without significant rotational movement of the associated helices. Together with other hydrophobic amino acids, the phenylalanines act as the channel's gate. Structured M1-M2 turrets, not evident previously, form the channel's extracellular entrance.
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Affiliation(s)
- Xiaowei Hou
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Ian R Outhwaite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Leanne Pedi
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Stephen Barstow Long
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
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41
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Yeung PSW, Ing CE, Yamashita M, Pomès R, Prakriya M. A sulfur-aromatic gate latch is essential for opening of the Orai1 channel pore. eLife 2020; 9:60751. [PMID: 33124982 PMCID: PMC7679135 DOI: 10.7554/elife.60751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 07/06/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Sulfur-aromatic interactions occur in the majority of protein structures, yet little is known about their functional roles in ion channels. Here, we describe a novel molecular motif, the M101 gate latch, which is essential for gating of human Orai1 channels via its sulfur-aromatic interactions with the F99 hydrophobic gate. Molecular dynamics simulations of different Orai variants reveal that the gate latch is mostly engaged in open but not closed channels. In experimental studies, we use metal-ion bridges to show that promoting an M101-F99 bond directly activates Orai1, whereas disrupting this interaction triggers channel closure. Mutational analysis demonstrates that the methionine residue at this position has a unique combination of length, flexibility, and chemistry to act as an effective latch for the phenylalanine gate. Because sulfur-aromatic interactions provide additional stabilization compared to purely hydrophobic interactions, we infer that the six M101-F99 pairs in the hexameric channel provide a substantial energetic contribution to Orai1 activation.
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Affiliation(s)
- Priscilla S-W Yeung
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, United States
| | - Christopher E Ing
- Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, United States
| | - Régis Pomès
- Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, United States
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42
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Drumm BT, Thornbury KD, Hollywood MA, Sergeant GP. Store-operated Ca 2+ influx in native vascular smooth muscle cells relies on interactions between PKCδ, PIP 2 and TRPC1 channels. J Physiol 2020; 599:1037-1038. [PMID: 33080052 DOI: 10.1113/jp280807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 10/16/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Bernard T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
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43
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Zhang W, Muramatsu A, Matsuo R, Teranishi N, Kahara Y, Takahara T, Shibata H, Maki M. The Penta-EF-Hand ALG-2 Protein Interacts with the Cytosolic Domain of the SOCE Regulator SARAF and Interferes with Ubiquitination. Int J Mol Sci 2020; 21:E6315. [PMID: 32878247 DOI: 10.3390/ijms21176315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 07/27/2020] [Revised: 08/24/2020] [Accepted: 08/29/2020] [Indexed: 12/18/2022] Open
Abstract
ALG-2 is a penta-EF-hand Ca2+-binding protein and interacts with a variety of proteins in mammalian cells. In order to find new ALG-2-binding partners, we searched a human protein database and retrieved sequences containing the previously identified ALG-2-binding motif type 2 (ABM-2). After selecting 12 high-scored sequences, we expressed partial or full-length GFP-fused proteins in HEK293 cells and performed a semi-quantitative in vitro binding assay. SARAF, a negative regulator of store-operated Ca2+ entry (SOCE), showed the strongest binding activity. Biochemical analysis of Strep-tagged and GFP-fused SARAF proteins revealed ubiquitination that proceeded during pulldown assays under certain buffer conditions. Overexpression of ALG-2 interfered with ubiquitination of wild-type SARAF but not ubiquitination of the F228S mutant that had impaired ALG-2-binding activity. The SARAF cytosolic domain (CytD) contains two PPXY motifs targeted by the WW domains of NEDD4 family E3 ubiquitin ligases. The PPXY motif proximal to the ABM-2 sequence was found to be more important for both in-cell ubiquitination and post-cell lysis ubiquitination. A ubiquitination-defective mutant of SARAF with Lys-to-Arg substitutions in the CytD showed a slower degradation rate by half-life analysis. ALG-2 promoted Ca2+-dependent CytD-to-CytD interactions of SARAF. The ALG-2 dimer may modulate the stability of SARAF by sterically blocking ubiquitination and by bridging SARAF molecules at the CytDs.
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44
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Zhang X, Xin P, Yoast RE, Emrich SM, Johnson MT, Pathak T, Benson JC, Azimi I, Gill DL, Monteith GR, Trebak M. Distinct pharmacological profiles of ORAI1, ORAI2, and ORAI3 channels. Cell Calcium 2020; 91:102281. [PMID: 32896813 DOI: 10.1016/j.ceca.2020.102281] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [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: 08/05/2020] [Revised: 08/25/2020] [Accepted: 08/25/2020] [Indexed: 12/18/2022]
Abstract
The ubiquitous Ca2+ release-activated Ca2+ (CRAC) channel is crucial to many physiological functions. Both gain and loss of CRAC function is linked to disease. While ORAI1 is a crucial subunit of CRAC channels, recent evidence suggests that ORAI2 and ORAI3 heteromerize with ORAI1 to form native CRAC channels. Furthermore, ORAI2 and ORAI3 can form CRAC channels independently of ORAI1, suggesting diverse native CRAC stoichiometries. Yet, most available CRAC modifiers are presumed to target ORAI1 with little knowledge of their effects on ORAI2/3 or heteromers of ORAIs. Here, we used ORAI1/2/3 triple-null cells to express individual ORAI1, ORAI2, ORAI3 or ORAI1/2/3 concatemers. We reveal that GSK-7975A and BTP2 essentially abrogate ORAI1 and ORAI2 activity while causing only a partial inhibition of ORAI3. Interestingly, Synta66 abrogated ORAI1 channel function, while potentiating ORAI2 with no effect on ORAI3. CRAC channel activities mediated by concatenated ORAI1-1, ORAI1-2 and ORAI1-3 dimers were inhibited by Synta66, while ORAI2-3 dimers were unaffected. The CRAC enhancer IA65 significantly potentiated ORAI1 and ORAI1-1 activity with marginal effects on other ORAIs. Further, we characterized the profiles of individual ORAI isoforms in the presence of Gd3+ (5μM), 2-APB (5 μM and 50 μM), as well as changes in intracellular and extracellular pH. Our data reveal unique pharmacological features of ORAI isoforms expressed in an ORAI-null background and provide new insights into ORAI isoform selectivity of widely used CRAC pharmacological compounds.
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Affiliation(s)
- Xuexin Zhang
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA.
| | - Ping Xin
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Ryan E Yoast
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Scott M Emrich
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Martin T Johnson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Trayambak Pathak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - J Cory Benson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Iman Azimi
- School of Pharmacy and Pharmacology, College of Health and Medicine, University of Tasmania, Hobart 7001, Tasmania, Australia
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA
| | - Gregory R Monteith
- School of Pharmacy, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA; Penn State Cancer Institute, The Pennsylvania State University College of Medicine, 500 University Dr. Hershey, PA, 17033 USA.
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45
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Abstract
Store-operated Ca2+ entry signals are critical for cellular regulation. This intricate signaling pathway involves coupling of proteins in two different membranes: the ER-resident Ca2+-sensing STIM proteins and the highly Ca2+-selective PM Orai channels. The molecular nature of the STIM-Orai coupling interface in ER-PM junctions and consequent Orai channel gating, are processes under intense study. We describe recent developments in determining the mechanism of Orai activation through the key STIM-Orai Activating Region (SOAR) of STIM1. We describe the unexpected unimolecular coupling of STIM with Orai and explain the observed variable stoichiometry of STIM-Orai interactions. We also define the discrete C-terminal regions in Orai channels that initially latch onto STIM proteins and mediate allosteric activation of the channel. A critical "nexus" region closely associated with the STIM-activated C-terminus of Orai1, propagates the STIM-binding signal through the four tightly-associated transmembrane helices of Orai1, finally to modify the pore-forming helices and effect channel opening.
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Affiliation(s)
- James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Robert M Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
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46
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Niu L, Wu F, Li K, Li J, Zhang SL, Hu J, Wang Q. STIM1 interacts with termini of Orai channels in a sequential manner. J Cell Sci 2020; 133:jcs239491. [PMID: 32107289 DOI: 10.1242/jcs.239491] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is critical for numerous Ca2+-related processes. The activation of SOCE requires engagement between stromal interaction molecule 1 (STIM1) molecules on the endoplasmic reticulum and Ca2+ release-activated channel (CRAC) Orai on the plasma membrane. However, the molecular details of their interactions remain elusive. Here, we analyzed STIM1-Orai interactions using synthetic peptides derived from the N- and C-termini of Orai channels (Orai-NT and Orai-CT, respectively) and purified fragments of STIM1. The binding of STIM1 to Orai-NT is hydrophilic based, whereas binding to the Orai-CT is mostly hydrophobic. STIM1 decreases its affinity for Orai-CT when Orai-NT is present, supporting a stepwise interaction. Orai3-CT exhibits stronger binding to STIM1 than Orai1-CT, largely due to the shortness of one helical turn. The role of newly identified residues was confirmed by co-immunoprecipitation and Ca2+ imaging using full-length molecules. Our results provide important insight into CRAC gating by STIM1.
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Affiliation(s)
- Liling Niu
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, and Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin 300070, China
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Fuyun Wu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
- School of Basic Medical Sciences, Hubei University of Medicine, Shiyan 442000, China
| | - Kaili Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jing Li
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shenyuan L Zhang
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, TX 76504, USA
| | - Junjie Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Wang
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, and Tianjin Key Laboratory of Cellular and Molecular Immunology, Tianjin 300070, China
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47
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Abstract
Calcium signals drive an endless array of cellular responses including secretion, contraction, transcription, cell division, and growth. The ubiquitously expressed Orai family of plasma membrane (PM) ion channels mediate Ca2+ entry signals triggered by the Ca2+ sensor Stromal Interaction Molecule (STIM) proteins of the endoplasmic reticulum (ER). The 2 proteins interact within curiously obscure ER-PM junctions, driving an allosteric gating mechanism for the Orai channel. Although key to Ca2+ signal generation, molecular understanding of this activation process remain obscure. Crystallographic structural analyses reveal much about the exquisite hexameric core structure of Orai channels. But how STIM proteins bind to the channel periphery and remotely control opening of the central pore, has eluded such analysis. Recent studies apply both crystallography and single-particle cryogenic electron microscopy (cryo-EM) analyses to probe the structure of Orai mutants that mimic activation by STIM. The results provide new understanding on the open state of the channel and how STIM proteins may exert remote allosteric control of channel gating. Plasma membrane Orai channels are activated by endoplasmic reticulum calcium-sensing STIM proteins through a dynamic coupling mechanism within specialized inter-membrane junctions. This Primer explores new structural studies that hint at the extraordinary complexity of this crucial association that is critical to the generation of calcium signals.
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Affiliation(s)
- Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail: (DLG); (YZ)
| | - Robert M. Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - James H. Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Kenneth P. K. Lee
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Donald L. Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail: (DLG); (YZ)
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