1
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Clarke A, Skerjanz J, Gsell MAF, Wiedner P, Erkan-Candag H, Groschner K, Stockner T, Tiapko O. PIP 2 modulates TRPC3 activity via TRP helix and S4-S5 linker. Nat Commun 2024; 15:5220. [PMID: 38890374 PMCID: PMC11189476 DOI: 10.1038/s41467-024-49396-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 06/04/2024] [Indexed: 06/20/2024] Open
Abstract
The transient receptor potential canonical type 3 (TRPC3) channel plays a pivotal role in regulating neuronal excitability in the brain via its constitutive activity. The channel is intricately regulated by lipids and has previously been demonstrated to be positively modulated by PIP2. Using molecular dynamics simulations and patch clamp techniques, we reveal that PIP2 predominantly interacts with TRPC3 at the L3 lipid binding site, located at the intersection of pre-S1 and S1 helices. We demonstrate that PIP2 sensing involves a multistep mechanism that propagates from L3 to the pore domain via a salt bridge between the TRP helix and S4-S5 linker. Notably, we find that both stimulated and constitutive TRPC3 activity require PIP2. These structural insights into the function of TRPC3 are invaluable for understanding the role of the TRPC subfamily in health and disease, in particular for cardiovascular diseases, in which TRPC3 channels play a major role.
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Affiliation(s)
- Amy Clarke
- Department of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Julia Skerjanz
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria
| | - Mathias A F Gsell
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria
| | - Patrick Wiedner
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria
| | - Hazel Erkan-Candag
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria
| | - Klaus Groschner
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria
| | - Thomas Stockner
- Department of Pharmacology, Medical University of Vienna, Vienna, Austria.
| | - Oleksandra Tiapko
- Division of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria.
- BioTechMed, 8010, Graz, Austria.
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2
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Asunción-Alvarez D, Palacios J, Ybañez-Julca RO, Rodriguez-Silva CN, Nwokocha C, Cifuentes F, Greensmith DJ. Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens. Am J Physiol Heart Circ Physiol 2024; 326:H950-H970. [PMID: 38334967 DOI: 10.1152/ajpheart.00600.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.
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Affiliation(s)
- Daniel Asunción-Alvarez
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Javier Palacios
- Laboratorio de Bioquímica Aplicada, Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile
| | - Roberto O Ybañez-Julca
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Cristhian N Rodriguez-Silva
- Departamento de Farmacología, Facultad de Farmacia y Bioquímica, Universidad Nacional de Trujillo, Trujillo, Perú
| | - Chukwuemeka Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Kingston, Jamaica
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EphyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - David J Greensmith
- Biomedical Research Centre, School of Science, Engineering and Environment, The University of Salford, Salford, United Kingdom
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3
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Rohacs T. Phosphoinositide Regulation of TRP Channels: A Functional Overview in the Structural Era. Annu Rev Physiol 2024; 86:329-355. [PMID: 37871124 DOI: 10.1146/annurev-physiol-042022-013956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Transient receptor potential (TRP) ion channels have diverse activation mechanisms including physical stimuli, such as high or low temperatures, and a variety of intracellular signaling molecules. Regulation by phosphoinositides and their derivatives is their only known common regulatory feature. For most TRP channels, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] serves as a cofactor required for activity. Such dependence on PI(4,5)P2 has been demonstrated for members of the TRPM subfamily and for the epithelial TRPV5 and TRPV6 channels. Intracellular TRPML channels show specific activation by PI(3,5)P2. Structural studies uncovered the PI(4,5)P2 and PI(3,5)P2 binding sites for these channels and shed light on the mechanism of channel opening. PI(4,5)P2 regulation of TRPV1-4 as well as some TRPC channels is more complex, involving both positive and negative effects. This review discusses the functional roles of phosphoinositides in TRP channel regulation and molecular insights gained from recent cryo-electron microscopy structures.
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Affiliation(s)
- Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey;
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4
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Zhao T, Parmisano S, Soroureddin Z, Zhao M, Yung L, Thistlethwaite PA, Makino A, Yuan JXJ. Mechanosensitive cation currents through TRPC6 and Piezo1 channels in human pulmonary arterial endothelial cells. Am J Physiol Cell Physiol 2022; 323:C959-C973. [PMID: 35968892 PMCID: PMC9485000 DOI: 10.1152/ajpcell.00313.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/09/2022] [Accepted: 08/09/2022] [Indexed: 11/22/2022]
Abstract
Mechanosensitive cation channels and Ca2+ influx through these channels play an important role in the regulation of endothelial cell functions. Transient receptor potential canonical channel 6 (TRPC6) is a diacylglycerol-sensitive nonselective cation channel that forms receptor-operated Ca2+ channels in a variety of cell types. Piezo1 is a mechanosensitive cation channel activated by membrane stretch and shear stress in lung endothelial cells. In this study, we report that TRPC6 and Piezo1 channels both contribute to membrane stretch-mediated cation currents and Ca2+ influx or increase in cytosolic-free Ca2+ concentration ([Ca2+]cyt) in human pulmonary arterial endothelial cells (PAECs). The membrane stretch-mediated cation currents and increase in [Ca2+]cyt in human PAECs were significantly decreased by GsMTX4, a blocker of Piezo1 channels, and by BI-749327, a selective blocker of TRPC6 channels. Extracellular application of 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane permeable analog of diacylglycerol, rapidly induced whole cell cation currents and increased [Ca2+]cyt in human PAECs and human embryonic kidney (HEK)-cells transiently transfected with the human TRPC6 gene. Furthermore, membrane stretch with hypo-osmotic or hypotonic solution enhances the cation currents in TRPC6-transfected HEK cells. In HEK cells transfected with the Piezo1 gene, however, OAG had little effect on the cation currents, but membrane stretch significantly enhanced the cation currents. These data indicate that, while both TRPC6 and Piezo1 are involved in generating mechanosensitive cation currents and increases in [Ca2+]cyt in human PAECs undergoing mechanical stimulation, only TRPC6 (but not Piezo1) is sensitive to the second messenger diacylglycerol. Selective blockers of these channels may help develop novel therapies for mechanotransduction-associated pulmonary vascular remodeling in patients with pulmonary arterial hypertension.
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Affiliation(s)
- Tengteng Zhao
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
| | - Sophia Parmisano
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
| | - Zahra Soroureddin
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
| | - Manjia Zhao
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
| | - Lauren Yung
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
| | - Patricia A Thistlethwaite
- Division of Cardiothoracic Surgery, Department of Surgery, University of California, San Diego, California
| | - Ayako Makino
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, California
| | - Jason X-J Yuan
- Section of Physiology, Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California
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5
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Critical contributions of pre-S1 shoulder and distal TRP box in DAG-activated TRPC6 channel by PIP 2 regulation. Sci Rep 2022; 12:10766. [PMID: 35750783 PMCID: PMC9232555 DOI: 10.1038/s41598-022-14766-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/13/2022] [Indexed: 11/25/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2) regulates the activities of numerous membrane proteins, including diacylglycerol(DAG)-activated TRPC3/6/7 channels. Although PIP2 binding is known to support DAG-activated TRP channel activity, its binding site remains unknown. We screened for PIP2 binding sites within TRPC6 channels through extensive mutagenesis. Using voltage-sensitive phosphatase (DrVSP), we found that Arg437 and Lys442, located in the channel’s pre-S1 domain/shoulder, are crucial for interaction with PIP2. To gain structural insights, we conducted computer protein–ligand docking simulations with the pre-S1 domain/shoulder of TRPC6 channels. Further, the functional significance of PIP2 binding to the pre-S1 shoulder was assessed for receptor-operated channel functions, cross-reactivity to DAG activation, and the kinetic model simulation. These results revealed that basic residues in the pre-S1 domain/shoulder play a central role in the regulation of PIP2-dependent gating. In addition, neutralizing mutation of K771 in the distal TRP box reversed the effect of PIP2 depletion from inhibiting to potentiating channel activity. A similar effect was seen in TRPV1 channels, which suggests that TRPC6 possesses a common but robust polarity switch mediating the PIP2-dependent effect. Overall, these mutagenesis studies reveal functional and structural insights for how basic residues and channel segments in TRP channels are controlled through phosphoinositides recognition.
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6
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Liu H, Lin WY, Leibow SR, Morateck AJ, Ahuja M, Muallem S. TRPC3 channel gating by lipids requires localization at the ER/PM junctions defined by STIM1. J Biophys Biochem Cytol 2022; 221:213134. [PMID: 35416932 PMCID: PMC9011324 DOI: 10.1083/jcb.202107120] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/08/2021] [Accepted: 03/08/2022] [Indexed: 12/21/2022] Open
Abstract
TRPC3, a member of the transient receptor potential (TRP) superfamily of cation channels, is a lipid-regulated, Ca2+-permeable channel that mediates essential components of the receptor evoked Ca2+ signal. The modes and mechanisms by which lipids regulate TRPC3 and other members of the TRPC channel family are not well understood. Here, we report that PI(4,5)P2 regulates TRPC3 in three independent modes. PLC-dependent hydrolysis generates diacylglycerol (DAG) that interacts with lipid-binding site 2 in the channel pore. PI(4,5)P2 interacts with lipid site 1 to inhibit TRPC3 opening and regulate access of DAG to the pore lipid site 2. PI(4,5)P2 is required for regulating pore ionic selectivity by receptor stimulation. Notably, the activation and regulation of TRPC3 by PI(4,5)P2 require recruitment of TRPC3 to the ER/PM junctions at a PI(4,5)P2-rich domain. Accordingly, we identified an FFAT site at the TRPC3 N-terminal loop within the linker helices that envelope the C-terminus pole helix. The FFAT site interacts with the ER-resident VAPB to recruit TRPC3 to the ER/PM junctions and control its receptor-mediated activation. The TRPC3’s lipid interacting sites are fully conserved in TRPC6 and TRPC7 and in part in other TRPC channels. These findings inform on multiple modes of regulation of ion channels by lipids that may be relevant to diseases affected by aberrant TRPC channel functions.
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Affiliation(s)
- Haiping Liu
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Wei-Yin Lin
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Spencer R Leibow
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Alexander J Morateck
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD
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7
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Jain PP, Lai N, Xiong M, Chen J, Babicheva A, Zhao T, Parmisano S, Zhao M, Paquin C, Matti M, Powers R, Balistrieri A, Kim NH, Valdez-Jasso D, Thistlethwaite PA, Shyy JYJ, Wang J, Garcia JGN, Makino A, Yuan JXJ. TRPC6, a therapeutic target for pulmonary hypertension. Am J Physiol Lung Cell Mol Physiol 2021; 321:L1161-L1182. [PMID: 34704831 PMCID: PMC8715021 DOI: 10.1152/ajplung.00159.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/20/2022] Open
Abstract
Idiopathic pulmonary arterial hypertension (PAH) is a fatal and progressive disease. Sustained vasoconstriction due to pulmonary arterial smooth muscle cell (PASMC) contraction and concentric arterial remodeling due partially to PASMC proliferation are the major causes for increased pulmonary vascular resistance and increased pulmonary arterial pressure in patients with precapillary pulmonary hypertension (PH) including PAH and PH due to respiratory diseases or hypoxemia. We and others observed upregulation of TRPC6 channels in PASMCs from patients with PAH. A rise in cytosolic Ca2+ concentration ([Ca2+]cyt) in PASMC triggers PASMC contraction and vasoconstriction, while Ca2+-dependent activation of PI3K/AKT/mTOR pathway is a pivotal signaling cascade for cell proliferation and gene expression. Despite evidence supporting a pathological role of TRPC6, no selective and orally bioavailable TRPC6 antagonist has yet been developed and tested for treatment of PAH or PH. In this study, we sought to investigate whether block of receptor-operated Ca2+ channels using a nonselective blocker of cation channels, 2-aminoethyl diphenylborinate (2-APB, administered intraperitoneally) and a selective blocker of TRPC6, BI-749327 (administered orally) can reverse established PH in mice. The results from the study show that intrapulmonary application of 2-APB (40 µM) or BI-749327 (3-10 µM) significantly and reversibly inhibited acute alveolar hypoxia-induced pulmonary vasoconstriction. Intraperitoneal injection of 2-APB (1 mg/kg per day) significantly attenuated the development of PH and partially reversed established PH in mice. Oral gavage of BI-749327 (30 mg/kg, every day, for 2 wk) reversed established PH by ∼50% via regression of pulmonary vascular remodeling. Furthermore, 2-APB and BI-749327 both significantly inhibited PDGF- and serum-mediated phosphorylation of AKT and mTOR in PASMC. In summary, the receptor-operated and mechanosensitive TRPC6 channel is a good target for developing novel treatment for PAH/PH. BI-749327, a selective TRPC6 blocker, is potentially a novel and effective drug for treating PAH and PH due to respiratory diseases or hypoxemia.
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MESH Headings
- Animals
- Boron Compounds/pharmacology
- Calcium Signaling
- Cells, Cultured
- Gene Expression Regulation/drug effects
- Humans
- Hypertension, Pulmonary/drug therapy
- Hypertension, Pulmonary/metabolism
- Hypertension, Pulmonary/pathology
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Phosphatidylinositol 3-Kinases/genetics
- Phosphatidylinositol 3-Kinases/metabolism
- Pulmonary Artery/drug effects
- Pulmonary Artery/metabolism
- Pulmonary Artery/pathology
- TOR Serine-Threonine Kinases/genetics
- TOR Serine-Threonine Kinases/metabolism
- TRPC6 Cation Channel/antagonists & inhibitors
- TRPC6 Cation Channel/genetics
- TRPC6 Cation Channel/metabolism
- Vasoconstriction
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Affiliation(s)
- Pritesh P Jain
- Section of Physiology, University of California, San Diego, La Jolla, California
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Ning Lai
- Section of Physiology, University of California, San Diego, La Jolla, California
- State Key Laboratory of Respiratory Medicine and First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Mingmei Xiong
- Section of Physiology, University of California, San Diego, La Jolla, California
- State Key Laboratory of Respiratory Medicine and First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jiyuan Chen
- Section of Physiology, University of California, San Diego, La Jolla, California
- State Key Laboratory of Respiratory Medicine and First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Aleksandra Babicheva
- Section of Physiology, University of California, San Diego, La Jolla, California
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Tengteng Zhao
- Section of Physiology, University of California, San Diego, La Jolla, California
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Sophia Parmisano
- Section of Physiology, University of California, San Diego, La Jolla, California
| | - Manjia Zhao
- Section of Physiology, University of California, San Diego, La Jolla, California
| | - Cole Paquin
- Section of Physiology, University of California, San Diego, La Jolla, California
| | - Moreen Matti
- Section of Physiology, University of California, San Diego, La Jolla, California
| | - Ryan Powers
- Section of Physiology, University of California, San Diego, La Jolla, California
| | - Angela Balistrieri
- Section of Physiology, University of California, San Diego, La Jolla, California
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Nick H Kim
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
| | - Daniela Valdez-Jasso
- Department of Bioengineering, University of California, San Diego, La Jolla, California
| | - Patricia A Thistlethwaite
- Division of Cardiothoracic Surgery, Department of Surgery, University of California, San Diego, La Jolla, California
| | - John Y-J Shyy
- Division of Cardiovascular Medicine, University of California, San Diego, La Jolla, California
| | - Jian Wang
- Section of Physiology, University of California, San Diego, La Jolla, California
- State Key Laboratory of Respiratory Medicine and First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Joe G N Garcia
- Department of Medicine, The University of Arizona, Tucson, Arizona
| | - Ayako Makino
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, California
| | - Jason X-J Yuan
- Section of Physiology, University of California, San Diego, La Jolla, California
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, La Jolla, California
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8
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Fang X, Dong S, Wu Y, He Y, Lu M, Shi D, Feng N, Yin S, Jiang Y, Zhang A, Ding Y, Zhang Q, Tang J, Zhang W, He X. Ameliorated biomechanical properties of carotid arteries by puerarin in spontaneously hypertensive rats. BMC Complement Med Ther 2021; 21:173. [PMID: 34154575 PMCID: PMC8216761 DOI: 10.1186/s12906-021-03345-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/02/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND An emerging body of evidence indicates that puerarin (PUE) plays an important role in the treatment of angina pectoris, myocardial ischemia-reperfusion injury, hypertension and other cardiovascular diseases, but how PUE affects the vascular remodeling of hypertensive rats has not been reported yet. This study aimed to investigate the effect and mechanism of PUE on carotid arteries of spontaneously hypertensive rats (SHR) to provide the basis for the clinical application of PUE. METHODS Thirty male SHR and six male Wistar Kyoto rats (WKY) aged 3 months were used in this study, SHR rats were randomly divided into 5 groups, PUE(40 or 80 mg/kg/d, ip) and telmisartan (TELMI) (30 mg/kg/d, ig) were administrated for 3 months. We use DMT myography pressure-diameter system to investigate biomechanical properties of carotid arteries, 10 μM pan-classical transient receptor potential channels (TRPCs) inhibitor SKF96365, 200 nM specific TRPC6 inhibitor SAR7334 and 100 μM Orai1 inhibitor ANCOA4 were used in the mechanical test. RESULTS PUE can significantly decrease systolic and diastolic blood pressure, long-term administration of PUE resulted in a mild reduction of thickness and inner diameter of carotid artery. PUE ameliorate NE-response and vascular remodeling mainly through inhibiting TRPCs channel activities of VSMC. CONCLUSION PUE can ameliorate biomechanical remodeling of carotid arteries through inhibiting TRPCs channel activities of VSMC in spontaneously hypertensive rats.
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Affiliation(s)
- Xiaoxia Fang
- Department of Neurology, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
| | - Sheng Dong
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
| | - Yun Wu
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
| | - Yun He
- Department of Ultrasound, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
| | - Min Lu
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, 442000 China
| | - Dandan Shi
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
| | - Na Feng
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
| | - Songhe Yin
- Department of Neurology, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
| | - Yan Jiang
- Department of Ultrasound, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
| | - Anhua Zhang
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
| | - Yan Ding
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, 442000 China
| | - Qiufang Zhang
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, 442000 China
| | - Junming Tang
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, 442000 China
| | - Wenjun Zhang
- Department of Ultrasound, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
| | - Xiju He
- Department of Anatomy, Hubei University of Medicine, Shiyan, 442000 China
- Department of Ultrasound, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000 China
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, 442000 China
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9
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Kawanabe A, Mizutani N, Polat OK, Yonezawa T, Kawai T, Mori MX, Okamura Y. Engineering an enhanced voltage-sensing phosphatase. J Gen Physiol 2021; 152:133870. [PMID: 32167537 PMCID: PMC7201886 DOI: 10.1085/jgp.201912491] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/05/2019] [Accepted: 02/16/2020] [Indexed: 01/11/2023] Open
Abstract
Voltage-sensing phosphatases (VSP) consist of a membrane-spanning voltage sensor domain and a cytoplasmic region that has enzymatic activity toward phosphoinositides (PIs). VSP enzyme activity is regulated by membrane potential, and its activation leads to rapid and reversible alteration of cellular PIP levels. These properties enable VSPs to be used as a tool for studying the effects of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) binding to ion channels and transporters. For example, by applying simple changes in the membrane potential, Danio rerio VSP (Dr-VSP) has been used effectively to manipulate PI(4,5)P2 in mammalian cells with few, if any, side effects. In the present study, we report an enhanced version of Dr-VSP as an improved molecular tool for depleting PI(4,5)P2 from cultured mammalian cells. We modified Dr-VSP in two ways. Its voltage-dependent phosphatase activity was enhanced by introducing an aromatic residue at the position of Leu-223 within a membrane-interacting region of the phosphatase domain called the hydrophobic spine. In addition, selective plasma membrane targeting of Dr-VSP was facilitated by fusion with the N-terminal region of Ciona intestinalis VSP. This modified Dr-VSP (CiDr-VSPmChe L223F, or what we call eVSP) induced more drastic voltage-evoked changes in PI(4,5)P2 levels, using the activities of Kir2.1, KCNQ2/3, and TRPC6 channels as functional readouts. eVSP is thus an improved molecular tool for evaluating the PI(4,5)P2 sensitivity of ion channels in living cells.
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Affiliation(s)
- Akira Kawanabe
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Natsuki Mizutani
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Onur K Polat
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Tomoko Yonezawa
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Takafumi Kawai
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Yasushi Okamura
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
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10
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Crul T, Maléth J. Endoplasmic Reticulum-Plasma Membrane Contact Sites as an Organizing Principle for Compartmentalized Calcium and cAMP Signaling. Int J Mol Sci 2021; 22:ijms22094703. [PMID: 33946838 PMCID: PMC8124356 DOI: 10.3390/ijms22094703] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 01/14/2023] Open
Abstract
In eukaryotic cells, ultimate specificity in activation and action-for example, by means of second messengers-of the myriad of signaling cascades is primordial. In fact, versatile and ubiquitous second messengers, such as calcium (Ca2+) and cyclic adenosine monophosphate (cAMP), regulate multiple-sometimes opposite-cellular functions in a specific spatiotemporal manner. Cells achieve this through segregation of the initiators and modulators to specific plasma membrane (PM) subdomains, such as lipid rafts and caveolae, as well as by dynamic close contacts between the endoplasmic reticulum (ER) membrane and other intracellular organelles, including the PM. Especially, these membrane contact sites (MCSs) are currently receiving a lot of attention as their large influence on cell signaling regulation and cell physiology is increasingly appreciated. Depletion of ER Ca2+ stores activates ER membrane STIM proteins, which activate PM-residing Orai and TRPC Ca2+ channels at ER-PM contact sites. Within the MCS, Ca2+ fluxes relay to cAMP signaling through highly interconnected networks. However, the precise mechanisms of MCS formation and the influence of their dynamic lipid environment on their functional maintenance are not completely understood. The current review aims to provide an overview of our current understanding and to identify open questions of the field.
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Affiliation(s)
- Tim Crul
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
- Correspondence: (T.C.); (J.M.)
| | - József Maléth
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
- Correspondence: (T.C.); (J.M.)
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11
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An Arrhythmic Mutation E7K Facilitates TRPM4 Channel Activation via Enhanced PIP 2 Interaction. Cells 2021; 10:cells10050983. [PMID: 33922380 PMCID: PMC8146980 DOI: 10.3390/cells10050983] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/16/2021] [Accepted: 04/21/2021] [Indexed: 11/17/2022] Open
Abstract
A Ca2+-activated monovalent cation-selective TRPM4 channel is abundantly expressed in the heart. Recently, a single gain-of-function mutation identified in the distal N-terminus of the human TRPM4 channel (Glu5 to Lys5; E7K) was found to be arrhythmogenic because of enhanced cell membrane expression. In this study, we conducted detailed analyses of this mutant channel from more functional aspects, in comparison with its wild type (WT). In an expression system, intracellular application of a short soluble PIP2 (diC8PIP2) restored the single-channel activities of both WT and E7K, which had quickly faded after membrane excision. The potency (Kd) of diC8PIP2 for this recovery was stronger in E7K than its WT (1.44 vs. 2.40 μM). FRET-based PIP2 measurements combined with the Danio rerio voltage-sensing phosphatase (DrVSP) and patch clamping revealed that lowering the endogenous PIP2 level by DrVSP activation reduced the TRPM4 channel activity. This effect was less prominent in E7K than its WT (apparent Kd values estimated from DrVSP-mediated PIP2 depletion: 0.97 and 1.06 μM, respectively), being associated with the differential PIP2-mediated modulation of voltage dependence. Moreover, intracellular perfusion of short N-terminal polypeptides containing either the ‘WT’ or ‘E7K’ sequences respectively attenuated the TRPM4 channel activation at whole-cell and single-channel levels, but in both configurations, the E7K polypeptide exerted greater inhibitory effects. These results collectively suggest that N-terminal interaction with endogenous PIP2 is essential for the TRPM4 channel to function, the extent of which may be abnormally strengthened by the E7K mutation through modulating voltage-dependent activation. The altered PIP2 interaction may account for the arrhythmogenic potential of this mutation.
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12
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Azuma YT, Suzuki S, Nishiyama K, Yamaguchi T. Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel. J Vet Med Sci 2021; 83:622-629. [PMID: 33583865 PMCID: PMC8111361 DOI: 10.1292/jvms.20-0490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Excessive stress response causes disability in social life. There are many diseases
caused by stress, such as gastrointestinal motility disorders, depression, eating
disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels
underlie non-selective cation currents and are downstream effectors of G protein-coupled
receptors. Ca2+ influx is important for smooth muscle contraction, which is
responsible for gastrointestinal motility. Little is known about the possible involvement
of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of
this study was to measure the changes in gastrointestinal motility caused by stress and to
elucidate the mechanism of these changes. The stress model used the water immersion
restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses
to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was
significantly reduced in the ileum of stressed mouse. Even under the conditions treated
with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed
mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced
contractions were all significantly reduced in the ileum of stressed mouse. Furthermore,
the expression of TRPC3 was decreased in the ileum of stressed mouse. These results
suggest that the gastrointestinal motility disorders due to stress is associated with
specific non-selective cation channel.
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Affiliation(s)
- Yasu-Taka Azuma
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Sho Suzuki
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Kazuhiro Nishiyama
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Taro Yamaguchi
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka 573-0101, Japan
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13
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Chen X, Sooch G, Demaree IS, White FA, Obukhov AG. Transient Receptor Potential Canonical (TRPC) Channels: Then and Now. Cells 2020; 9:E1983. [PMID: 32872338 PMCID: PMC7565274 DOI: 10.3390/cells9091983] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 12/13/2022] Open
Abstract
Twenty-five years ago, the first mammalian Transient Receptor Potential Canonical (TRPC) channel was cloned, opening the vast horizon of the TRPC field. Today, we know that there are seven TRPC channels (TRPC1-7). TRPCs exhibit the highest protein sequence similarity to the Drosophila melanogaster TRP channels. Similar to Drosophila TRPs, TRPCs are localized to the plasma membrane and are activated in a G-protein-coupled receptor-phospholipase C-dependent manner. TRPCs may also be stimulated in a store-operated manner, via receptor tyrosine kinases, or by lysophospholipids, hypoosmotic solutions, and mechanical stimuli. Activated TRPCs allow the influx of Ca2+ and monovalent alkali cations into the cytosol of cells, leading to cell depolarization and rising intracellular Ca2+ concentration. TRPCs are involved in the continually growing number of cell functions. Furthermore, mutations in the TRPC6 gene are associated with hereditary diseases, such as focal segmental glomerulosclerosis. The most important recent breakthrough in TRPC research was the solving of cryo-EM structures of TRPC3, TRPC4, TRPC5, and TRPC6. These structural data shed light on the molecular mechanisms underlying TRPCs' functional properties and propelled the development of new modulators of the channels. This review provides a historical overview of the major advances in the TRPC field focusing on the role of gene knockouts and pharmacological tools.
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Affiliation(s)
- Xingjuan Chen
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an 710072, China;
| | - Gagandeep Sooch
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
| | - Isaac S. Demaree
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
| | - Fletcher A. White
- The Department of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Alexander G. Obukhov
- The Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (G.S.); (I.S.D.)
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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14
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Martín-Aragón Baudel MAS, Shi J, Large WA, Albert AP. Obligatory role for PKCδ in PIP 2 -mediated activation of store-operated TRPC1 channels in vascular smooth muscle cells. J Physiol 2020; 598:3911-3925. [PMID: 32627185 PMCID: PMC7656825 DOI: 10.1113/jp279947] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/01/2020] [Indexed: 12/13/2022] Open
Abstract
KEY POINTS In vascular smooth muscle cells (VSMCs), activation of Ca2+ -permeable store-operated channels (SOCs) composed of canonical transient receptor potential channel 1 (TRPC1) subunits mediates Ca2+ entry pathways that regulate contraction, proliferation and migration, which are processes associated with vascular disease. Activation of TRPC1-based SOCs requires protein kinase C (PKC) activity, which is proposed to phosphorylate TRPC1 proteins to promote channel opening by phosphatidylinositol 4,5-bisphosphate (PIP2 ). We investigated the identity of the PKC isoform involved in activating TRPC1-based SOCs in rat mesenteric artery VSMCs. TRPC1-based SOCs were reduced by PKCδ inhibitors and knockdown of PKCδ expression. Store depletion induced interactions between TRPC1 and PKCδ and PKCδ-dependent phosphorylation of TRPC1. Furthermore, generation of store-operated interactions between PIP2 and TRPC1 and activation of TRPC1-based SOCs by PIP2 required PKCδ. These findings reveal that PKCδ activity has an obligatory role in activating TRPC1-based SOCs, through regulating PIP2 -mediated channel opening. ABSTRACT In vascular smooth muscle cells (VMSCs), stimulation of Ca2+ -permeable canonical transient receptor potential channel 1 (TRPC1)-based store-operated channels (SOCs) mediates Ca2+ entry pathways that regulate cell contraction, proliferation and migration, which are processes associated with vascular disease. It is therefore important to understand how TRPC1-based SOCs are activated. Stimulation of TRPC1-based SOCs requires protein kinase C (PKC) activity, with store-operated PKC-dependent phosphorylation of TRPC1 essential for channel opening by phosphatidylinositol 4,5-bisphosphate (PIP2 ). Experimental protocols used to activate TRPC1-based SOCs suggest that the PKC isoform involved requires diacylglycerol (DAG) but is Ca2+ -insensitive, which are characteristics of the novel group of PKC isoforms (δ, ε, η, θ). Hence, the present study examined whether a novel PKC isoform(s) is involved in activating TRPC1-based SOCs in contractile rat mesenteric artery VSMCs. Store-operated whole-cell cation currents were blocked by Pico145, a highly selective and potent TRPC1/4/5 channel blocker and T1E3, a TRPC1 blocking antibody. PKCδ was expressed in VSMCs, and selective PKCδ inhibitory peptides and knockdown of PKCδ expression with morpholinos oligomers inhibited TRPC1-based SOCs. TRPC1 and PKCδ interactions and phosphorylation of TRPC1 induced by store depletion were both reduced by pharmacological inhibition and PKCδ knockdown. In addition, store-operated PIP2 and TRPC1 interactions were blocked by PKCδ inhibition, and PKCδ was required for PIP2 -mediated activation of TRPC1 currents. These results identify the involvement of PKCδ in stimulation of TRPC1-based SOCs and highlight that store-operated PKCδ activity is obligatory for channel opening by PIP2 , the probable activating ligand.
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Affiliation(s)
| | - Jian Shi
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - William A Large
- Vascular Biology Research Centre, Molecular and Clinical Research Institute, St George's, University of London, Cranmer Terrace, London, UK
| | - Anthony P Albert
- Vascular Biology Research Centre, Molecular and Clinical Research Institute, St George's, University of London, Cranmer Terrace, London, UK
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15
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Jeon J, Tian JB, Zhu MX. TRPC4 as a coincident detector of G i/o and G q/11 signaling: mechanisms and pathophysiological implications. CURRENT OPINION IN PHYSIOLOGY 2020; 17:34-41. [PMID: 32851198 DOI: 10.1016/j.cophys.2020.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
TRPC channels are Ca2+-permeable nonselective cation channels activated downstream from phospholipase C (PLC). Although most TRPC channels can be activated by stimulating Gq/11-coupled receptors, TRPC4 requires simultaneous stimulation of Gi/o-coupled receptors, making it a perfect detector of coincident Gi/o and Gq/11 signaling. Evidence shows that activated Gαi/o proteins work together with PLCδ1 to induce robust TRPC4 activation and the process is accelerated by stimulation of other PLC isozymes, such as PLCβ through Gq/11 proteins. Mechanistically, Gq/11-PLCβ activation produces triggering proton and calcium signals to initiate self-propagating PLCδ1 activity, crucial for Gi/o-mediated TRPC4 function. Thus, TRPC4-containing channels are activated under conditions not only when coincident Gi/o and Gq/11 stimulation occurs, but also when Gi/o stimulation coincides with proton and Ca2+ signals. The resulting cytosolic Ca2+ rise and membrane depolarization switch the inhibitory Gi/o response to excitation. The conditions and implications of Gi/o-mediated TRPC4 activation in physiology and pathophysiology warrant further investigation.
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Affiliation(s)
- Jaepyo Jeon
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Jin-Bin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
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16
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Wang H, Cheng X, Tian J, Xiao Y, Tian T, Xu F, Hong X, Zhu MX. TRPC channels: Structure, function, regulation and recent advances in small molecular probes. Pharmacol Ther 2020; 209:107497. [PMID: 32004513 DOI: 10.1016/j.pharmthera.2020.107497] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/14/2020] [Indexed: 02/08/2023]
Abstract
Transient receptor potential canonical (TRPC) channels constitute a group of receptor-operated calcium-permeable nonselective cation channels of the TRP superfamily. The seven mammalian TRPC members, which can be further divided into four subgroups (TRPC1, TRPC2, TRPC4/5, and TRPC3/6/7) based on their amino acid sequences and functional similarities, contribute to a broad spectrum of cellular functions and physiological roles. Studies have revealed complexity of their regulation involving several components of the phospholipase C pathway, Gi and Go proteins, and internal Ca2+ stores. Recent advances in cryogenic electron microscopy have provided several high-resolution structures of TRPC channels. Growing evidence demonstrates the involvement of TRPC channels in diseases, particularly the link between genetic mutations of TRPC6 and familial focal segmental glomerulosclerosis. Because TRPCs were discovered by the molecular identity first, their pharmacology had lagged behind. This is rapidly changing in recent years owning to great efforts from both academia and industry. A number of potent tool compounds from both synthetic and natural products that selective target different subtypes of TRPC channels have been discovered, including some preclinical drug candidates. This review will cover recent advancements in the understanding of TRPC channel regulation, structure, and discovery of novel TRPC small molecular probes over the past few years, with the goal of facilitating drug discovery for the study of TRPCs and therapeutic development.
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Affiliation(s)
- Hongbo Wang
- Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education; Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai 264005, China.
| | - Xiaoding Cheng
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
| | - Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yuling Xiao
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China
| | - Tian Tian
- Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China
| | - Fuchun Xu
- Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China
| | - Xuechuan Hong
- State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (MOE) and Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Innovation Center for Traditional Tibetan Medicine Modernization and Quality Control, Medical College, Department of Chemistry and Environmental Science, School of Science, Tibet University, Lhasa 850000, China.
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
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17
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Martín-Aragón Baudel MAS, Shi J, Large WA, Albert AP. Insights into Activation Mechanisms of Store-Operated TRPC1 Channels in Vascular Smooth Muscle. Cells 2020; 9:E179. [PMID: 31936855 PMCID: PMC7017204 DOI: 10.3390/cells9010179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 01/10/2023] Open
Abstract
In vascular smooth muscle cells (VMSCs), the stimulation of store-operated channels (SOCs) mediate Ca2+ influx pathways which regulate important cellular functions including contraction, proliferation, migration, and growth that are associated with the development of vascular diseases. It is therefore important that we understand the biophysical, molecular composition, activation pathways, and physiological significance of SOCs in VSMCs as these maybe future therapeutic targets for conditions such as hypertension and atherosclerosis. Archetypal SOCs called calcium release-activated channels (CRACs) are composed of Orai1 proteins and are stimulated by the endo/sarcoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1) following store depletion. In contrast, this review focuses on proposals that canonical transient receptor potential (TRPC) channels composed of a heteromeric TRPC1/C5 molecular template, with TRPC1 conferring activation by store depletion, mediate SOCs in native contractile VSMCs. In particular, it summarizes our recent findings which describe a novel activation pathway of these TRPC1-based SOCs, in which protein kinase C (PKC)-dependent TRPC1 phosphorylation and phosphatidylinositol 4,5-bisphosphate (PIP2) are obligatory for channel opening. This PKC- and PIP2-mediated gating mechanism is regulated by the PIP2-binding protein myristoylated alanine-rich C kinase (MARCKS) and is coupled to store depletion by TRPC1-STIM1 interactions which induce Gq/PLCβ1 activity. Interestingly, the biophysical properties and activation mechanisms of TRPC1-based SOCs in native contractile VSMCs are unlikely to involve Orai1.
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Affiliation(s)
| | - Jian Shi
- LIGHT Laboratories, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK;
| | - William A. Large
- Vascular Biology Research Centre, Molecular and Clinical Research Institute, St. George’s, University of London, London SW17 0RE, UK;
| | - Anthony P. Albert
- Vascular Biology Research Centre, Molecular and Clinical Research Institute, St. George’s, University of London, London SW17 0RE, UK;
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18
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Ko J, Myeong J, Kwak M, Jeon JH, So I. Identification of phospholipase C β downstream effect on transient receptor potential canonical 1/4, transient receptor potential canonical 1/5 channels. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:357-366. [PMID: 31496873 PMCID: PMC6717798 DOI: 10.4196/kjpp.2019.23.5.357] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 12/21/2022]
Abstract
Gαq-coupled receptor stimulation was implied in the activation process of transient receptor potential canonical (TRPC)1/4 and TRPC1/5 heterotetrameric channels. The inactivation occurs due to phosphatidylinositol 4,5-biphosphate (PI(4,5)P2) depletion. When PI(4,5)P2 depletion was induced by muscarinic stimulation or inositol polyphosphate 5-phosphatase (Inp54p), however, the inactivation by muscarinic stimulation was greater compared to that by Inp54p. The aim of this study was to investigate the complete inactivation mechanism of the heteromeric channels upon Gαq-phospholipase C β (Gαq-PLCβ) activation. We evaluated the activity of heteromeric channels with electrophysiological recording in HEK293 cells expressing TRPC channels. TRPC1/4 and TRPC1/5 heteromers undergo further inhibition in PLCβ activation and calcium/protein kinase C (PKC) signaling. Nevertheless, the key factors differ. For TRPC1/4, the inactivation process was facilitated by Ca2+ release from the endoplasmic reticulum, and for TRPC1/5, activation of PKC was concerned mostly. We conclude that the subsequent increase in cytoplasmic Ca2+ due to Ca2+ release from the endoplasmic reticulum and activation of PKC resulted in a second phase of channel inhibition following PI(4,5)P2 depletion.
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Affiliation(s)
- Juyeon Ko
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jongyun Myeong
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea.,Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Misun Kwak
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Ju-Hong Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
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19
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Polat OK, Uno M, Maruyama T, Tran HN, Imamura K, Wong CF, Sakaguchi R, Ariyoshi M, Itsuki K, Ichikawa J, Morii T, Shirakawa M, Inoue R, Asanuma K, Reiser J, Tochio H, Mori Y, Mori MX. Contribution of Coiled-Coil Assembly to Ca 2+/Calmodulin-Dependent Inactivation of TRPC6 Channel and its Impacts on FSGS-Associated Phenotypes. J Am Soc Nephrol 2019; 30:1587-1603. [PMID: 31266820 DOI: 10.1681/asn.2018070756] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 04/23/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND TRPC6 is a nonselective cation channel, and mutations of this gene are associated with FSGS. These mutations are associated with TRPC6 current amplitude amplification and/or delay of the channel inactivation (gain-of-function phenotype). However, the mechanism of the gain-of-function in TRPC6 activity has not yet been clearly solved. METHODS We performed electrophysiologic, biochemical, and biophysical experiments to elucidate the molecular mechanism underlying calmodulin (CaM)-mediated Ca2+-dependent inactivation (CDI) of TRPC6. To address the pathophysiologic contribution of CDI, we assessed the actin filament organization in cultured mouse podocytes. RESULTS Both lobes of CaM helped induce CDI. Moreover, CaM binding to the TRPC6 CaM-binding domain (CBD) was Ca2+-dependent and exhibited a 1:2 (CaM/CBD) stoichiometry. The TRPC6 coiled-coil assembly, which brought two CBDs into adequate proximity, was essential for CDI. Deletion of the coiled-coil slowed CDI of TRPC6, indicating that the coiled-coil assembly configures both lobes of CaM binding on two CBDs to induce normal CDI. The FSGS-associated TRPC6 mutations within the coiled-coil severely delayed CDI and often increased TRPC6 current amplitudes. In cultured mouse podocytes, FSGS-associated channels and CaM mutations led to sustained Ca2+ elevations and a disorganized cytoskeleton. CONCLUSIONS The gain-of-function mechanism found in FSGS-causing mutations in TRPC6 can be explained by impairments of the CDI, caused by disruptions of TRPC's coiled-coil assembly which is essential for CaM binding. The resulting excess Ca2+ may contribute to structural damage in the podocytes.
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Affiliation(s)
- Onur K Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Masatoshi Uno
- Department of Biophysics, Graduate School of Science.,Department of Molecular Engineering, Graduate School of Engineering
| | - Terukazu Maruyama
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Ha Nam Tran
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Department of Technology and Ecology, Laboratory of Environmental Systems Biology, Graduate School of Global Environmental Studies
| | - Kayo Imamura
- Department of Biophysics, Graduate School of Science
| | - Chee Fah Wong
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Department of Biology, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Perak, Malaysia
| | - Reiko Sakaguchi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering.,Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan
| | - Mariko Ariyoshi
- Department of Molecular Engineering, Graduate School of Engineering
| | - Kyohei Itsuki
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Jun Ichikawa
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Takashi Morii
- Institute of Advanced Energy, Kyoto University, Kyoto, Japan
| | | | - Ryuji Inoue
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Katsuhiko Asanuma
- Department of Nephrology, School of Medicine, Chiba University, Chiba, Japan
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | | | - Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering
| | - Masayuki X Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering,
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20
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Ko J, Myeong J, Shin YC, So I. Differential PI(4,5)P 2 sensitivities of TRPC4, C5 homomeric and TRPC1/4, C1/5 heteromeric channels. Sci Rep 2019; 9:1849. [PMID: 30755645 PMCID: PMC6372716 DOI: 10.1038/s41598-018-38443-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/27/2018] [Indexed: 12/25/2022] Open
Abstract
Transient receptor potential canonical (TRPC) 4 and TRPC5 channels are modulated by the Gαq-PLC pathway. Since phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) maintains TRPC4 and TRPC5 channel function, the Gαq-PLC pathway inhibits channel activity by depleting PI(4,5)P2. Here we investigated the difference in PI(4,5)P2 sensitivity between homomeric and heteromeric TRPC channels. First, by using a Danio rerio voltage-sensing phosphatase (DrVSP), we show that PI(4,5)P2 dephosphorylation robustly inhibits TRPC4α, TRPC4β, and TRPC5 homotetramer currents and also TRPC1/4α, TRPC1/4β, and TRPC1/5 heterotetramer currents. Secondly, sensitivity of channels to PI(4,5)P2 dephosphorylation was suggested through the usage of FRET in combination with patch clamping. The sensitivity increased in the sequence TRPC4β < TRPC4α < TRPC5 in homotetramers, whereas when forming heterotetramers with TRPC1, the sensitivity was approximately equal between the channels. Thirdly, we determined putative PI(4,5)P2 binding sites based on a TRPC4 prediction model. By neutralization of basic residues, we identified putative PI(4,5)P2 binding sites because the mutations reduced FRET to a PI(4,5)P2 sensor and reduced the current amplitude. Therefore, one functional TRPC4 has 8 pockets with the two main binding regions; K419, K664/R511, K518, H630. We conclude that TRPC1 channel function as a regulator in setting PI(4,5)P2 affinity for TRPC4 and TRPC5 that changes PI(4,5)P2 sensitivity.
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Affiliation(s)
- Juyeon Ko
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jongyun Myeong
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.,Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Young-Cheul Shin
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
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21
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Okamura Y, Kawanabe A, Kawai T. Voltage-Sensing Phosphatases: Biophysics, Physiology, and Molecular Engineering. Physiol Rev 2019; 98:2097-2131. [PMID: 30067160 DOI: 10.1152/physrev.00056.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-sensing phosphatase (VSP) contains a voltage sensor domain (VSD) similar to that in voltage-gated ion channels, and a phosphoinositide phosphatase region similar to phosphatase and tensin homolog deleted on chromosome 10 (PTEN). The VSP gene is conserved from unicellular organisms to higher vertebrates. Membrane depolarization induces electrical driven conformational rearrangement in the VSD, which is translated into catalytic enzyme activity. Biophysical and structural characterization has revealed details of the mechanisms underlying the molecular functions of VSP. Coupling between the VSD and the enzyme is tight, such that enzyme activity is tuned in a graded fashion to the membrane voltage. Upon VSP activation, multiple species of phosphoinositides are simultaneously altered, and the profile of enzyme activity depends on the history of the membrane potential. VSPs have been the obvious candidate link between membrane potential and phosphoinositide regulation. However, patterns of voltage change regulating VSP in native cells remain largely unknown. This review addresses the current understanding of the biophysical biochemical properties of VSP and provides new insight into the proposed functions of VSP.
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Affiliation(s)
- Yasushi Okamura
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Akira Kawanabe
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Takafumi Kawai
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
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22
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Myeong J, Ko J, Kwak M, Kim J, Woo J, Ha K, Hong C, Yang D, Kim HJ, Jeon JH, So I. Dual action of the Gα q-PLCβ-PI(4,5)P 2 pathway on TRPC1/4 and TRPC1/5 heterotetramers. Sci Rep 2018; 8:12117. [PMID: 30108272 PMCID: PMC6092394 DOI: 10.1038/s41598-018-30625-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 08/03/2018] [Indexed: 11/09/2022] Open
Abstract
The transient receptor potential canonical (TRPC) 1 channel is widely distributed in mammalian cells and is involved in many physiological processes. TRPC1 is primarily considered a regulatory subunit that forms heterotetrameric channels with either TRPC4 or TRPC5 subunits. Here, we suggest that the regulation of TRPC1/4 and TRPC1/5 heterotetrameric channels by the Gαq-PLCβ pathway is self-limited and dynamically mediated by Gαq and PI(4,5)P2. We provide evidence indicating that Gαq protein directly interacts with either TRPC4 or TRPC5 of the heterotetrameric channels to permit activation. Simultaneously, Gαq-coupled PLCβ activation leads to the breakdown of PI(4,5)P2, which inhibits activity of TRPC1/4 and 1/5 channels.
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Affiliation(s)
- Jongyun Myeong
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.,Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Juyeon Ko
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Misun Kwak
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Jinsung Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Joohan Woo
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Kotdaji Ha
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Chansik Hong
- Department of Physiology, Chosun University School of Medicine, Kwangju, 61452, Republic of Korea
| | - Dongki Yang
- Department of Physiology, Gachon University College of Medicine, Incheon, 21936, Republic of Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
| | - Ju-Hong Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
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23
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Brini M, Leanza L, Szabo I. Lipid-Mediated Modulation of Intracellular Ion Channels and Redox State: Physiopathological Implications. Antioxid Redox Signal 2018; 28:949-972. [PMID: 28679281 DOI: 10.1089/ars.2017.7215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Significance: Ion channels play an important role in the regulation of organelle function within the cell, as proven by increasing evidence pointing to a link between altered function of intracellular ion channels and different pathologies ranging from cancer to neurodegenerative diseases, ischemic damage, and lysosomal storage diseases. Recent Advances: A link between these pathologies and redox state as well as lipid homeostasis and ion channel function is in the focus of current research. Critical Issues: Ion channels are target of modulation by lipids and lipid messengers, although in most cases the mechanistic details have not been clarified yet. Ion channel function importantly impacts production of reactive oxygen species (ROS), especially in the case of mitochondria and lysosomes. ROS, in turn, may modulate the function of intracellular channels triggering thereby a feedback control under physiological conditions. If produced in excess, ROS can be harmful to lipids and may produce oxidized forms of these membrane constituents that ultimately affect ion channel function by triggering a "circulus vitiosus." Future Directions: The present review summarizes our current knowledge about the contribution of intracellular channels to oxidative stress and gives examples of how these channels are modulated by lipids and how this modulation may affect ROS production in ROS-related diseases. Future studies need to address the importance of the regulation of intracellular ion channels and related oxidative stress by lipids in various physiological and pathological contexts. Antioxid. Redox Signal. 28, 949-972.
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Affiliation(s)
- Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
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24
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Zhang B, Liu B, Roos CM, Thompson MA, Prakash YS, Miller JD, Guo RW. TRPC6 and TRPC4 Heteromultimerization Mediates Store Depletion-Activated NCX1 Reversal in Proliferative Vascular Smooth Muscle Cells. Channels (Austin) 2018; 12:119-125. [PMID: 29560783 PMCID: PMC5972809 DOI: 10.1080/19336950.2018.1451696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Store depletion has been shown to induce Ca2+ entry by Na+/Ca+ exchange (NCX) 1 reversal in proliferative vascular smooth muscle cells (VSMCs). The study objective was to investigate the role of transient receptor potential canonical (TRPC) channels in store depletion and NCX1 reversal in proliferative VSMCs. In cultured VSMCs, expressing TRPC1, TRPC4, and TRPC6, the removal of extracellular Na+ was followed by a significant increase of cytosolic Ca2+ concentration that was inhibited by KBR, a selective NCX1 inhibitor. TRPC1 knockdown significantly suppressed store-operated, channel-mediated Ca2+ entry, but TRPC4 knockdown and TRPC6 knockdown had no effect. Separate knockdown of TRPC1, TRPC4, or TRPC6 did not have a significant effect on thapsigargin-initiated Na+ increase in the peripheral regions with KBR treatment, but knockdown of both TRPC4 and TRPC6 did. Stromal interaction molecule (STIM)1 knockdown significantly reduced TRPC4 and TRPC6 binding. The results demonstrated that TRPC4–TRPC6 heteromultimerization linked Ca2+ store depletion and STIM1 accumulation with NCX reversal in proliferative VSMCs.
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Affiliation(s)
- Bin Zhang
- a Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA; and Department of Physiology , Mayo Clinic , Rochester , MN , USA
| | - Bei Liu
- b Department of Obstetrics and Gynecology , Kunming General Hospital of Chengdu Military Command , Kunming , Yunnan , China
| | - Carolyn M Roos
- a Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA; and Department of Physiology , Mayo Clinic , Rochester , MN , USA
| | - Michael A Thompson
- c Department of Anesthesiology , Mayo Clinic , Rochester , Minnesota , USA
| | - Y S Prakash
- c Department of Anesthesiology , Mayo Clinic , Rochester , Minnesota , USA
| | - Jordan D Miller
- a Division of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA; and Department of Physiology , Mayo Clinic , Rochester , MN , USA
| | - Rui-Wei Guo
- d Department of Cardiology , Kunming General Hospital of Chengdu Military Command , Kunming , Yunnan , China
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25
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Lindström JB, Pierce NT, Latz MI. Role of TRP Channels in Dinoflagellate Mechanotransduction. THE BIOLOGICAL BULLETIN 2017; 233:151-167. [PMID: 29373067 DOI: 10.1086/695421] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transient receptor potential (TRP) ion channels are common components of mechanosensing pathways, mainly described in mammals and other multicellular organisms. To gain insight into the evolutionary origins of eukaryotic mechanosensory proteins, we investigated the involvement of TRP channels in mechanosensing in a unicellular eukaryotic protist, the dinoflagellate Lingulodinium polyedra. BLASTP analysis of the protein sequences predicted from the L. polyedra transcriptome revealed six sequences with high similarity to human TRPM2, TRPM8, TRPML2, TRPP1, and TRPP2; and characteristic TRP domains were identified in all sequences. In a phylogenetic tree including all mammalian TRP subfamilies and TRP channel sequences from unicellular and multicellular organisms, the L. polyedra sequences grouped with the TRPM, TPPML, and TRPP clades. In pharmacological experiments, we used the intrinsic bioluminescence of L. polyedra as a reporter of mechanoresponsivity. Capsaicin and RN1734, agonists of mammalian TRPV, and arachidonic acid, an agonist of mammalian TRPV, TRPA, TRPM, and Drosophila TRP, all stimulated bioluminescence in L. polyedra. Mechanical stimulation of bioluminescence, but not capsaicin-stimulated bioluminescence, was inhibited by gadolinium (Gd3+), a general inhibitor of mechanosensitive ion channels, and the phospholipase C (PLC) inhibitor U73122. These pharmacological results are consistent with the involvement of TRP-like channels in mechanosensing by L. polyedra. The TRP channels do not appear to be mechanoreceptors but rather are components of the mechanotransduction signaling pathway and may be activated via a PLC-dependent mechanism. The presence and function of TRP channels in a dinoflagellate emphasize the evolutionary conservation of both the channel structures and their functions.
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Key Words
- AA, amino acids
- AMTB hydrochloride, N-(3-Aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)benzamide hydrochloride
- Ce, Caenorhabditis elegans
- Cr, Chlamydomonas reinhardtii
- DMSO, dimethyl sulfoxide
- Dm, Drosophila melanogaster
- Dr, Danio rerio
- FSW, filtered seawater
- Gd3+, gadolinium
- GsMTx4, Grammostola spatulata mechanotoxin 4
- HC067047, 2-Methyl-1-[3-(4-morpholinyl)propyl]-5-phenyl-N-[3-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide
- HMM, Hidden Markov Model
- Hs, Homo sapiens
- Lp, Lingulodinium polyedra
- ML204, 4-Methyl-2-(1-piperidinyl)-quinoline
- Mb, Monosiga brevicollis
- ORF, open reading frame
- PIP2, Phosphatidylinositol 4,5-bisphosphate
- PLC, phospholipase C
- Pt, Paramecium tetraurelia
- RHC80267, O,O′-[1,6-Hexanediylbis(iminocarbonyl)]dioxime cyclohexanone
- RN1734, 2,4-Dichloro-N-isopropyl-N-(2-isopropylaminoethyl)benzenesulfonamide
- RN1747, 1-(4-Chloro-2-nitrophenyl)sulfonyl-4-benzylpiperazine
- TMHMM, transmembrane helix prediction
- TRP, transient receptor potential channel
- U73122, 1-[6-[((17β)-3-Methoxyestra-1,3,5[10]-trien-17-yl)amino]hexyl]-1H-pyrrole-2,5-dione
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26
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Ta CM, Acheson KE, Rorsman NJG, Jongkind RC, Tammaro P. Contrasting effects of phosphatidylinositol 4,5-bisphosphate on cloned TMEM16A and TMEM16B channels. Br J Pharmacol 2017; 174:2984-2999. [PMID: 28616863 PMCID: PMC5573538 DOI: 10.1111/bph.13913] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 12/19/2022] Open
Abstract
Background and Purpose Ca2+‐activated Cl− channels (CaCCs) are gated open by a rise in intracellular Ca2+ concentration ([Ca2+]i), typically provoked by activation of Gq‐protein coupled receptors (GqPCR). GqPCR activation initiates depletion of plasmalemmal phosphatidylinositol 4,5‐bisphosphate (PIP2). Here, we determined whether PIP2 acts as a signalling lipid for CaCCs coded by the TMEM16A and TMEM16B genes. Experimental Approach Patch‐clamp electrophysiology, in conjunction with genetically encoded systems to control cellular PIP2 content, was used to define the mechanism of action of PIP2 on TMEM16A and TMEM16B channels. Key Results A water‐soluble PIP2 analogue (diC8‐PIP2) activated TMEM16A channels by up to fivefold and inhibited TMEM16B by ~0.2‐fold. The effects of diC8‐PIP2 on TMEM16A currents were especially pronounced at low [Ca2+]i. In contrast, diC8‐PIP2 modulation of TMEM16B channels did not vary over a broad [Ca2+]i range but was only detectable at highly depolarized membrane potentials. Modulation of TMEM16A and TMEM16B currents was due to changes in channel gating, while single channel conductance was unaltered. Co‐expression of TMEM16A or TMEM16B with a Danio rerio voltage‐sensitive phosphatase (DrVSP), which degrades PIP2, led to reduction and enhancement of TMEM16A and TMEM16B currents respectively. These effects were abolished by an inactivating mutation in DrVSP and antagonized by simultaneous co‐expression of a phosphatidylinositol‐4‐phosphate 5‐kinase that catalyses PIP2 formation. Conclusions and Implications PIP2 acts as a modifier of TMEM16A and TMEM16B channel gating. Drugs interacting with PIP2 signalling may affect TMEM16A and TMEM16B channel gating and have potential uses in basic science and implications for therapy.
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Affiliation(s)
- Chau M Ta
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Nils J G Rorsman
- Department of Pharmacology, University of Oxford, Oxford, UK.,OXION Wellcome Trust Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
| | | | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Oxford, UK.,OXION Wellcome Trust Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
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27
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Alonso-Carbajo L, Kecskes M, Jacobs G, Pironet A, Syam N, Talavera K, Vennekens R. Muscling in on TRP channels in vascular smooth muscle cells and cardiomyocytes. Cell Calcium 2017; 66:48-61. [PMID: 28807149 DOI: 10.1016/j.ceca.2017.06.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 02/07/2023]
Abstract
The human TRP protein family comprises a family of 27 cation channels with diverse permeation and gating properties. The common theme is that they are very important regulators of intracellular Ca2+ signaling in diverse cell types, either by providing a Ca2+ influx pathway, or by depolarising the membrane potential, which on one hand triggers the activation of voltage-gated Ca2+ channels, and on the other limits the driving force for Ca2+ entry. Here we focus on the role of these TRP channels in vascular smooth muscle and cardiac striated muscle. We give an overview of highlights from the recent literature, and highlight the important and diverse roles of TRP channels in the pathophysiology of the cardiovascular system. The discovery of the superfamily of Transient Receptor Potential (TRP) channels has significantly enhanced our knowledge of multiple signal transduction mechanisms in cardiac muscle and vascular smooth muscle cells (VSMC). In recent years, multiple studies have provided evidence for the involvement of these channels, not only in the regulation of contraction, but also in cell proliferation and remodeling in pathological conditions. The mammalian family of TRP cation channels is composed by 28 genes which can be divided into 6 subfamilies groups based on sequence similarity: TRPC (Canonical), TRPM (Melastatin), TRPML (Mucolipins), TRPV (Vanilloid), TRPP (Policystin) and TRPA (Ankyrin-rich protein). Functional TRP channels are believed to form four-unit complexes in the plasma, each of them expressed with six transmembrane domain and intracellular N and C termini. Here we review the current knowledge on the expression of TRP channels in both muscle types, and discuss their functional properties and role in physiological and pathophysiological processes.
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Affiliation(s)
- Lucía Alonso-Carbajo
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Miklos Kecskes
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Griet Jacobs
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Andy Pironet
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Ninda Syam
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Karel Talavera
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium.
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, TRP Research Platform Leuven (TRPLe), Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium.
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28
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STIM-TRP Pathways and Microdomain Organization: Ca 2+ Influx Channels: The Orai-STIM1-TRPC Complexes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:139-157. [PMID: 28900913 DOI: 10.1007/978-3-319-57732-6_8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ca2+ influx by plasma membrane Ca2+ channels is the crucial component of the receptor-evoked Ca2+ signal. The two main Ca2+ influx channels of non-excitable cells are the Orai and TRPC families of Ca2+ channels. These channels are activated in response to cell stimulation and Ca2+ release from the endoplasmic reticulum (ER). The protein that conveys the Ca2+ content of the ER to the plasma membrane is the ER Ca2+ sensor STIM1. STIM1 activates the Orai channels and is obligatory for channel opening. TRPC channels can function in two modes, as STIM1-dependent and STIM1-independent. When activated by STIM1, both channel types function at the ER/PM (plasma membrane) junctions. This chapter describes the properties and regulation of the channels by STIM1, with emphasis how and when TRPC channels function as STIM1-dependent and STIM1-independent modes and their unique Ca2+-dependent physiological functions that are not shared with the Orai channels.
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29
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Rohacs T. Phosphoinositide signaling in somatosensory neurons. Adv Biol Regul 2016; 61:2-16. [PMID: 26724974 PMCID: PMC4884561 DOI: 10.1016/j.jbior.2015.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/06/2015] [Accepted: 11/07/2015] [Indexed: 02/03/2023]
Abstract
Somatosensory neurons of the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are responsible for detecting thermal and tactile stimuli. They are also the primary neurons mediating pain and itch. A large number of cell surface receptors in these neurons couple to phospholipase C (PLC) enzymes leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the generation of downstream signaling molecules. These neurons also express many different ion channels, several of which are regulated by phosphoinositides. This review will summarize the knowledge on phosphoinositide signaling in DRG neurons, with special focus on effects on sensory and other ion channels.
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Affiliation(s)
- Tibor Rohacs
- Rutgers, New Jersey Medical School, Newark, NJ, USA.
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30
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Critical roles of Gi/o proteins and phospholipase C-δ1 in the activation of receptor-operated TRPC4 channels. Proc Natl Acad Sci U S A 2016; 113:1092-7. [PMID: 26755577 DOI: 10.1073/pnas.1522294113] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Transient Receptor Potential Canonical (TRPC) proteins form nonselective cation channels commonly known to be activated downstream from receptors that signal through phospholipase C (PLC). Although TRPC3/C6/C7 can be directly activated by diacylglycerols produced by PLC breakdown of phosphatidylinositol 4,5-bisphosphate (PIP2), the mechanism by which the PLC pathway activates TRPC4/C5 remains unclear. We show here that TRPC4 activation requires coincident stimulation of Gi/o subgroup of G proteins and PLCδ, with a preference for PLCδ1 over PLCδ3, but not necessarily the PLCβ pathway commonly thought to be involved in receptor-operated TRPC activation. In HEK293 cells coexpressing TRPC4 and Gi/o-coupled µ opioid receptor, µ agonist elicited currents biphasically, with an initial slow phase preceding a rapidly developing phase. The currents were dependent on intracellular Ca(2+) and PIP2. Reducing PIP2 through phosphatases abolished the biphasic kinetics and increased the probability of channel activation by weak Gi/o stimulation. In both HEK293 cells heterologously expressing TRPC4 and renal carcinoma-derived A-498 cells endogenously expressing TRPC4, channel activation was inhibited by knocking down PLCδ1 levels and almost completely eliminated by a dominant-negative PLCδ1 mutant and a constitutively active RhoA mutant. Conversely, the slow phase of Gi/o-mediated TRPC4 activation was diminished by inhibiting RhoA or enhancing PLCδ function. Our data reveal an integrative mechanism of TRPC4 on detection of coincident Gi/o, Ca(2+), and PLC signaling, which is further modulated by the small GTPase RhoA. This mechanism is not shared with the closely related TRPC5, implicating unique roles of TRPC4 in signal integration in brain and other systems.
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31
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Transient Receptor Potential Canonical 7 (TRPC7), a Calcium (Ca(2+)) Permeable Non-selective Cation Channel. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:251-64. [PMID: 27161232 DOI: 10.1007/978-3-319-26974-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transient receptor potential canonical subfamily, member 7 (TRPC7) is the most recently identified member of the TRPC family of Ca(2+)-permeable non-selective cation channels. The gene encoding the TRPC7 channel plasma membrane protein was first cloned from mouse brain. TRPC7 mRNA and protein have been detected in cell types derived from multiple organ systems from various species including humans. Gq-coupled protein receptor activation is the predominant mode of TRPC7 activation. Lipid metabolites involved in the phospholipase C (PLC) signaling pathway, including diacylglycerol (DAG) and its precursor the phosphatidylinositol-4,5-bisphosphate (PIP2), have been shown to be direct regulators of TRPC7 channel. TRPC7 channels have been linked to the regulation of various cellular functions however, the depth of our understanding of TRPC7 channel function and regulation is limited in comparison to other TRP channel family members. This review takes a historical look at our current knowledge of TRPC7 mechanisms of activation and its role in cellular physiology and pathophysiology.
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32
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Rohacs T. Phosphoinositide regulation of TRPV1 revisited. Pflugers Arch 2015; 467:1851-69. [PMID: 25754030 PMCID: PMC4537841 DOI: 10.1007/s00424-015-1695-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/12/2015] [Accepted: 02/16/2015] [Indexed: 01/22/2023]
Abstract
The heat- and capsaicin-sensitive transient receptor potential vanilloid 1 ion channel (TRPV1) is regulated by plasma membrane phosphoinositides. The effects of these lipids on this channel have been controversial. Recent articles re-ignited the debate and also offered resolution to place some of the data in a coherent picture. This review summarizes the literature on this topic and provides a detailed and critical discussion on the experimental evidence for the various effects of phosphatidylinositol 4,5-bisphosphayte [PI(4,5)P2 or PIP2] on TRPV1. We conclude that PI(4,5)P2 and potentially its precursor PI(4)P are positive cofactors for TRPV1, acting via direct interaction with the channel, and their depletion by Ca(2+)-induced activation of phospholipase Cδ isoforms (PLCδ) limits channel activity during capsaicin-induced desensitization. Other negatively charged lipids at higher concentrations can also support channel activity, which may explain some controversies in the literature. PI(4,5)P2 also partially inhibits channel activity in some experimental settings, and relief from this inhibition upon PLCβ activation may contribute to sensitization. The negative effect of PI(4,5)P2 is more controversial and its mechanism is less well understood. Other TRP channels from the TRPV and TRPC families may also undergo similar dual regulation by phosphoinositides, thus the complexity of TRPV1 regulation is not unique to this channel.
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Affiliation(s)
- Tibor Rohacs
- Department of Pharmacology and Physiology Rutgers, New Jersey Medical School, 185 South Orange Ave, Newark, NJ, USA,
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Lopez E, Berna-Erro A, Salido GM, Rosado JA, Redondo PC. FKBP25 and FKBP38 regulate non-capacitative calcium entry through TRPC6. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2684-96. [PMID: 26239116 DOI: 10.1016/j.bbamcr.2015.07.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 07/27/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
Abstract
Non-capacitative calcium entry (NCCE) contributes to cell activation in response to the occupation of G protein-coupled membrane receptors. Thrombin administration to platelets evokes the synthesis of diacylglycerol downstream of PAR receptor activation. Diacylglycerol evokes NCCE through activating TRPC3 and TRPC6 in human platelets. Although it is known that immunophilins interact with TRPCs, the role of immunophilins in the regulation of NCCE remains unknown. Platelet incubation with FK506, an immunophilin antagonist, reduced OAG-evoked NCCE in a concentration-dependent manner, an effect that was independent on the inactivation of calcineurin (CaN). FK506 was unable to reduce NCCE evoked by OAG in platelets from TRPC6-/- mice. In HEK-293 cells overexpressing TRPC6, currents through TRPC6 were altered in the presence of FK506. We have found interaction between FKBP38 and other FKBPs, like FKBP25, FKBP12, and FKBP52 that were not affected by FK506, as well as with calmodulin (CaM). FK506 modified the pattern of association between FKBP25 and TRPCs as well as impaired OAG-evoked TRPC3 and TRPC6 coupling in both human and mouse platelets. By performing biotinylation experiments we have elucidated that FKBP25 and FKBP38 might be found at different cellular location, the plasma membrane and the already described intracellular locations. Finally, FKBP25 and FKBP38 silencing significantly inhibits OAG-evoked NCCE in MEG-01 and HEK293 cells, while overexpression of FKBP38 does not modify NCCE in HEK293 cells. All together, these findings provide strong evidence for a role of immunophilins, including FKBP25 and FKBP38, in NCCE mediated by TRPC6.
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Affiliation(s)
- Esther Lopez
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Alejandro Berna-Erro
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Gines M Salido
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Pedro C Redondo
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain.
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Rjasanow A, Leitner MG, Thallmair V, Halaszovich CR, Oliver D. Ion channel regulation by phosphoinositides analyzed with VSPs-PI(4,5)P2 affinity, phosphoinositide selectivity, and PI(4,5)P2 pool accessibility. Front Pharmacol 2015; 6:127. [PMID: 26150791 PMCID: PMC4472987 DOI: 10.3389/fphar.2015.00127] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 06/05/2015] [Indexed: 11/13/2022] Open
Abstract
The activity of many proteins depends on the phosphoinositide (PI) content of the membrane. E.g., dynamic changes of the concentration of PI(4,5)P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5)P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids. Voltage-sensitive phosphatases (VSPs) turn over PI(4,5)P2 to PI(4)P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5)P2. Because cellular PI(4,5)P2 is resynthesized rapidly, steady state PI(4,5)P2 changes with the degree of VSP activation and thus depends on membrane potential. Here we show that titration of endogenous PI(4,5)P2 with Ci-VSP allows for the quantification of relative PI(4,5)P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K+ channels to Ci-VSP allowed for comparison of PI(4,5)P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5)P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5)P2 and PI(4)P was insensitive to VSP. Surprisingly, despite comparable PI(4,5)P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5)P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5)P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5)P2 that differ in their accessibility to PLC and VSPs.
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Affiliation(s)
- Alexandra Rjasanow
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Germany ; Institute of Physiology, University of Freiburg Freiburg, Germany
| | - Michael G Leitner
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Germany
| | - Veronika Thallmair
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Germany
| | - Christian R Halaszovich
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Germany
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University Marburg, Germany
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Earley S, Brayden JE. Transient receptor potential channels in the vasculature. Physiol Rev 2015; 95:645-90. [PMID: 25834234 DOI: 10.1152/physrev.00026.2014] [Citation(s) in RCA: 295] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca(2+) levels or subcellular Ca(2+) signaling events. In addition to directly mediating Ca(2+) entry, TRP channels influence intracellular Ca(2+) dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions.
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Affiliation(s)
- Scott Earley
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
| | - Joseph E Brayden
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada; and Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont
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Hille B, Dickson EJ, Kruse M, Vivas O, Suh BC. Phosphoinositides regulate ion channels. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:844-56. [PMID: 25241941 PMCID: PMC4364932 DOI: 10.1016/j.bbalip.2014.09.010] [Citation(s) in RCA: 462] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 11/29/2022]
Abstract
Phosphoinositides serve as signature motifs for different cellular membranes and often are required for the function of membrane proteins. Here, we summarize clear evidence supporting the concept that many ion channels are regulated by membrane phosphoinositides. We describe tools used to test their dependence on phosphoinositides, especially phosphatidylinositol 4,5-bisphosphate, and consider mechanisms and biological meanings of phosphoinositide regulation of ion channels. This lipid regulation can underlie changes of channel activity and electrical excitability in response to receptors. Since different intracellular membranes have different lipid compositions, the activity of ion channels still in transit towards their final destination membrane may be suppressed until they reach an optimal lipid environment. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Bertil Hille
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA.
| | - Eamonn J Dickson
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA.
| | - Martin Kruse
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA.
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA.
| | - Byung-Chang Suh
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873, Republic of Korea.
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Dual depolarization responses generated within the same lateral septal neurons by TRPC4-containing channels. Pflugers Arch 2015; 466:1301-16. [PMID: 24121765 DOI: 10.1007/s00424-013-1362-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 10/26/2022]
Abstract
In the central nervous system, canonical transient receptor potential (TRPC) channels have been implicated in mediating neuronal excitation induced by stimulating metabotropic receptors, including group 1 metabotropic glutamate receptors (mGluRs). Lateral septal (LS) neurons express high levels of TRPC4 and group I mGluRs. However, to what extent native TRPC4-containing channels (TRPC4-cc) are activated as well as the impact of different levels of TRPC4-cc activation on neuronal excitability remain elusive. Here, we report that stimulating LS neurons with group I mGluR agonist, (S)-3,5-DHPG, causes either an immediate increase in firing rate or an initial burst followed by a pause of firing, which can be correlated with below-threshold-depolarization (BTD) or above-threshold-plateau-depolarization (ATPD), respectively, in whole-cell recordings. The early phase of BTD and the entire ATPD are completely absent in neurons from TRPC4−/− mice. Moreover, in the same LS neurons, BTD can be converted to ATPD at more depolarized potentials or with a brief current injection, suggesting that BTD and ATPD may represent partial and full activations of TRPC4-cc, respectively. We show that coincident mGluR stimulation and depolarization is required to evoke strong TRPC4-cc current, and Na+ and Ca2+ influx, together with dynamic changes of intracellular Ca(2+), are essential for ATPD induction. Our results suggest that TRPC4-cc integrates metabotropic receptor stimulation with intracellular Ca(2+) signals to generate two interconvertible depolarization responses to affect excitability of LS neurons in distinct fashions.
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Mori MX, Itsuki K, Hase H, Sawamura S, Kurokawa T, Mori Y, Inoue R. Dynamics of receptor-operated Ca(2+) currents through TRPC channels controlled via the PI(4,5)P2-PLC signaling pathway. Front Pharmacol 2015; 6:22. [PMID: 25717302 PMCID: PMC4324076 DOI: 10.3389/fphar.2015.00022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/24/2015] [Indexed: 12/02/2022] Open
Abstract
Transient receptor potential canonical (TRPC) channels are Ca2+-permeable, nonselective cation channels that carry receptor-operated Ca2+ currents (ROCs) triggered by receptor-induced, phospholipase C (PLC)-catalyzed hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Within the vasculature, TRPC channel ROCs contribute to smooth muscle cell depolarization, vasoconstriction, and vascular remodeling. However, TRPC channel ROCs exhibit a variable response to receptor-stimulation, and the regulatory mechanisms governing TRPC channel activity remain obscure. The variability of ROCs may be explained by their complex regulation by PI(4,5)P2 and its metabolites, which differentially affect TRPC channel activity. To resolve the complex regulation of ROCs, the use of voltage-sensing phosphoinositide phosphatases and model simulation have helped to reveal the time-dependent contribution of PI(4,5)P2 and the possible role of PI(4,5)P2 in the regulation of ROCs. These approaches may provide unprecedented insight into the dynamics of PI(4,5)P2 regulation of TRPC channels and the fundamental mechanisms underlying transmembrane ion flow. Within that context, we summarize the regulation of TRPC channels and their coupling to receptor-mediated signaling, as well as the application of voltage-sensing phosphoinositide phosphatases to this research. We also discuss the controversial bidirectional effects of PI(4,5)P2 using a model simulation that could explain the complicated effects of PI(4,5)P2 on different ROCs.
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Affiliation(s)
- Masayuki X Mori
- Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan
| | - Kyohei Itsuki
- Faculty of Dental Science, Kyushu University Fukuoka, Japan
| | - Hideharu Hase
- Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan
| | - Seishiro Sawamura
- Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan
| | - Tatsuki Kurokawa
- Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan
| | - Yasuo Mori
- Department of Synthetic and Biological Chemistry, School of Engineering, Kyoto University Kyoto, Japan
| | - Ryuji Inoue
- Department of Physiology, School of Medicine, Fukuoka University Fukuoka, Japan
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Fu J, Gao Z, Shen B, Zhu MX. Canonical transient receptor potential 4 and its small molecule modulators. SCIENCE CHINA-LIFE SCIENCES 2014; 58:39-47. [PMID: 25480324 DOI: 10.1007/s11427-014-4772-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 09/06/2014] [Indexed: 02/04/2023]
Abstract
Canonical transient receptor potential 4 (TRPC4) forms non-selective cation channels that contribute to phospholipase C-dependent Ca(2+) entry into cells following stimulation of G protein coupled receptors and receptor tyrosine kinases. Moreover, the channels are regulated by pertussis toxin-sensitive Gi/o proteins, lipids, and various other signaling mechanisms. TRPC4-containing channels participate in the regulation of a variety of physiological functions, including excitability of both gastrointestinal smooth muscles and brain neurons. This review is to present recent advances in the understanding of physiology and development of small molecular modulators of TRPC4 channels.
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Affiliation(s)
- Jie Fu
- Department of Physiology, Anhui Medical University, Hefei, 230032, China
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Abstract
Transient Receptor Potential (TRP) channels are activated by stimuli as diverse as heat, cold, noxious chemicals, mechanical forces, hormones, neurotransmitters, spices, and voltage. Besides their presumably similar general architecture, probably the only common factor regulating them is phosphoinositides. The regulation of TRP channels by phosphoinositides is complex. There are a large number of TRP channels where phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2 or PIP2] acts as a positive cofactor, similarly to many other ion channels. In several cases, however, PI(4,5)P2 inhibits TRP channel activity, sometimes even concurrently with the activating effect. This chapter will provide a comprehensive overview of the literature on regulation of TRP channels by membrane phosphoinositides.
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Mori MX, Inoue R. New experimental trends for phosphoinositides research on ion transporter/channel regulation. J Pharmacol Sci 2014; 126:186-97. [PMID: 25367262 DOI: 10.1254/jphs.14r14cp] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Phosphoinositides(4,5)-bisphosphates [PI(4,5)P2] critically controls membrane excitability, the disruption of which leads to pathophysiological states. PI(4,5)P2 plays a primary role in regulating the conduction and gating properties of ion channels/transporters, through electrostatic and hydrophobic interactions that allow direct associations. In recent years, the development of many molecular tools have brought deep insights into the mechanisms underlying PI(4,5)P2-mediated regulation. This review summarizes the methods currently available to manipulate the cell membrane PI(4,5)P2 level including pharmacological interventions as well as newly designed molecular tools. We concisely introduce materials and experimental designs suitable for the study of PI(4,5)P2-mediated regulation of ion-conducting molecules, in order to assist researchers who are interested in this area. It is our further hope that the knowledge introduced in this review will help to promote our understanding about the pathology of diseases such as cardiac arrhythmias, bipolar disorders, and Alzheimer's disease which are somehow associated with a disruption of PI(4,5)P2 metabolism.
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Affiliation(s)
- Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, School of Engineering, Kyoto University, Japan
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Itsuki K, Imai Y, Hase H, Okamura Y, Inoue R, Mori MX. PLC-mediated PI(4,5)P2 hydrolysis regulates activation and inactivation of TRPC6/7 channels. ACTA ACUST UNITED AC 2014; 143:183-201. [PMID: 24470487 PMCID: PMC4001779 DOI: 10.1085/jgp.201311033] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transient receptor potential classical (or canonical) (TRPC)3, TRPC6, and TRPC7 are a subfamily of TRPC channels activated by diacylglycerol (DAG) produced through the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) by phospholipase C (PLC). PI(4,5)P2 depletion by a heterologously expressed phosphatase inhibits TRPC3, TRPC6, and TRPC7 activity independently of DAG; however, the physiological role of PI(4,5)P2 reduction on channel activity remains unclear. We used Förster resonance energy transfer (FRET) to measure PI(4,5)P2 or DAG dynamics concurrently with TRPC6 or TRPC7 currents after agonist stimulation of receptors that couple to Gq and thereby activate PLC. Measurements made at different levels of receptor activation revealed a correlation between the kinetics of PI(4,5)P2 reduction and those of receptor-operated TRPC6 and TRPC7 current activation and inactivation. In contrast, DAG production correlated with channel activation but not inactivation; moreover, the time course of channel inactivation was unchanged in protein kinase C-insensitive mutants. These results suggest that inactivation of receptor-operated TRPC currents is primarily mediated by the dissociation of PI(4,5)P2. We determined the functional dissociation constant of PI(4,5)P2 to TRPC channels using FRET of the PLCδ Pleckstrin homology domain (PHd), which binds PI(4,5)P2, and used this constant to fit our experimental data to a model in which channel gating is controlled by PI(4,5)P2 and DAG. This model predicted similar FRET dynamics of the PHd to measured FRET in either human embryonic kidney cells or smooth muscle cells, whereas a model lacking PI(4,5)P2 regulation failed to reproduce the experimental data, confirming the inhibitory role of PI(4,5)P2 depletion on TRPC currents. Our model also explains various PLC-dependent characteristics of channel activity, including limitation of maximum open probability, shortening of the peak time, and the bell-shaped response of total current. In conclusion, our studies demonstrate a fundamental role for PI(4,5)P2 in regulating TRPC6 and TRPC7 activity triggered by PLC-coupled receptor stimulation.
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Affiliation(s)
- Kyohei Itsuki
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
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Hille B, Dickson E, Kruse M, Falkenburger B. Dynamic metabolic control of an ion channel. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 123:219-47. [PMID: 24560147 DOI: 10.1016/b978-0-12-397897-4.00008-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
G-protein-coupled receptors mediate responses to external stimuli in various cell types. We are interested in the modulation of KCNQ2/3 potassium channels by the Gq-coupled M1 muscarinic (acetylcholine) receptor (M1R). Here, we describe development of a mathematical model that incorporates all known steps along the M1R signaling cascade and accurately reproduces the macroscopic behavior we observe when KCNQ2/3 currents are inhibited following M1R activation. Gq protein-coupled receptors of the plasma membrane activate phospholipase C (PLC) which cleaves the minor plasma membrane lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) into the second messengers diacylgycerol and inositol 1,4,5-trisphosphate, leading to calcium release, protein kinase C (PKC) activation, and PI(4,5)P2 depletion. Combining optical and electrical techniques with knowledge of relative abundance of each signaling component has allowed us to develop a kinetic model and determine that (i) M1R activation and M1R/Gβ interaction are fast; (ii) Gαq/Gβ separation and Gαq/PLC interaction have intermediate time constants; (iii) the amount of activated PLC limits the rate of KCNQ2/3 suppression; (iv) weak PLC activation can elicit robust calcium signals without net PI(4,5)P2 depletion or KCNQ2/3 channel inhibition; and (v) depletion of PI(4,5)P2, and not calcium/CaM or PKC-mediated phosphorylation, closes KCNQ2/3 potassium channels, thereby increasing neuronal excitability.
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Affiliation(s)
- Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - Eamonn Dickson
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - Martin Kruse
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
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Zhang X, Trebak M. Transient receptor potential canonical 7: a diacylglycerol-activated non-selective cation channel. Handb Exp Pharmacol 2014; 222:189-204. [PMID: 24756707 DOI: 10.1007/978-3-642-54215-2_8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transient receptor potential canonical 7 (TRPC7) channel is the seventh member of the mammalian TRPC channel family. TRPC7 mRNA, protein, and channel activity have been detected in many tissues and organs from the mouse, rat, and human. TRPC7 has high sequence homology with TRPC3 and TRPC6, and all three channels are activated by membrane receptors that couple to isoforms of phospholipase C (PLC) and mediate non-selective cation currents. TRPC7, along with TRPC3 and TRPC6, can be activated by direct exogenous application of diacylglycerol (DAG) analogues and by pharmacological maneuvers that increase endogenous DAG in cells. TRPC7 shows distinct properties of activation, such as constitutive activity and susceptibility to negative regulation by extracellular Ca(2+) and by protein kinase C. TRPC7 can form heteromultimers with TRPC3 and TRPC6. Although TRPC7 remains one of the least studied TRPC channel, its role in various cell types and physiological and pathophysiological conditions is beginning to emerge.
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Affiliation(s)
- Xuexin Zhang
- Nanobioscience Constellation, The State University of New York (SUNY), College of Nanoscale Science and Engineering (CNSE), 257 Fuller Road, Albany, NY, 12203, USA
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Lukacs V, Rives JM, Sun X, Zakharian E, Rohacs T. Promiscuous activation of transient receptor potential vanilloid 1 (TRPV1) channels by negatively charged intracellular lipids: the key role of endogenous phosphoinositides in maintaining channel activity. J Biol Chem 2013; 288:35003-13. [PMID: 24158445 PMCID: PMC3853253 DOI: 10.1074/jbc.m113.520288] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 10/18/2013] [Indexed: 11/06/2022] Open
Abstract
The regulation of the heat- and capsaicin-activated transient receptor potential vanilloid 1 (TRPV1) channels by phosphoinositides is controversial. Data in cellular systems support the dependence of TRPV1 activity on phosphoinositides. The purified TRPV1, however, was recently shown to be fully functional in artificial liposomes in the absence of phosphoinositides. Here, we show that several other negatively charged phospholipids, including phosphatidylglycerol, can also support TRPV1 activity in excised patches at high concentrations. When we incorporated TRPV1 into planar lipid bilayers consisting of neutral lipids, capsaicin-induced activity depended on phosphatidylinositol 4,5-bisphosphate. We also found that TRPV1 activity in excised patches ran down and that MgATP reactivated the channel. Inhibition of phosphatidylinositol 4-kinases or enzymatic removal of phosphatidylinositol abolished this effect of MgATP, suggesting that it activated TRPV1 by generating endogenous phosphoinositides. We conclude that endogenous phosphoinositides are positive cofactors for TRPV1 activity. Our data highlight the importance of specificity in lipid regulation of ion channels and may reconcile discordant data obtained in various experimental settings.
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Affiliation(s)
- Viktor Lukacs
- From the Department of Pharmacology and Physiology, Rutgers New Jersey Medical School, Newark, New Jersey 07103 and
| | - Jan-Michael Rives
- From the Department of Pharmacology and Physiology, Rutgers New Jersey Medical School, Newark, New Jersey 07103 and
| | - Xiaohui Sun
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, Illinois 61605
| | - Eleonora Zakharian
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, Illinois 61605
| | - Tibor Rohacs
- From the Department of Pharmacology and Physiology, Rutgers New Jersey Medical School, Newark, New Jersey 07103 and
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Transient receptor potential canonical type 3 channels--their evolving role in hypertension and its related complications. J Cardiovasc Pharmacol 2013; 61:455-60. [PMID: 23364606 DOI: 10.1097/fjc.0b013e31828748a1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
: Recent studies indicate that transient receptor potential canonical type 3 (TRPC3) channels contribute to the regulation of blood pressure and vascular and renal function. Several studies show that TRPC3 dysfunction is associated with hypertension, atherosclerosis, cardiac hypertrophy, and cerebrovascular events. In this review, we summarize the role of TRPC3 channels in the cardiovascular system, and we focus on their pathophysiological role in hypertension and related target organ damages. We provide new insight into the involvement of TRPC3 channels in the development of hypertension and its related complications.
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Rohacs T. Regulation of transient receptor potential channels by the phospholipase C pathway. Adv Biol Regul 2013; 53:341-55. [PMID: 23916247 PMCID: PMC3805701 DOI: 10.1016/j.jbior.2013.07.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 07/01/2013] [Indexed: 11/21/2022]
Abstract
Transient Receptor Potential (TRP) channels were discovered while analyzing visual mutants in Drosophila. The protein encoded by the transient receptor potential (trp) gene is a Ca(2+) permeable cation channel activated downstream of the phospholipase C (PLC) pathway. While searching for homologs in other organisms, a surprisingly large number of mammalian TRP channels was cloned. The regulation of TRP channels is quite diverse, but many of them are either activated downstream of PLC, or modulated by it. This review will summarize the current knowledge on regulation of TRP channels by PLC, with special focus on TRPC-s, which can be considered as effectors of PLC and the heat- and capsaicin-sensitive TRPV1, which is modulated by the PLC pathway in a complex manner.
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Affiliation(s)
- Tibor Rohacs
- Rutgers, New Jersey Medical School, Newark, NJ, USA.
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Itsuki K, Imai Y, Okamura Y, Abe K, Inoue R, Mori MX. Voltage-sensing phosphatase reveals temporal regulation of TRPC3/C6/C7 channels by membrane phosphoinositides. Channels (Austin) 2012; 6:206-9. [PMID: 22760061 PMCID: PMC3431592 DOI: 10.4161/chan.20883] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
TRPC3/C6/C7 channels, a subgroup of classical/canonical TRP channels, are activated by
diacylglycerol produced via activation of phospholipase C (PLC)-coupled receptors.
Recognition of the physiological importance of these channels has been steadily growing,
but the mechanism by which they are regulated remains largely unknown. We recently used a
membrane-resident danio rerio voltage-sensing phosphatase (DrVSP) to
study TRPC3/C6/C7 regulation and found that the channel activity was controlled by
PtdIns(4,5)P2-DAG signaling in a self-limiting manner (Imai Y et al., the
Journal of Physiology, 2012). In this addendum, we present the advantages of using DrVSP
as a molecular tool to study PtdIns(4,5)P2 regulation. DrVSP should be readily
applicable for studying phosphoinositide metabolism-linked channel regulation as well as
lipid dynamics. Furthermore, in comparison to other modes of self-limiting ion channel
regulation, the regulation of TRPC3/C6/C7 channels seems highly susceptible to activation
signal strength, which could potentially affect both open duration and the time to peak
activation and inactivation. Dysfunction of such self-limiting regulation may contribute
to the pathology of the cardiovascular system, gastrointestinal tract and brain, as these
channels are broadly distributed and affected by numerous neurohormonal agonists.
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Affiliation(s)
- Kyohei Itsuki
- Department of Physiology, School of Medicine, Fukuoka University, Japan
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