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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: 125] [Impact Index Per Article: 31.3] [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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Vinayagam D, Mager T, Apelbaum A, Bothe A, Merino F, Hofnagel O, Gatsogiannis C, Raunser S. Electron cryo-microscopy structure of the canonical TRPC4 ion channel. eLife 2018; 7:e36615. [PMID: 29717981 PMCID: PMC5951680 DOI: 10.7554/elife.36615] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 04/30/2018] [Indexed: 12/31/2022] Open
Abstract
Canonical transient receptor channels (TRPC) are non-selective cation channels. They are involved in receptor-operated Ca2+ signaling and have been proposed to act as store-operated channels (SOC). Their malfunction is related to cardiomyopathies and their modulation by small molecules has been shown to be effective against renal cancer cells. The molecular mechanism underlying the complex activation and regulation is poorly understood. Here, we report the electron cryo-microscopy structure of zebrafish TRPC4 in its unliganded (apo), closed state at an overall resolution of 3.6 Å. The structure reveals the molecular architecture of the cation conducting pore, including the selectivity filter and lower gate. The cytoplasmic domain contains two key hubs that have been shown to interact with modulating proteins. Structural comparisons with other TRP channels give novel insights into the general architecture and domain organization of this superfamily of channels and help to understand their function and pharmacology.
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Affiliation(s)
| | - Thomas Mager
- Department of Biophysical ChemistryMax Planck Institute of BiophysicsFrankfurt am MainGermany
| | - Amir Apelbaum
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Arne Bothe
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Felipe Merino
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Oliver Hofnagel
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Christos Gatsogiannis
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
| | - Stefan Raunser
- Department of Structural BiochemistryMax Planck Institute of Molecular PhysiologyDortmundGermany
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3
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Groschner K, Shrestha N, Fameli N. Cardiovascular and Hemostatic Disorders: SOCE in Cardiovascular Cells: Emerging Targets for Therapeutic Intervention. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:473-503. [PMID: 28900929 DOI: 10.1007/978-3-319-57732-6_24] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The discovery of the store-operated Ca2+ entry (SOCE) phenomenon is tightly associated with its recognition as a pathway of high (patho)physiological significance in the cardiovascular system. Early on, SOCE has been investigated primarily in non-excitable cell types, and the vascular endothelium received particular attention, while a role of SOCE in excitable cells, specifically cardiac myocytes and pacemakers, was initially ignored and remains largely enigmatic even to date. With the recent gain in knowledge on the molecular components of SOCE as well as their cellular organization within nanodomains, potential tissue/cell type-dependent heterogeneity of the SOCE machinery along with high specificity of linkage to downstream signaling pathways emerged for cardiovascular cells. The basis of precise decoding of cellular Ca2+ signals was recently uncovered to involve correct spatiotemporal organization of signaling components, and even minor disturbances in these assemblies trigger cardiovascular pathologies. With this chapter, we wish to provide an overview on current concepts of cellular organization of SOCE signaling complexes in cardiovascular cells with particular focus on the spatiotemporal aspects of coupling to downstream signaling and the potential disturbance of these mechanisms by pathogenic factors. The significance of these mechanistic concepts for the development of novel therapeutic strategies will be discussed.
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Affiliation(s)
- Klaus Groschner
- Institute of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/4, 8010, Graz, Austria.
| | - Niroj Shrestha
- Institute of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/4, 8010, Graz, Austria
| | - Nicola Fameli
- Institute of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/4, 8010, Graz, Austria
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC, Canada
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Ohya S, Kito H, Hatano N, Muraki K. Recent advances in therapeutic strategies that focus on the regulation of ion channel expression. Pharmacol Ther 2016; 160:11-43. [PMID: 26896566 DOI: 10.1016/j.pharmthera.2016.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of different ion channel types are involved in cell signaling networks, and homeostatic regulatory mechanisms contribute to the control of ion channel expression. Profiling of global gene expression using microarray technology has recently provided novel insights into the molecular mechanisms underlying the homeostatic and pathological control of ion channel expression. It has demonstrated that the dysregulation of ion channel expression is associated with the pathogenesis of neural, cardiovascular, and immune diseases as well as cancers. In addition to the transcriptional, translational, and post-translational regulation of ion channels, potentially important evidence on the mechanisms controlling ion channel expression has recently been accumulated. The regulation of alternative pre-mRNA splicing is therefore a novel therapeutic strategy for the treatment of dominant-negative splicing disorders. Epigenetic modification plays a key role in various pathological conditions through the regulation of pluripotency genes. Inhibitors of pre-mRNA splicing and histone deacetyalase/methyltransferase have potential as potent therapeutic drugs for cancers and autoimmune and inflammatory diseases. Moreover, membrane-anchoring proteins, lysosomal and proteasomal degradation-related molecules, auxiliary subunits, and pharmacological agents alter the protein folding, membrane trafficking, and post-translational modifications of ion channels, and are linked to expression-defect channelopathies. In this review, we focused on recent insights into the transcriptional, spliceosomal, epigenetic, and proteasomal regulation of ion channel expression: Ca(2+) channels (TRPC/TRPV/TRPM/TRPA/Orai), K(+) channels (voltage-gated, KV/Ca(2+)-activated, KCa/two-pore domain, K2P/inward-rectifier, Kir), and Ca(2+)-activated Cl(-) channels (TMEM16A/TMEM16B). Furthermore, this review highlights expression of these ion channels in expression-defect channelopathies.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan.
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Kim J, Moon SH, Shin YC, Jeon JH, Park KJ, Lee KP, So I. Intracellular spermine blocks TRPC4 channel via electrostatic interaction with C-terminal negative amino acids. Pflugers Arch 2015; 468:551-61. [PMID: 26631167 DOI: 10.1007/s00424-015-1753-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/27/2015] [Accepted: 10/29/2015] [Indexed: 01/09/2023]
Abstract
Transient receptor potential canonical (TRPC) 4 channels are calcium-permeable, nonselective cation channels and are widely expressed in mammalian tissue, especially in the GI tract and brain. TRPC4 channels are known to be involved in neurogenic contraction of ileal smooth muscle cells via generating cationic current after muscarinic stimulation (muscarinic cationic current (mIcat)). Polyamines exist in numerous tissues and are believed to be involved in cell proliferation, differentiation, scar formation, wound healing, and carcinogenesis. Besides, physiological polyamines are essential to maintain inward rectification of cardiac potassium channels (Kir2.1). At membrane potentials more positive than equilibrium potential, intracellular polyamines plug the cytosolic surface of the Kir2.1 so that potassium ions cannot pass through the pore. Recently, it was reported that polyamines inhibit not only cardiac potassium channels but also nonselective cation channels that mediate the generation of mIcat. Here, we report that TRPC4, a definite mIcat mediator, is inhibited by intracellular spermine with great extent. The inhibition was specific to TRPC4 and TRPC5 channels but was not effective to TRPC1/4, TRPC1/5, and TRPC3 channels. For this inhibition to occur, we found that glutamates at 728th and 729th position of TRPC4 channels are essential whereby we conclude that spermine blocks the TRPC4 channel with electrostatic interaction between negative amino acids at the C-terminus of the channel.
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Affiliation(s)
- Jinsung Kim
- College of Medicine, Catholic University of Korea, Seoul, 137-701, Republic of Korea.,Department of Physiology, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea
| | - Sang Hui Moon
- Department of Surgery, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea
| | - Young-Cheul Shin
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea
| | - Ju-Hong Jeon
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea
| | - Kyu Joo Park
- Department of Surgery, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea
| | - Kyu Pil Lee
- Department of Physiology, College of Veterinary Medicine, Chungnam National University, Daejeon, 305-764, Republic of Korea.
| | - Insuk So
- Department of Physiology, College of Medicine, Seoul National University, Seoul, 110-799, Republic of Korea.
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Redondo PC, Rosado JA. Store-operated calcium entry: unveiling the calcium handling signalplex. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 316:183-226. [PMID: 25805125 DOI: 10.1016/bs.ircmb.2015.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) is an important mechanism for Ca(2+) influx in non-excitable cells, also present in excitable cells. The activation of store-operated channels (SOCs) is finely regulated by the filling state of the intracellular agonist-sensitive Ca(2+) compartments, and both, the mechanism of sensing the Ca(2+) stores and the nature and functional properties of the SOCs, have been a matter of intense investigation and debate. The identification of STIM1 as the endoplasmic reticulum Ca(2+) sensor and both Orai1, as the pore-forming subunit of the channels mediating the Ca(2+)-selective store-operated current, and the members of the TRPC subfamily of proteins, as the channels mediating the cation-permeable SOCs, has shed new light on the underlying events. This review summarizes the initial hypothesis and the current advances on the mechanism of activation of SOCE.
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Affiliation(s)
- Pedro C Redondo
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Cáceres, Spain
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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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8
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Myeong J, Kwak M, Hong C, Jeon JH, So I. Identification of a membrane-targeting domain of the transient receptor potential canonical (TRPC)4 channel unrelated to its formation of a tetrameric structure. J Biol Chem 2014; 289:34990-5002. [PMID: 25349210 DOI: 10.1074/jbc.m114.584649] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Canonical transient receptor potential (TRPC) channels are Ca(2+)-permeable nonselective cation channels that are activated by a wide variety of stimuli, including G protein-coupled receptors (GPCRs). The TRPC4 channel is expressed in a punctate distribution in the membrane. To identify the regulating region of the channel trafficking to the membrane, we generated deletion mutants of the TRPC4 channel. We determined that when either region that was downstream of the 20 amino acids of the N terminus or the 700-730 amino acids was deleted, the mutants were retained in the endoplasmic reticulum. By coexpression of the wild-type TRPC4 with deletion mutants, we found that the 23-29 amino acids of the N terminus regulate a membrane trafficking. Additionally, by the fluorescence resonance energy transfer (FRET) method, we found that the regions downstream of the 99 amino acid region of the N terminus and upstream of the 730 amino acid region in the C terminus produce assembly of the TRPC4 tetramers. We inferred the candidate proteins that regulate or interact with the 23-29 domain of TRPC4.
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Affiliation(s)
- Jongyun Myeong
- From the Department of Physiology, Seoul National University College of Medicine
| | - Misun Kwak
- From the Department of Physiology, Seoul National University College of Medicine
| | - Chansik Hong
- From the Department of Physiology, Seoul National University College of Medicine
| | - Ju-Hong Jeon
- From the Department of Physiology, Seoul National University College of Medicine
| | - Insuk So
- From the Department of Physiology, Seoul National University College of Medicine
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9
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Ding XQ, Matveev A, Singh A, Komori N, Matsumoto H. Exploration of cone cyclic nucleotide-gated channel-interacting proteins using affinity purification and mass spectrometry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:57-65. [PMID: 24664681 DOI: 10.1007/978-1-4614-3209-8_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Photopic (cone) vision essential for color sensation, central vision, and visual acuity is mediated by the activation of photoreceptor cyclic nucleotide-gated (CNG) channels. Naturally occurring mutations in the cone channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. This work investigated the functional modulation of cone CNG channel by exploring the channel-interacting proteins. Retinal protein extracts prepared from cone-dominant Nrl (- / -) mice were used in CNGA3 antibody affinity purification, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) separation and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis. The peptide mass fingerprinting of the tryptic digests and database search identified a number of proteins including spectrin alpha-2, ATPase (Na(+)/K(+) transporting) alpha-3, alpha and beta subunits of ATP synthase (H(+) transporting, mitochondrial F1 complex), and alpha-2 subunit of the guanine nucleotide-binding protein. In addition, the affinity-binding assays demonstrated an interaction between cone CNG channel and calmodulin but not cone Na(+)/Ca(2+)-K(+) exchanger in the mouse retina. Results of this study provide insight into our understanding of cone CNG channel-interacting proteins and the functional modulations.
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Affiliation(s)
- Xi-Qin Ding
- Departments of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 553, 73104, Oklahoma City, OK, USA,
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Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Zimmermann J, Latta L, Beck A, Leidinger P, Fecher-Trost C, Schlenstedt G, Meese E, Wissenbach U, Flockerzi V. Trans-activation response (TAR) RNA-binding protein 2 is a novel modulator of transient receptor potential canonical 4 (TRPC4) protein. J Biol Chem 2014; 289:9766-80. [PMID: 24563462 DOI: 10.1074/jbc.m114.557066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
TRPC4 proteins function as Ca(2+) conducting, non-selective cation channels in endothelial, smooth muscle, and neuronal cells. To further characterize the roles of TRPC4 in vivo, detailed information about the molecular composition of native channel complexes and their association with cellular signaling networks is needed. Therefore, a mouse brain cDNA library was searched for novel TRPC4-interacting proteins using a modified yeast two-hybrid assay. This screen identified Trans-activation Response RNA-binding protein 2 (Tarpb2), a protein that recruits the Dicer complex to Ago2 for microRNA processing and gene silencing. Tarbp2 was found to bind to the C terminus of TRPC4 and TRPC5 and to modulate agonist-dependent TRPC4-induced Ca(2+) entry. A stretch of basic residues within the Tarbp2 protein is required for these actions. Tarbp2 binding to and modulation of TRPC4 occurs in the presence of endogenously expressed Dicer but is no longer detectable when the Dicer cDNA is overexpressed. Dicer activity in crude cell lysates is increased in the presence of Ca(2+), most probably by Ca(2+)-dependent proteolytic activation of Dicer. Apparently, Tarbp2 binding to TRPC4 promotes changes of cytosolic Ca(2+) and, thereby, leads to a dynamic regulation of Dicer activity, essentially at low endogenous Dicer concentrations.
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Affiliation(s)
- Jasmin Zimmermann
- From the Institut für Experimentelle und Klinische Pharmakologie und Toxikologie
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12
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Abstract
TRPC4 proteins comprise six transmembrane domains, a putative pore-forming region, and an intracellularly located amino- and carboxy-terminus. Among eleven splice variants identified so far, TRPC4α and TRPC4β are the most abundantly expressed and functionally characterized. TRPC4 is expressed in various organs and cell types including the soma and dendrites of numerous types of neurons; the cardiovascular system including endothelial, smooth muscle, and cardiac cells; myometrial and skeletal muscle cells; kidney; and immune cells such as mast cells. Both recombinant and native TRPC4-containing channels differ tremendously in their permeability and other biophysical properties, pharmacological modulation, and mode of activation depending on the cellular environment. They vary from inwardly rectifying store-operated channels with a high Ca(2+) selectivity to non-store-operated channels predominantly carrying Na(+) and activated by Gαq- and/or Gαi-coupled receptors with a complex U-shaped current-voltage relationship. Thus, individual TRPC4-containing channels contribute to agonist-induced Ca(2+) entry directly or indirectly via depolarization and activation of voltage-gated Ca(2+) channels. The differences in channel properties may arise from variations in the composition of the channel complexes, in the specific regulatory pathways in the corresponding cell system, and/or in the expression pattern of interaction partners which comprise other TRPC proteins to form heteromultimeric channels. Additional interaction partners of TRPC4 that can mediate the activity of TRPC4-containing channels include (1) scaffolding proteins (e.g., NHERF) that may mediate interactions with signaling molecules in or in close vicinity to the plasma membrane such as Gα proteins or phospholipase C and with the cytoskeleton, (2) proteins in specific membrane microdomains (e.g., caveolin-1), or (3) proteins on cellular organelles (e.g., Stim1). The diversity of TRPC4-containing channels hampers the development of specific agonists or antagonists, but recently, ML204 was identified as a blocker of both recombinant and endogenous TRPC4-containing channels with an IC50 in the lower micromolar range that lacks activity on most voltage-gated channels and other TRPs except TRPC5 and TRPC3. Lanthanides are specific activators of heterologously expressed TRPC4- and TRPC5-containing channels but can block individual native TRPC4-containing channels. The biological relevance of TRPC4-containing channels was demonstrated by knockdown of TRPC4 expression in numerous native systems including gene expression, cell differentiation and proliferation, formation of myotubes, and axonal regeneration. Studies of TRPC4 single and TRPC compound knockout mice uncovered their role for the regulation of vascular tone, endothelial permeability, gastrointestinal contractility and motility, neurotransmitter release, and social exploratory behavior as well as for excitotoxicity and epileptogenesis. Recently, a single-nucleotide polymorphism (SNP) in the Trpc4 gene was associated with a reduced risk for experience of myocardial infarction.
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Affiliation(s)
- Marc Freichel
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany,
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Ning L, Wang C, Fan X, Ding X, Wang Y, Zhang Y, Wang J, Yue S. Role of colchicine-induced microtubule depolymerization in hyperalgesia via TRPV4 in rats with chronic compression of the dorsal root ganglion. Neurol Res 2013; 36:70-8. [PMID: 24074178 DOI: 10.1179/1743132813y.0000000261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this study is to investigate the effect of microtubule depolymerization by colchicine on hyperalgesia mediated by transient receptor potential vanilloid 4 (TRPV4) in a neuropathic pain model of chronic compression of the dorsal root ganglion (DRG) (hereafter termed CCD) in rat. Intrathecal administration of microtubule-depolymerizing agent, colchicine, attenuated the activated effect of 4alpha-phorbol 12, 13-didecanoate (4alpha-PDD, TRPV4 specific agonist) on mechanical and thermal hyperalgesia in CCD rats. This observation is in agreement with our in vitro experiments with DRG cells that showed a significant attenuation of 4alpha-PDD-activated Ca(2+)-influx and substance P (SP) release with the colchicine treatment. We conclude that microtubule depolymerization by colchicine can regulate pain sensitivity by depressing the hyperalgesia mediated by TRPV4.
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Chitta KR, Landero Figueroa JA, Caruso JA, Merino EJ. Selenium mediated arsenic toxicity modifies cytotoxicity, reactive oxygen species and phosphorylated proteins. Metallomics 2013; 5:673-85. [DOI: 10.1039/c3mt20213e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Kim H, Kim J, Jeon JP, Myeong J, Wie J, Hong C, Kim HJ, Jeon JH, So I. The roles of G proteins in the activation of TRPC4 and TRPC5 transient receptor potential channels. Channels (Austin) 2012; 6:333-43. [PMID: 22878724 PMCID: PMC3508772 DOI: 10.4161/chan.21198] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
TRPC4 and TRPC5 channels are important regulators of electrical excitability in both gastrointestinal myocytes and neurons. Much is known regarding the assembly and function of these channels including TRPC1 as a homotetramer or a heteromultimer and the roles that their interacting proteins play in controlling these events. Further, they are one of the best-studied targets of G protein-coupled receptors and growth factors in general and Gαq protein coupled receptor or epidermal growth factor in particular. However, our understanding of the roles of Gαi/o proteins on TRPC4/5 channels is still rudimentary. We discuss potential roles for Gαi/o proteins in channel activation in addition to their known role in cellular signaling.
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Affiliation(s)
- Hana Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
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16
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Li F, Wang W, Gu M, Gyoneva S, Zhang J, Huang S, Traynelis SF, Cai H, Guggino SE, Zhang X. L-type calcium channel activity in osteoblast cells is regulated by the actin cytoskeleton independent of protein trafficking. J Bone Miner Metab 2011; 29:515-25. [PMID: 21246227 DOI: 10.1007/s00774-010-0252-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 11/14/2010] [Indexed: 11/27/2022]
Abstract
Voltage-dependent L-type calcium channels (VDCC) play important roles in many cellular processes. The interaction of the actin cytoskeleton with the channel in nonexcitable cells is less well understood. We performed whole-cell patch-clamp surface biotinylation and calcium imaging on different osteoblast cells to determine channel kinetics, amplitude, surface abundance, and intracellular calcium, respectively. Patch-clamp studies showed that actin polymerization by phalloidin increased the peak current density of I (Ca), whereas actin depolymerization by cytochalasin D (CD) significantly decreased the current amplitude. This result is consistent with calcium imaging, which showed that CD significantly decreased Bay K8644-induced intracellular calcium increase. Surface biotinylation studies showed that CD is not able to affect the surface expression of the pore-forming subunit α(1C). Interestingly, application of CD caused a significantly negative shift in the steady-state inactivation kinetics of I (Ca). There were decreases in the voltage at half-maximal inactivation that changed in a dose-dependent manner. CD also reduced the effect of activated vitamin D(3) (1α,25-D3) on VDCC and intracellular calcium. We conclude that in osteoblasts the actin cytoskeleton affects α(1C) by altering the channel kinetic properties, instead of changing the surface expression, and it is able to regulate 1α,25-D3 signaling through VDCC. Our study provides a new insight into calcium regulation in osteoblasts, which are essential in many physiological functions of this cell.
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Affiliation(s)
- Fangping Li
- Department of Pharmacology, School of Pharmacy, Fudan University, Pudong New District, Shanghai, China
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17
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Machnicka B, Grochowalska R, Bogusławska DM, Sikorski AF, Lecomte MC. Spectrin-based skeleton as an actor in cell signaling. Cell Mol Life Sci 2011; 69:191-201. [PMID: 21877118 PMCID: PMC3249148 DOI: 10.1007/s00018-011-0804-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/08/2011] [Accepted: 08/10/2011] [Indexed: 01/12/2023]
Abstract
This review focuses on the recent advances in functions of spectrins in non-erythroid cells. We discuss new data concerning the commonly known role of the spectrin-based skeleton in control of membrane organization, stability and shape, and tethering protein mosaics to the cellular motors and to all major filament systems. Particular effort has been undertaken to highlight recent advances linking spectrin to cell signaling phenomena and its participation in signal transduction pathways in many cell types.
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Affiliation(s)
- B Machnicka
- University of Zielona Góra, Zielona Góra, Poland
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18
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Hirschler-Laszkiewicz I, Tong Q, Waybill K, Conrad K, Keefer K, Zhang W, Chen SJ, Cheung JY, Miller BA. The transient receptor potential (TRP) channel TRPC3 TRP domain and AMP-activated protein kinase binding site are required for TRPC3 activation by erythropoietin. J Biol Chem 2011; 286:30636-30646. [PMID: 21757714 DOI: 10.1074/jbc.m111.238360] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Modulation of intracellular calcium ([Ca(2+)](i)) by erythropoietin (Epo) is an important signaling pathway controlling erythroid proliferation and differentiation. Transient receptor potential (TRP) channels TRPC3 and homologous TRPC6 are expressed on normal human erythroid precursors, but Epo stimulates an increase in [Ca(2+)](i) through TRPC3 but not TRPC6. Here, the role of specific domains in the different responsiveness of TRPC3 and TRPC6 to erythropoietin was explored. TRPC3 and TRPC6 TRP domains differ in seven amino acids. Substitution of five amino acids (DDKPS) in the TRPC3 TRP domain with those of TRPC6 (EERVN) abolished the Epo-stimulated increase in [Ca(2+)](i). Substitution of EERVN in TRPC6 TRP domain with DDKPS in TRPC3 did not confer Epo responsiveness. However, substitution of TRPC6 TRP with DDKPS from TRPC3 TRP, as well as swapping the TRPC6 distal C terminus (C2) with that of TRPC3, resulted in a chimeric TRPC6 channel with Epo responsiveness similar to TRPC3. Substitution of TRPC6 with TRPC3 TRP and the putative TRPC3 C-terminal AMP-activated protein kinase (AMPK) binding site straddling TRPC3 C1/C2 also resulted in TRPC6 activation. In contrast, substitution of the TRPC3 C-terminal leucine zipper motif or TRPC3 phosphorylation sites Ser-681, Ser-708, or Ser-764 with TRPC6 sequence did not affect TRPC3 Epo responsiveness. TRPC3, but not TRPC6, and TRPC6 chimeras expressing TRPC3 C2 showed significantly increased plasma membrane insertion following Epo stimulation and substantial cytoskeletal association. The TRPC3 TRP domain, distal C terminus (C2), and AMPK binding site are critical elements that confer Epo responsiveness. In particular, the TRPC3 C2 and AMPK site are essential for association of TRPC3 with the cytoskeleton and increased channel translocation to the cell surface in response to Epo stimulation.
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Affiliation(s)
| | - Qin Tong
- Departments of Pediatrics, Hershey, Pennsylvania 17033
| | | | | | - Kerry Keefer
- Departments of Pediatrics, Hershey, Pennsylvania 17033
| | - Wenyi Zhang
- Departments of Pediatrics, Hershey, Pennsylvania 17033
| | - Shu-Jen Chen
- Departments of Pediatrics, Hershey, Pennsylvania 17033
| | - Joseph Y Cheung
- Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania 19107
| | - Barbara A Miller
- Departments of Pediatrics, Hershey, Pennsylvania 17033; Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033.
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19
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Linde CI, Baryshnikov SG, Mazzocco-Spezzia A, Golovina VA. Dysregulation of Ca2+ signaling in astrocytes from mice lacking amyloid precursor protein. Am J Physiol Cell Physiol 2011; 300:C1502-12. [PMID: 21368296 DOI: 10.1152/ajpcell.00379.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The relationship between altered metabolism of the amyloid-β precursor protein (APP) and Alzheimer's disease is well established but the physiological roles of APP still remain unclear. Here, we studied Ca(2+) signaling in primary cultured and freshly dissociated cortical astrocytes from APP knockout (KO) mice and from Tg5469 mice overproducing by five- to sixfold wild-type APP. Resting cytosolic Ca(2+) (measured with fura-2) was not altered in cultured astrocytes from APP KO mice. The stored Ca(2+) evaluated by measuring peak amplitude of cyclopiazonic acid [CPA, endoplasmic reticulum (ER) Ca(2+) ATPase inhibitor]-induced Ca(2+) transients in Ca(2+)-free medium was significantly smaller in APP KO astrocytes than in wild-type cells. Store-operated Ca(2+) entry (SOCE) activated by ER Ca(2+) store depletion with CPA was also greatly reduced in APP KO astrocytes. This reflected a downregulated expression in APP KO astrocytes of TRPC1 (C-type transient receptor potential) and Orai1 proteins, essential components of store-operated channels (SOCs). Indeed, silencer RNA (siRNA) knockdown of Orai1 protein expression in wild-type astrocytes significantly attenuated SOCE. SOCE was also essentially reduced in freshly dissociated APP KO astrocytes. Importantly, knockdown of APP with siRNA in cultured wild-type astrocytes markedly attenuated ATP- and CPA-induced ER Ca(2+) release and extracellular Ca(2+) influx. The latter correlated with downregulation of TRPC1. Overproduction of APP in Tg5469 mice did not alter, however, the stored Ca(2+) level, SOCE, and expression of TRPC1/4/5 in cultured astrocytes from these mice. The data demonstrate that the functional role of APP in astrocytes involves the regulation of TRPC1/Orai1-encoded SOCs critical for Ca(2+) signaling.
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Affiliation(s)
- Cristina I Linde
- Dept. of Physiology, University of Maryland School of Medicine, 685 W. Baltimore Street, Baltimore, MD 21201, USA
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20
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TRP channels in the cardiopulmonary vasculature. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:781-810. [PMID: 21290327 DOI: 10.1007/978-94-007-0265-3_41] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transient receptor potential (TRP) channels are expressed in almost every human tissue, including the heart and the vasculature. They play unique roles not only in physiological functions but, if over-expressed, also in pathophysiological disease states. Cardiovascular diseases are the leading cause of death in the industrialized countries. Therefore, TRP channels are attractive drug targets for more effective pharmacological treatments of these diseases. This review focuses on three major cell types of the cardiovascular system: cardiomyocytes as well as smooth muscle cells and endothelial cells from the systemic and pulmonary circulation. TRP channels initiate multiple signals in all three cell types (e.g. contraction, migration) and are involved in gene transcription leading to cell proliferation or cell death. Identification of their genes has significantly improved our knowledge of multiple signal transduction pathways in these cells. Some TRP channels are important cellular sensors and are mostly permeable to Ca(2+), while most other TRP channels are receptor activated and allow for the entry of Na(+), Ca(2+) and Mg(2+). Physiological functions of TRPA, TRPC, TRPM, TRPP and TRPV channels in the cardiovascular system, dissected by down-regulating channel activity in isolated tissues or by the analysis of gene-deficient mouse models, are reviewed. The involvement of TRPs as homomeric or heteromeric channels in pathophysiological processes in the cardiovascular system like heart failure, cardiac hypertrophy, hypertension as well as edema formation by increased endothelial permeability will be discussed.
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21
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Regulation of TRP signalling by ion channel translocation between cell compartments. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:545-72. [PMID: 21290316 DOI: 10.1007/978-94-007-0265-3_30] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The TRP (transient receptor potential) family of ion channels is a heterogeneous family of calcium permeable cation channels that is subdivided into seven subfamilies: TRPC ("Canonical"), TRPV ("Vanilloid"), TRPM ("Melastatin"), TRPA ("Ankyrin"), TRPN ("NOMPC"), TRPP ("Polycystin"), and TRPML ("Mucolipin"). TRP-mediated ion currents across the cell membrane are determined by the single channel conductance, by the fraction of activated channels, and by the total amount of TRP channels present at the plasma membrane. In many cases, the amount of TRP channels at the plasma membrane is altered in response to physiological stimuli by translocation of channels to and from the plasma membrane. Regulated translocation has been described for channels of the TRPC, TRPV, TRPM, and TRPA family and is achieved by vesicular transport of these channels along cellular exocytosis and endocytosis pathways. This review summarizes the stimuli and signalling cascades involved in the translocation of TRP channels and highlights interactions of TRP channels with proteins of the endocytosis and exocytosis machineries.
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22
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Ray M, Zhang W. Analysis of Alzheimer's disease severity across brain regions by topological analysis of gene co-expression networks. BMC SYSTEMS BIOLOGY 2010; 4:136. [PMID: 20925940 PMCID: PMC2976747 DOI: 10.1186/1752-0509-4-136] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 10/06/2010] [Indexed: 11/01/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive neurodegenerative disorder involving variations in the transcriptome of many genes. AD does not affect all brain regions simultaneously. Identifying the differences among the affected regions may shed more light onto the disease progression. We developed a novel method involving the differential topology of gene coexpression networks to understand the association among affected regions and disease severity. METHODS We analysed microarray data of four regions--entorhinal cortex (EC), hippocampus (HIP), posterior cingulate cortex (PCC) and middle temporal gyrus (MTG) from AD affected and normal subjects. A coexpression network was built for each region and the topological overlap between them was examined. Genes with zero topological overlap between two region-specific networks were used to characterise the differences between the two regions. RESULTS AND CONCLUSION Results indicate that MTG shows early AD pathology compared to the other regions. We postulate that if the MTG gets affected later in the disease, post-mortem analyses of individuals with end-stage AD will show signs of early AD in the MTG, while the EC, HIP and PCC will have severe pathology. Such knowledge is useful for data collection in clinical studies where sample selection is a limiting factor as well as highlighting the underlying biology of disease progression.
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Affiliation(s)
- Monika Ray
- Washington University School of Engineering, Dept of Computer Science and Engineering, Saint Louis, MO 63130, USA
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23
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Baines AJ. The spectrin-ankyrin-4.1-adducin membrane skeleton: adapting eukaryotic cells to the demands of animal life. PROTOPLASMA 2010; 244:99-131. [PMID: 20668894 DOI: 10.1007/s00709-010-0181-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 07/05/2010] [Indexed: 05/29/2023]
Abstract
The cells in animals face unique demands beyond those encountered by their unicellular eukaryotic ancestors. For example, the forces engendered by the movement of animals places stresses on membranes of a different nature than those confronting free-living cells. The integration of cells into tissues, as well as the integration of tissue function into whole animal physiology, requires specialisation of membrane domains and the formation of signalling complexes. With the evolution of mammals, the specialisation of cell types has been taken to an extreme with the advent of the non-nucleated mammalian red blood cell. These and other adaptations to animal life seem to require four proteins--spectrin, ankyrin, 4.1 and adducin--which emerged during eumetazoan evolution. Spectrin, an actin cross-linking protein, was probably the earliest of these, with ankyrin, adducin and 4.1 only appearing as tissues evolved. The interaction of spectrin with ankyrin is probably a prerequisite for the formation of tissues; only with the advent of vertebrates did 4.1 acquires the ability to bind spectrin and actin. The latter activity seems to allow the spectrin complex to regulate the cell surface accumulation of a wide variety of proteins. Functionally, the spectrin-ankyrin-4.1-adducin complex is implicated in the formation of apical and basolateral domains, in aspects of membrane trafficking, in assembly of certain signalling and cell adhesion complexes and in providing stability to otherwise mechanically fragile cell membranes. Defects in this complex are manifest in a variety of hereditary diseases, including deafness, cardiac arrhythmia, spinocerebellar ataxia, as well as hereditary haemolytic anaemias. Some of these proteins also function as tumor suppressors. The spectrin-ankyrin-4.1-adducin complex represents a remarkable system that underpins animal life; it has been adapted to many different functions at different times during animal evolution.
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Affiliation(s)
- Anthony J Baines
- School of Biosciences and Centre for Biomedical Informatics, University of Kent, Canterbury, CT2 7NJ, UK.
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Importance of non-selective cation channel TRPV4 interaction with cytoskeleton and their reciprocal regulations in cultured cells. PLoS One 2010; 5:e11654. [PMID: 20657843 PMCID: PMC2906515 DOI: 10.1371/journal.pone.0011654] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 06/15/2010] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND TRPV4 and the cellular cytoskeleton have each been reported to influence cellular mechanosensitive processes as well as the development of mechanical hyperalgesia. If and how TRPV4 interacts with the microtubule and actin cytoskeleton at a molecular and functional level is not known. METHODOLOGY AND PRINCIPAL FINDINGS We investigated the interaction of TRPV4 with cytoskeletal components biochemically, cell biologically by observing morphological changes of DRG-neurons and DRG-neuron-derived F-11 cells, as well as functionally with calcium imaging. We find that TRPV4 physically interacts with tubulin, actin and neurofilament proteins as well as the nociceptive molecules PKCepsilon and CamKII. The C-terminus of TRPV4 is sufficient for the direct interaction with tubulin and actin, both with their soluble and their polymeric forms. Actin and tubulin compete for binding. The interaction with TRPV4 stabilizes microtubules even under depolymerizing conditions in vitro. Accordingly, in cellular systems TRPV4 colocalizes with actin and microtubules enriched structures at submembranous regions. Both expression and activation of TRPV4 induces striking morphological changes affecting lamellipodial, filopodial, growth cone, and neurite structures in non-neuronal cells, in DRG-neuron derived F11 cells, and also in IB4-positive DRG neurons. The functional interaction of TRPV4 and the cytoskeleton is mutual as Taxol, a microtubule stabilizer, reduces the Ca2+-influx via TRPV4. CONCLUSIONS AND SIGNIFICANCE TRPV4 acts as a regulator for both, the microtubule and the actin. In turn, we describe that microtubule dynamics are an important regulator of TRPV4 activity. TRPV4 forms a supra-molecular complex containing cytoskeletal proteins and regulatory kinases. Thereby it can integrate signaling of various intracellular second messengers and signaling cascades, as well as cytoskeletal dynamics. This study points out the existence of cross-talks between non-selective cation channels and cytoskeleton at multiple levels. These cross talks may help us to understand the molecular basis of the Taxol-induced neuropathic pain development commonly observed in cancer patients.
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25
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Zulian A, Baryshnikov SG, Linde CI, Hamlyn JM, Ferrari P, Golovina VA. Upregulation of Na+/Ca2+ exchanger and TRPC6 contributes to abnormal Ca2+ homeostasis in arterial smooth muscle cells from Milan hypertensive rats. Am J Physiol Heart Circ Physiol 2010; 299:H624-33. [PMID: 20622104 DOI: 10.1152/ajpheart.00356.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Milan hypertensive strain (MHS) of rats is a model for hypertension in humans. Inherited defects in renal function have been well studied in MHS rats, but the mechanisms that underlie the elevated vascular resistance are unclear. Altered Ca(2+) signaling plays a key role in the vascular dysfunction associated with arterial hypertension. Here we compared Ca(2+) signaling in mesenteric artery smooth muscle cells from MHS rats and its normotensive counterpart (MNS). Systolic blood pressure was higher in MHS than in MNS rats (144 +/- 2 vs. 113 +/- 1 mmHg, P < 0.05). Resting cytosolic free Ca(2+) concentration (measured with fura-2) and ATP-induced Ca(2+) transients were augmented in freshly dissociated arterial myocytes from MHS rats. Ba(2+) entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl-sn-glycerol (a measure of receptor-operated channel activity) was much greater in MHS than MNS arterial myocytes. This correlated with a threefold upregulation of transient receptor potential canonical 6 (TRPC6) protein. TRPC3, the other component of receptor-operated channels, was marginally, but not significantly, upregulated. The expression of TRPC1/5, components of store-operated channels, was not altered in MHS mesenteric artery smooth muscle. Immunoblots also revealed that the Na(+)/Ca(2+) exchanger-1 (NCX1) was greatly upregulated in MHS mesenteric artery (by approximately 13-fold), whereas the expression of plasma membrane Ca(2+)-ATPase was not altered. Ca(2+) entry via the reverse mode of NCX1 evoked by the removal of extracellular Na(+) induced a rapid increase in cytosolic free Ca(2+) concentration that was significantly larger in MHS arterial myocytes. The expression of alpha(1)/alpha(2) Na(+) pumps in MHS mesenteric arteries was not changed. Immunocytochemical observations showed that NCX1 and TRPC6 are clustered in plasma membrane microdomains adjacent to the underlying sarcoplasmic reticulum. In summary, MHS arteries exhibit upregulated TRPC6 and NCX1 and augmented Ca(2+) signaling. We suggest that the increased Ca(2+) signaling contributes to the enhanced vasoconstriction and elevated blood pressure in MHS rats.
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Affiliation(s)
- Alessandra Zulian
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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26
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Miehe S, Bieberstein A, Arnould I, Ihdene O, Rütten H, Strübing C. The phospholipid-binding protein SESTD1 is a novel regulator of the transient receptor potential channels TRPC4 and TRPC5. J Biol Chem 2010; 285:12426-34. [PMID: 20164195 DOI: 10.1074/jbc.m109.068304] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
TRPC4 and TRPC5 are two closely related members of the mammalian transient receptor potential cation channel family that have been implicated in important physiological functions, such as growth cone guidance and smooth muscle contraction. To further unravel the role of TRPC4 and TRPC5 in these processes in vivo, detailed information about the molecular composition of native channel complexes and their association with cellular signaling networks is needed. We therefore searched a human aortic cDNA library for novel TRPC4-interacting proteins using a modified yeast two-hybrid assay. This screen identified SESTD1, a previously uncharacterized protein containing a lipid-binding SEC14-like domain as well as spectrin-type cytoskeleton interaction domains. SESTD1 was found to associate with TRPC4 and TRPC5 via the channel's calmodulin- and inositol 1,4,5-trisphosphate receptor-binding domain. In functional studies, we demonstrate that SESTD1 binds several phospholipid species in vitro and is essential for efficient receptor-mediated activation of TRPC5. Notably, phospholipid binding to SESTD1 was Ca(2+)-dependent. Because TRPC4 and -5 conduct Ca(2+), SESTD1-channel signaling may be bidirectional and also couple TRPC activity to lipid signaling through SESTD1. The modulation of TRPC channel function by specific lipid-binding proteins, such as SESTD1, adds another facet to the complex regulation of these channels complementary to the previously described effects of direct channel-phospholipid interaction.
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Affiliation(s)
- Susanne Miehe
- Therapeutic Department of Cardiovascular Diseases, Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, Germany
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Graziani A, Poteser M, Heupel WM, Schleifer H, Krenn M, Drenckhahn D, Romanin C, Baumgartner W, Groschner K. Cell-cell contact formation governs Ca2+ signaling by TRPC4 in the vascular endothelium: evidence for a regulatory TRPC4-beta-catenin interaction. J Biol Chem 2009; 285:4213-4223. [PMID: 19996314 PMCID: PMC2823560 DOI: 10.1074/jbc.m109.060301] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
TRPC4 is well recognized as a prominent cation channel in the vascular endothelium, but its contribution to agonist-induced endothelial Ca2+ entry is still a matter of controversy. Here we report that the cellular targeting and Ca2+ signaling function of TRPC4 is determined by the state of cell-cell adhesions during endothelial phenotype transitions. TRPC4 surface expression in human microvascular endothelial cells (HMEC-1) increased with the formation of cell-cell contacts. Epidermal growth factor recruited TRPC4 into the plasma membrane of proliferating cells but initiated retrieval of TRPC4 from the plasma membrane in quiescent, barrier-forming cells. Epidermal growth factor-induced Ca2+ entry was strongly promoted by the formation of cell-cell contacts, and both siRNA and dominant negative knockdown experiments revealed that TRPC4 mediates stimulated Ca2+ entry exclusively in proliferating clusters that form immature cell-cell contacts. TRPC4 co-precipitated with the junctional proteins β-catenin and VE-cadherin. Analysis of cellular localization of fluorescent fusion proteins provided further evidence for recruitment of TRPC4 into junctional complexes. Analysis of TRPC4 function in the HEK293 expression system identified β-catenin as a signaling molecule that enables cell-cell contact-dependent promotion of TRPC4 function. Our results place TRPC4 as a Ca2+ entry channel that is regulated by cell-cell contact formation and interaction with β-catenin. TRPC4 is suggested to serve stimulated Ca2+ entry in a specific endothelial state during the transition from a proliferating to a quiescent phenotype. Thus, TRPC4 may adopt divergent, as yet unappreciated functions in endothelial Ca2+ homeostasis and emerges as a potential key player in endothelial phenotype switching and tuning of cellular growth factor signaling.
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Affiliation(s)
- Annarita Graziani
- From the Institute of Pharmaceutical Sciences-Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Michael Poteser
- From the Institute of Pharmaceutical Sciences-Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Wolfgang-Moritz Heupel
- the Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstrasse 6, 97070 Würzburg, Germany
| | - Hannes Schleifer
- From the Institute of Pharmaceutical Sciences-Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Martin Krenn
- From the Institute of Pharmaceutical Sciences-Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Detlev Drenckhahn
- the Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstrasse 6, 97070 Würzburg, Germany
| | - Christoph Romanin
- the Institute of Biophysics, University of Linz, A-4040 Linz, Austria, and
| | - Werner Baumgartner
- the Department of Cellular Neurobionics, Institute of Biology II, RWTH-Aachen University, Kopernikusstrasse 16, 52056 Aachen, Germany
| | - Klaus Groschner
- From the Institute of Pharmaceutical Sciences-Pharmacology and Toxicology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
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28
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Abramowitz J, Birnbaumer L. Physiology and pathophysiology of canonical transient receptor potential channels. FASEB J 2009; 23:297-328. [PMID: 18940894 PMCID: PMC2630793 DOI: 10.1096/fj.08-119495] [Citation(s) in RCA: 244] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 09/25/2008] [Indexed: 11/11/2022]
Abstract
The existence of a mammalian family of TRPC ion channels, direct homologues of TRP, the visual transduction channel of flies, was discovered during 1995-1996 as a consequence of research into the mechanism by which the stimulation of the receptor-Gq-phospholipase Cbeta signaling pathway leads to sustained increases in intracellular calcium. Mammalian TRPs, TRPCs, turned out to be nonselective, calcium-permeable cation channels, which cause both a collapse of the cell's membrane potential and entry of calcium. The family comprises 7 members and is widely expressed. Many cells and tissues express between 3 and 4 of the 7 TRPCs. Despite their recent discovery, a wealth of information has accumulated, showing that TRPCs have widespread roles in almost all cells studied, including cells from excitable and nonexcitable tissues, such as the nervous and cardiovascular systems, the kidney and the liver, and cells from endothelia, epithelia, and the bone marrow compartment. Disruption of TRPC function is at the root of some familial diseases. More often, TRPCs are contributing risk factors in complex diseases. The present article reviews what has been uncovered about physiological roles of mammalian TRPC channels since the time of their discovery. This analysis reveals TRPCs as major and unsuspected gates of Ca(2+) entry that contribute, depending on context, to activation of transcription factors, apoptosis, vascular contractility, platelet activation, and cardiac hypertrophy, as well as to normal and abnormal cell proliferation. TRPCs emerge as targets for a thus far nonexistent field of pharmacological intervention that may ameliorate complex diseases.
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Affiliation(s)
- Joel Abramowitz
- Transmembrane Signaling Group, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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