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Mehrabipour M, Jasemi NSK, Dvorsky R, Ahmadian MR. A Systematic Compilation of Human SH3 Domains: A Versatile Superfamily in Cellular Signaling. Cells 2023; 12:2054. [PMID: 37626864 PMCID: PMC10453029 DOI: 10.3390/cells12162054] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
SRC homology 3 (SH3) domains are fundamental modules that enable the assembly of protein complexes through physical interactions with a pool of proline-rich/noncanonical motifs from partner proteins. They are widely studied modular building blocks across all five kingdoms of life and viruses, mediating various biological processes. The SH3 domains are also implicated in the development of human diseases, such as cancer, leukemia, osteoporosis, Alzheimer's disease, and various infections. A database search of the human proteome reveals the existence of 298 SH3 domains in 221 SH3 domain-containing proteins (SH3DCPs), ranging from 13 to 720 kilodaltons. A phylogenetic analysis of human SH3DCPs based on their multi-domain architecture seems to be the most practical way to classify them functionally, with regard to various physiological pathways. This review further summarizes the achievements made in the classification of SH3 domain functions, their binding specificity, and their significance for various diseases when exploiting SH3 protein modular interactions as drug targets.
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Affiliation(s)
- Mehrnaz Mehrabipour
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
| | - Neda S. Kazemein Jasemi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
- Center for Interdisciplinary Biosciences, P. J. Šafárik University, 040 01 Košice, Slovakia
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (M.M.); (N.S.K.J.)
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2
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Autism associated mutations in β 2 subunit of voltage-gated calcium channels constitutively activate gene expression. Cell Calcium 2022; 108:102672. [PMID: 36427431 DOI: 10.1016/j.ceca.2022.102672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/23/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
Abstract
Membrane depolarization triggers gene expression through voltage-gated calcium channels (VGCC) in a process called Excitation-transcription (ET) coupling. Mutations in the channel subunits α11.2, or β2d, are associated with neurodevelopmental disorders such as ASD. Here, we found that two mutations S143F and G113S within the rat Cavβ2a corresponding to autistic related mutations Cavβ2dS197F and Cavβ2dG167S in the human Cavβ2d, activate ET-coupling via the RAS/ERK/CREB pathway. Membrane depolarization of HEK293 cells co-expressing α11.2 and α2δ with Cavβ2aS143F or Cavβ2aG113S triggers constitutive transcriptional activation, which is correlated with facilitated channel activity. Similar to the Timothy-associated autistic mutation α11.2G406R, constitutive gene activation is attributed to a hyperpolarizing shift in the activation kinetics of Cav1.2. Pulldown of RasGRF2 and RhoGEF by wt and the Cavβ2a autistic mutants is consistent with Cavβ2/Ras activation in ET coupling and implicates Rho signaling as yet another molecular pathway activated by Cavα11.2/Cavβ2 . Facilitated spontaneous channel activity preceding enhanced gene activation via the Ras/ERK/CREB pathway, appears a general molecular mechanism for Ca2+ channel mediated ASD and other neurodevelopmental disorders.
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Erdogmus S, Concepcion AR, Yamashita M, Sidhu I, Tao AY, Li W, Rocha PP, Huang B, Garippa R, Lee B, Lee A, Hell JW, Lewis RS, Prakriya M, Feske S. Cavβ1 regulates T cell expansion and apoptosis independently of voltage-gated Ca 2+ channel function. Nat Commun 2022; 13:2033. [PMID: 35440113 PMCID: PMC9018955 DOI: 10.1038/s41467-022-29725-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 03/22/2022] [Indexed: 12/11/2022] Open
Abstract
TCR stimulation triggers Ca2+ signals that are critical for T cell function and immunity. Several pore-forming α and auxiliary β subunits of voltage-gated Ca2+ channels (VGCC) were reported in T cells, but their mechanism of activation remains elusive and their contribution to Ca2+ signaling in T cells is controversial. We here identify CaVβ1, encoded by Cacnb1, as a regulator of T cell function. Cacnb1 deletion enhances apoptosis and impairs the clonal expansion of T cells after lymphocytic choriomeningitis virus (LCMV) infection. By contrast, Cacnb1 is dispensable for T cell proliferation, cytokine production and Ca2+ signaling. Using patch clamp electrophysiology and Ca2+ recordings, we are unable to detect voltage-gated Ca2+ currents or Ca2+ influx in human and mouse T cells upon depolarization with or without prior TCR stimulation. mRNAs of several VGCC α1 subunits are detectable in human (CaV3.3, CaV3.2) and mouse (CaV2.1) T cells, but they lack transcription of many 5' exons, likely resulting in N-terminally truncated and non-functional proteins. Our findings demonstrate that although CaVβ1 regulates T cell function, these effects are independent of VGCC channel activity.
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Affiliation(s)
- Serap Erdogmus
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Axel R Concepcion
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University, Chicago, IL, USA
| | - Ikjot Sidhu
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Anthony Y Tao
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Wenyi Li
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA
| | - Pedro P Rocha
- Unit on Genome Structure and Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Bonnie Huang
- National Institute of Allergy and Infectious Disease, Bethesda, MD, USA
- National Human Genome Research Institute, Bethesda, MD, USA
| | - Ralph Garippa
- Department of Cancer Biology & Genetics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Boram Lee
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Amy Lee
- Department of Neuroscience, University of Texas-Austin, Austin, TX, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Richard S Lewis
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Chicago, IL, USA.
| | - Stefan Feske
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, USA.
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IP3-dependent Ca2+ signals are tightly controlled by Cavβ3, but not by Cavβ1, 2 and 4. Cell Calcium 2022; 104:102573. [DOI: 10.1016/j.ceca.2022.102573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/17/2022] [Accepted: 03/15/2022] [Indexed: 11/18/2022]
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Co-Silencing of the Voltage-Gated Calcium Channel β Subunit and High-Voltage Activated α 1 Subunit by dsRNA Soaking Resulted in Enhanced Defects in Locomotion, Stylet Thrusting, Chemotaxis, Protein Secretion, and Reproduction in Ditylenchus destructor. Int J Mol Sci 2022; 23:ijms23020784. [PMID: 35054970 PMCID: PMC8776034 DOI: 10.3390/ijms23020784] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 12/29/2022] Open
Abstract
The voltage-gated calcium channel (VGCC) β subunit (Cavβ) protein is a kind of cytosolic auxiliary subunit that plays an important role in regulating the surface expression and gating characteristics of high-voltage-activated (HVA) calcium channels. Ditylenchus destructor is an important plant-parasitic nematode. In the present study, the putative Cavβ subunit gene of D. destructor, namely, DdCavβ, was subjected to molecular characterization. In situ hybridization assays showed that DdCavβ was expressed in all nematode tissues. Transcriptional analyses showed that DdCavβ was expressed during each developmental stage of D. destructor, and the highest expression level was recorded in the third-stage juveniles. The crucial role of DdCavβ was verified by dsRNA soaking-mediated RNA interference (RNAi). Silencing of DdCavβ or HVA Cavα1 alone and co-silencing of the DdCavβ and HVA Cavα1 genes resulted in defective locomotion, stylet thrusting, chemotaxis, protein secretion and reproduction in D. destructor. Co-silencing of the HVA Cavα1 and Cavβ subunits showed stronger interference effects than single-gene silencing. This study provides insights for further study of VGCCs in plant-parasitic nematodes.
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Conrad R, Kortzak D, Guzman GA, Miranda-Laferte E, Hidalgo P. Ca V β controls the endocytic turnover of Ca V 1.2 L-type calcium channel. Traffic 2021; 22:180-193. [PMID: 33890356 DOI: 10.1111/tra.12788] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 03/17/2021] [Accepted: 04/17/2021] [Indexed: 01/10/2023]
Abstract
Membrane depolarization activates the multisubunit CaV 1.2 L-type calcium channel initiating various excitation coupling responses. Intracellular trafficking into and out of the plasma membrane regulates the channel's surface expression and stability, and thus, the strength of CaV 1.2-mediated Ca2+ signals. The mechanisms regulating the residency time of the channel at the cell membrane are unclear. Here, we coexpressed the channel core complex CaV 1.2α1 pore-forming and auxiliary CaV β subunits and analyzed their trafficking dynamics from single-particle-tracking trajectories. Speed histograms obtained for each subunit were best fitted to a sum of diffusive and directed motion terms. The same mean speed for the highest-mobility state underlying directed motion was found for all subunits. The frequency of this component increased by covalent linkage of CaV β to CaV 1.2α1 suggesting that high-speed transport occurs in association with CaV β. Selective tracking of CaV 1.2α1 along the postendocytic pathway failed to show the highly mobile state, implying CaV β-independent retrograde transport. Retrograde speeds of CaV 1.2α1 are compatible with myosin VI-mediated backward transport. Moreover, residency time at the cell surface was significantly prolonged when CaV 1.2α1 was covalently linked to CaV β. Thus, CaV β promotes fast transport speed along anterograde trafficking and acts as a molecular switch controlling the endocytic turnover of L-type calcium channels.
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Affiliation(s)
- Rachel Conrad
- Institute of Biological Information Processing (IBI-1), Molecular and Cellular Physiology, Forschungszentrum Jülich, Jülich, Germany
| | - Daniel Kortzak
- Institute of Biological Information Processing (IBI-1), Molecular and Cellular Physiology, Forschungszentrum Jülich, Jülich, Germany
| | - Gustavo A Guzman
- Institute of Biological Information Processing (IBI-1), Molecular and Cellular Physiology, Forschungszentrum Jülich, Jülich, Germany
| | - Erick Miranda-Laferte
- Institute of Biological Information Processing (IBI-1), Molecular and Cellular Physiology, Forschungszentrum Jülich, Jülich, Germany
| | - Patricia Hidalgo
- Institute of Biological Information Processing (IBI-1), Molecular and Cellular Physiology, Forschungszentrum Jülich, Jülich, Germany.,Institute of Biochemistry, Heinrich-Heine University, Düsseldorf, Germany
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7
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Young SM, Veeraraghavan P. Presynaptic voltage-gated calcium channels in the auditory brainstem. Mol Cell Neurosci 2021; 112:103609. [PMID: 33662542 DOI: 10.1016/j.mcn.2021.103609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/06/2021] [Accepted: 02/17/2021] [Indexed: 10/22/2022] Open
Abstract
Sound information encoding within the initial synapses in the auditory brainstem requires reliable and precise synaptic transmission in response to rapid and large fluctuations in action potential (AP) firing rates. The magnitude and location of Ca2+ entry through voltage-gated Ca2+ channels (CaV) in the presynaptic terminal are key determinants in triggering AP-mediated release. In the mammalian central nervous system (CNS), the CaV2.1 subtype is the critical subtype for CNS function, since it is the most efficient CaV2 subtype in triggering AP-mediated synaptic vesicle (SV) release. Auditory brainstem synapses utilize CaV2.1 to sustain fast and repetitive SV release to encode sound information. Therefore, understanding the presynaptic mechanisms that control CaV2.1 localization, organization and biophysical properties are integral to understanding auditory processing. Here, we review our current knowledge about the control of presynaptic CaV2 abundance and organization in the auditory brainstem and impact on the regulation of auditory processing.
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Affiliation(s)
- Samuel M Young
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Otolaryngology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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Segura E, Mehta A, Marsolais M, Quan XR, Zhao J, Sauvé R, Spafford JD, Parent L. An ancestral MAGUK protein supports the modulation of mammalian voltage-gated Ca 2+ channels through a conserved Ca Vβ-like interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183439. [PMID: 32814116 DOI: 10.1016/j.bbamem.2020.183439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/11/2020] [Accepted: 08/03/2020] [Indexed: 01/09/2023]
Abstract
Eukaryote voltage-gated Ca2+ channels of the CaV2 channel family are hetero-oligomers formed by the pore-forming CaVα1 protein assembled with auxiliary CaVα2δ and CaVβ subunits. CaVβ subunits are formed by a Src homology 3 (SH3) domain and a guanylate kinase (GK) domain connected through a HOOK domain. The GK domain binds a conserved cytoplasmic region of the pore-forming CaVα1 subunit referred as the "AID". Herein we explored the phylogenetic and functional relationship between CaV channel subunits in distant eukaryotic organisms by investigating the function of a MAGUK protein (XM_004990081) cloned from the choanoflagellate Salpingoeca rosetta (Sro). This MAGUK protein (Sroβ) features SH3 and GK structural domains with a 25% primary sequence identity to mammalian CaVβ. Recombinant expression of its cDNA with mammalian high-voltage activated Ca2+ channel CaV2.3 in mammalian HEK cells produced robust voltage-gated inward Ca2+ currents with typical activation and inactivation properties. Like CaVβ, Sroβ prevents fast degradation of total CaV2.3 proteins in cycloheximide assays. The three-dimensional homology model predicts an interaction between the GK domain of Sroβ and the AID motif of the pore-forming CaVα1 protein. Substitution of AID residues Trp (W386A) and Tyr (Y383A) significantly impaired co-immunoprecipitation of CaV2.3 with Sroβ and functional upregulation of CaV2.3 currents. Likewise, a 6-residue deletion within the GK domain of Sroβ, similar to the locus found in mammalian CaVβ, significantly reduced peak current density. Altogether our data demonstrate that an ancestor MAGUK protein reconstitutes the biophysical and molecular features responsible for channel upregulation by mammalian CaVβ through a minimally conserved molecular interface.
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Affiliation(s)
- Emilie Segura
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada; Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Amrit Mehta
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Mireille Marsolais
- Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Xin R Quan
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Juan Zhao
- Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Rémy Sauvé
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada
| | - J David Spafford
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Lucie Parent
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada; Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada.
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Guzman GA, Guzman RE, Jordan N, Hidalgo P. A Tripartite Interaction Among the Calcium Channel α 1- and β-Subunits and F-Actin Increases the Readily Releasable Pool of Vesicles and Its Recovery After Depletion. Front Cell Neurosci 2019; 13:125. [PMID: 31130843 PMCID: PMC6509170 DOI: 10.3389/fncel.2019.00125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/13/2019] [Indexed: 11/13/2022] Open
Abstract
Neurotransmitter release is initiated by the influx of Ca2+via voltage-gated calcium channels. The accessory β-subunit (CaVβ) of these channels shapes synaptic transmission by associating with the pore-forming subunit (CaVα1) and up-regulating presynaptic calcium currents. Besides CaVα1, CaVβ interacts with several partners including actin filaments (F-actin). These filaments are known to associate with synaptic vesicles (SVs) at the presynaptic terminals and support their translocation within different pools, but the role of CaVβ/F-actin association on synaptic transmission has not yet been explored. We here study how CaVβ4, the major calcium channel β isoform in mamalian brain, modifies synaptic transmission in concert with F-actin in cultured hippocampal neurons. We analyzed the effect of exogenous CaVβ4 before and after pharmacological disruption of the actin cytoskeleton and dissected calcium channel-dependent and -independent functions by comparing the effects of the wild-type subunit with the one bearing a double mutation that impairs binding to CaVα1. We found that exogenously expressed wild-type CaVβ4 enhances spontaneous and depolarization-evoked excitatory postsynaptic currents (EPSCs) without altering synaptogenesis. CaVβ4 increases the size of the readily releasable pool (RRP) of SVs at resting conditions and accelerates their recovery after depletion. The enhanced neurotransmitter release induced by CaVβ4 is abolished upon disruption of the actin cytoskeleton. The CaVα1 association-deficient CaVβ4 mutant associates with actin filaments, but neither alters postsynaptic responses nor the time course of the RRP recovery. Furthermore, this mutant protein preserves the ability to increase the RRP size. These results indicate that the interplay between CaVβ4 and F-actin also support the recruitment of SVs to the RRP in a CaVα1-independent manner. Our studies show an emerging role of CaVβ in determining SV maturation toward the priming state and its replenishment after release. We envision that this subunit plays a role in coupling exocytosis to endocytosis during the vesicle cycle.
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Affiliation(s)
- Gustavo A Guzman
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Raul E Guzman
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Nadine Jordan
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Patricia Hidalgo
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany.,Institute of Biochemistry, Heinrich-Heine University, Düsseldorf, Germany
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González-Ramírez R, Felix R. Transcriptional regulation of voltage-gated Ca 2+ channels. Acta Physiol (Oxf) 2018; 222. [PMID: 28371478 DOI: 10.1111/apha.12883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/14/2017] [Accepted: 03/21/2017] [Indexed: 12/30/2022]
Abstract
The transcriptional regulation of voltage-gated Ca2+ (CaV ) channels is an emerging research area that promises to improve our understanding of how many relevant physiological events are shaped in the central nervous system, the skeletal muscle and other tissues. Interestingly, a picture of how transcription of CaV channel subunit genes is controlled is evolving with the identification of the promoter regions required for tissue-specific expression and the identification of transcription factors that control their expression. These promoters share several characteristics that include multiple transcriptional start sites, lack of a TATA box and the presence of elements conferring tissue-selective expression. Likewise, changes in CaV channel expression occur throughout development, following ischaemia, seizures or chronic drug administration. This review focuses on insights achieved regarding the control of CaV channel gene expression. To further understand the complexities of expression and to increase the possibilities of detecting CaV channel alterations causing human disease, a deeper knowledge on the structure of the 5' upstream regions of the genes encoding these remarkable proteins will be necessary.
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Affiliation(s)
- R. González-Ramírez
- Departamento de Biología Molecular e Histocompatibilidad; Hospital General ‘Dr. Manuel Gea González’; Secretaría de Salud; Ciudad de México México
| | - R. Felix
- Departmento de Biología Celular; Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN); Ciudad de México México
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Belkacemi A, Hui X, Wardas B, Laschke MW, Wissenbach U, Menger MD, Lipp P, Beck A, Flockerzi V. IP3 Receptor-Dependent Cytoplasmic Ca2+ Signals Are Tightly Controlled by Cavβ3. Cell Rep 2018; 22:1339-1349. [DOI: 10.1016/j.celrep.2018.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/10/2017] [Accepted: 01/03/2018] [Indexed: 12/11/2022] Open
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12
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Rima M, Daghsni M, De Waard S, Gaborit N, Fajloun Z, Ronjat M, Mori Y, Brusés JL, De Waard M. The β 4 subunit of the voltage-gated calcium channel (Cacnb4) regulates the rate of cell proliferation in Chinese Hamster Ovary cells. Int J Biochem Cell Biol 2017; 89:57-70. [PMID: 28587927 DOI: 10.1016/j.biocel.2017.05.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/20/2017] [Accepted: 05/30/2017] [Indexed: 01/03/2023]
Abstract
The β subunits of Voltage-Gated Calcium Channel (VGCC) are cytosolic proteins that interact with the VGCC pore -forming subunit and participate in the trafficking of the channel to the cell membrane and in ion influx regulation. β subunits also exert functions independently of their binding to VGCC by translocation to the cell nucleus including the control of gene expression. Mutations of the neuronal Cacnb4 (β4) subunit are linked to human neuropsychiatric disorders including epilepsy and intellectual disabilities. It is believed that the pathogenic phenotype induced by these mutations is associated with channel-independent functions of the β4 subunit. In this report, we investigated the role of β4 subunit in cell proliferation and cell cycle progression and examined whether these functions could be altered by a pathogenic mutation. To this end, stably transfected Chinese Hamster Ovary (CHO-K1) cells expressing either rat full-length β4 or the rat C-terminally truncated epileptic mutant variant β1-481 were generated. The subcellular localization of both proteins differed significantly. Full-length β4 localizes almost exclusively in the cell nucleus and concentrates into the nucleolar compartment, while the C-terminal-truncated β1-481 subunit was less concentrated within the nucleus and absent from the nucleoli. Cell proliferation was found to be reduced by the expression of β4, while it was unaffected by the epileptic mutant. Also, full-length β4 interfered with cell cycle progression by presumably preventing cells from entering the S-phase via a mechanism that partially involves endogenous B56δ, a regulatory subunit of the phosphatase 2A (PP2A) that binds β4 but not β1-481. Analysis of β4 subcellular distribution during the cell cycle revealed that the protein is highly expressed in the nucleus at the G1/S transition phase and that it is translocated out of the nucleus during chromatin condensation and cell division. These results suggest that nuclear accumulation of β4 at the G1/S transition phase affects the progression into S-phase resulting in a decrease in the rate of cell proliferation. Regulation of the cell cycle exit is a critical step in determining the number of neuronal precursors and neuronal differentiation suggesting that mutations of the β4 subunit could affect neural development and formation of the mature central nervous system.
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Affiliation(s)
- Mohamad Rima
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Azm Center for Research in Biotechnology and its Application, Lebanese University, 1300, Tripoli, Lebanon
| | - Marwa Daghsni
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Université de Tunis El Manar, Faculté de Médecine de Tunis, LR99ES10 Laboratoire de Génétique Humaine, 1007, Tunis, Tunisia
| | - Stephan De Waard
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Université de Nantes, Nantes, F-44000 France
| | - Nathalie Gaborit
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Université de Nantes, Nantes, F-44000 France
| | - Ziad Fajloun
- Azm Center for Research in Biotechnology and its Application, Lebanese University, 1300, Tripoli, Lebanon; Faculty of Sciences III, Lebanese University, 1300, Tripoli, Lebanon
| | - Michel Ronjat
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Université de Nantes, Nantes, F-44000 France
| | - Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Juan L Brusés
- Department of Natural Sciences, Mercy College, Dobbs Ferry, NY 10522, USA
| | - Michel De Waard
- INSERM UMR1087, LabEx Ion Channels Science and Therapeutics, Institut du Thorax, Nantes, F-44000 France; CNRS, UMR6291, Nantes, F-44000 France; Université de Nantes, Nantes, F-44000 France.
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