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Alaklabi AM, Gambeta E, Zamponi GW. Electrophysiological characterization of a Ca V3.1 calcium channel mutation linked to trigeminal neuralgia. Pflugers Arch 2023; 475:711-718. [PMID: 37010626 DOI: 10.1007/s00424-023-02808-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/25/2023] [Accepted: 03/29/2023] [Indexed: 04/04/2023]
Abstract
Trigeminal neuralgia is a rare and debilitating disorder that affects one or more branches of the trigeminal nerve, leading to severe pain attacks and a poor quality of life. It has been reported that the CaV3.1 T-type calcium channel may play an important role in trigeminal pain and a recent study identified a new missense mutation in the CACNA1G gene that encodes the pore forming α1 subunit of the CaV3.1 calcium channel. The mutation leads to a substitution of an Arginine (R) by a Glutamine (Q) at position 706 in the I-II linker region of the channel. Here, we used whole-cell voltage-clamp recordings to evaluate the biophysical properties of CaV3.1 wild-type and R706Q mutant channels expressed in tsA-201 cells. Our data indicate an increase in current density in the R706Q mutant, leading to a gain-of-function effect, without changes in the voltage for half activation. Moreover, voltage clamp using an action potential waveform protocol revealed an increase in the tail current at the repolarization phase in the R706Q mutant. No changes were observed in the voltage-dependence of inactivation. However, the R706Q mutant displayed a faster recovery from inactivation. Hence, the gain-of-function effects in the R706Q CaV3.1 mutant have the propensity to impact pain transmission in the trigeminal system, consistent with a contribution to trigeminal neuralgia pathophysiology.
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Affiliation(s)
- Abdulaziz M Alaklabi
- Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Eder Gambeta
- Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada.
| | - Gerald W Zamponi
- Department of Clinical Neurosciences, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
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2
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Affiliation(s)
- Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
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3
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Ficelova V, Souza IA, Cmarko L, Gandini MA, Stringer RN, Zamponi GW, Weiss N. Functional identification of potential non-canonical N-glycosylation sites within Ca v3.2 T-type calcium channels. Mol Brain 2020; 13:149. [PMID: 33176830 PMCID: PMC7659234 DOI: 10.1186/s13041-020-00697-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/06/2020] [Indexed: 01/14/2023] Open
Abstract
Low-voltage-activated T-type calcium channels are important contributors to nervous system function. Post-translational modification of these channels has emerged as an important mechanism to control channel activity. Previous studies have documented the importance of asparagine (N)-linked glycosylation and identified several asparagine residues within the canonical consensus sequence N-X-S/T that is essential for the expression and function of Cav3.2 channels. Here, we explored the functional role of non-canonical N-glycosylation motifs in the conformation N-X-C based on site directed mutagenesis. Using a combination of electrophysiological recordings and surface biotinylation assays, we show that asparagines N345 and N1780 located in the motifs NVC and NPC, respectively, are essential for the expression of the human Cav3.2 channel in the plasma membrane. Therefore, these newly identified asparagine residues within non-canonical motifs add to those previously reported in canonical sites and suggest that N-glycosylation of Cav3.2 may also occur at non-canonical motifs to control expression of the channel in the plasma membrane. It is also the first study to report the functional importance of non-canonical N-glycosylation motifs in an ion channel.
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Affiliation(s)
- Vendula Ficelova
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Ivana A Souza
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Leos Cmarko
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Maria A Gandini
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Robin N Stringer
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.,Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Norbert Weiss
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague, Czech Republic. .,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.
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4
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Vickstrom CR, Liu X, Zhang Y, Mu L, Kelly TJ, Yan X, Hu MM, Snarrenberg ST, Liu QS. T-Type Calcium Channels Contribute to Burst Firing in a Subpopulation of Medial Habenula Neurons. eNeuro 2020; 7:ENEURO. [PMID: 32719103 DOI: 10.1523/ENEURO.0201-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 11/24/2022] Open
Abstract
Action potential (AP) burst firing caused by the activation of low-voltage-activated T-type Ca2+ channels is a unique mode of neuronal firing. T-type channels have been implicated in diverse physiological and pathophysiological processes, including epilepsy, autism, and mood regulation, but the brain structures involved remain incompletely understood. The medial habenula (MHb) is an epithalamic structure implicated in anxiety-like and withdrawal behavior. Previous studies have shown that MHb neurons fire tonic APs at a frequency of ∼2–10 Hz or display depolarized low-amplitude membrane oscillations. Here, we report in C57BL/6J mice that a subpopulation of MHb neurons are capable of firing transient, high-frequency AP bursts mediated by T-type channels. Burst firing was observed following rebounding from hyperpolarizing current injections or during depolarization from hyperpolarized membrane potentials in ∼20% of MHb neurons. It was rarely observed at baseline but could be evoked in MHb neurons displaying different initial activity states. Further, we show that T-type channel mRNA, in particular Cav3.1, is expressed in the MHb in both cholinergic and substance P-ergic neurons. Pharmacological Cav3 antagonism blocked both burst firing and evoked Ca2+ currents in MHb neurons. Additionally, we observed high-frequency AP doublet firing at sustained depolarized membrane potentials that was independent of T-type channels. Thus, there is a greater diversity of AP firing patterns in MHb neurons than previously identified, including T-type channel-mediated burst firing, which may uniquely contribute to behaviors with relevance to neuropsychiatric disease.
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5
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Abstract
Low-voltage-activated Cav3 calcium channels (T-type) play an essential role in the functioning of the nervous system where they support oscillatory activities that relie on several channel molecular determinants that shape their unique gating properties. In a previous study, we documented the important role of the carboxy proximal region in the functioning of Cav3.3 channels. Here, we explore the ability of a TAT-based cell penetrating peptide containing this carboxy proximal region (TAT-C3P) to modulate the activity of Cav3 channels. We show that chronic application of TAT-C3P on tsA-201 cells expressing Cav3 channels selectively inhibits Cav3.3 channels without affecting Cav3.1 and Cav3.2 channels. Therefore, the TAT-C3P peptide described in this study represents a new tool to address the specific physiological role of Cav3.3 channels, and to potentially enhance our understanding of Cav3.3 in disease.
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Affiliation(s)
- Leos Cmarko
- Institute of Biology and Medical Genetics, First faculty of Medicine, Charles University, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Norbert Weiss
- Institute of Biology and Medical Genetics, First faculty of Medicine, Charles University, Prague, Czech Republic. .,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.
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6
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Abstract
Neuromuscular disorders encompass a wide range of conditions often associated with a genetic component. In the present study, we report a patient with severe infantile-onset amyotrophy in whom two compound heterozygous variants in the gene CACNA1H encoding for Cav3.2 T-type calcium channels were identified. Functional analysis of Cav3.2 variants revealed several alterations of the gating properties of the channel that were in general consistent with a loss-of-channel function. Taken together, these findings suggest that severe congenital amyoplasia may be related to CACNA1H and would represent a new phenotype associated with mutations in this gene.
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Affiliation(s)
- Melissa T Carter
- a Children's Hospital of Eastern Ontario Research Institute , University of Ottawa , Ottawa , Ontario , Canada
| | - Hugh J McMillan
- a Children's Hospital of Eastern Ontario Research Institute , University of Ottawa , Ottawa , Ontario , Canada
| | - Andriy Tomin
- b Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Prague , Czech Republic
| | - Norbert Weiss
- b Institute of Organic Chemistry and Biochemistry , Czech Academy of Sciences , Prague , Czech Republic
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7
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Stringer RN, Lazniewska J, Weiss N. Transcriptomic analysis of glycan-processing genes in the dorsal root ganglia of diabetic mice and functional characterization on Ca v3.2 channels. Channels (Austin) 2020; 14:132-140. [PMID: 32233724 PMCID: PMC7153791 DOI: 10.1080/19336950.2020.1745406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cav3.2 T-type calcium channels play an essential role in the transmission of peripheral nociception in the dorsal root ganglia (DRG) and alteration of Cav3.2 expression is associated with the development of peripheral painful diabetic neuropathy (PDN). Several studies have previously documented the role of glycosylation in the expression and functioning of Cav3.2 and suggested that altered glycosylation of the channel may contribute to the aberrant expression of the channel in diabetic conditions. In this study, we aimed to analyze the expression of glycan-processing genes in DRG neurons from a leptin-deficient genetic mouse model of diabetes (db/db). Transcriptomic analysis revealed that several glycan-processing genes encoding for glycosyltransferases and sialic acid-modifying enzymes were upregulated in diabetic conditions. Functional analysis of these enzymes on recombinant Cav3.2 revealed an unexpected loss-of-function of the channel. Collectively, our data indicate that diabetes is associated with an alteration of the glycosylation machinery in DRG neurons. However, individual action of these enzymes when tested on recombinant Cav3.2 cannot explain the observed upregulation of T-type channels under diabetic conditions. Abbreviations: Galnt16: Polypeptide N-acetylgalactosaminyltransferase 16; B3gnt8: UDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 8; B4galt1: Beta-1,4-galactosyltransferase 1; St6gal1: Beta-galactoside alpha-2,6-sialyltransferase 1; Neu3: Sialidase-3
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Affiliation(s)
- Robin N Stringer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic.,Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Joanna Lazniewska
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
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8
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Stringer RN, Jurkovicova-Tarabova B, Huang S, Haji-Ghassemi O, Idoux R, Liashenko A, Souza IA, Rzhepetskyy Y, Lacinova L, Van Petegem F, Zamponi GW, Pamphlett R, Weiss N. A rare CACNA1H variant associated with amyotrophic lateral sclerosis causes complete loss of Ca v3.2 T-type channel activity. Mol Brain 2020; 13:33. [PMID: 32143681 PMCID: PMC7060640 DOI: 10.1186/s13041-020-00577-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/02/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the progressive loss of cortical, brain stem and spinal motor neurons that leads to muscle weakness and death. A previous study implicated CACNA1H encoding for Cav3.2 calcium channels as a susceptibility gene in ALS. In the present study, two heterozygous CACNA1H variants were identified by whole genome sequencing in a small cohort of ALS patients. These variants were functionally characterized using patch clamp electrophysiology, biochemistry assays, and molecular modeling. A previously unreported c.454GTAC > G variant produced an inframe deletion of a highly conserved isoleucine residue in Cav3.2 (p.ΔI153) and caused a complete loss-of-function of the channel, with an additional dominant-negative effect on the wild-type channel when expressed in trans. In contrast, the c.3629C > T variant caused a missense substitution of a proline with a leucine (p.P1210L) and produced a comparatively mild alteration of Cav3.2 channel activity. The newly identified ΔI153 variant is the first to be reported to cause a complete loss of Cav3.2 channel function. These findings add to the notion that loss-of-function of Cav3.2 channels associated with rare CACNA1H variants may be risk factors in the complex etiology of ALS.
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Affiliation(s)
- Robin N. Stringer
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Sun Huang
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Romane Idoux
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Anna Liashenko
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Ivana A. Souza
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Yuriy Rzhepetskyy
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
| | - Lubica Lacinova
- Center of Biosciences, Institute of Molecular Physiology and Genetics, Academy of Sciences, Bratislava, Slovakia
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Roger Pamphlett
- Discipline of Pathology, Brain and Mind Centre, The University of Sydney, Sydney, NSW Australia
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam 2, 16610 Prague, Czech Republic
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9
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Martínez-Hernández E, Zeglin A, Almazan E, Perissinotti P, He Y, Koob M, Martin JL, Piedras-Rentería ES. KLHL1 Controls Ca V3.2 Expression in DRG Neurons and Mechanical Sensitivity to Pain. Front Mol Neurosci 2020; 12:315. [PMID: 31969803 PMCID: PMC6960199 DOI: 10.3389/fnmol.2019.00315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 12/05/2019] [Indexed: 11/29/2022] Open
Abstract
Dorsal root ganglion (DRG) neurons process pain signaling through specialized nociceptors located in their peripheral endings. It has long been established low voltage-activated (LVA) CaV3.2 calcium channels control neuronal excitability during sensory perception in these neurons. Silencing CaV3.2 activity with antisense RNA or genetic ablation results in anti-nociceptive, anti-hyperalgesic and anti-allodynic effects. CaV3.2 channels are regulated by many proteins (Weiss and Zamponi, 2017), including KLHL1, a neuronal actin-binding protein that stabilizes channel activity by recycling it back to the plasma membrane through the recycling endosome. We explored whether manipulation of KLHL1 levels and thereby function as a CaV3.2 modifier can modulate DRG excitability and mechanical pain transmission or sensitivity to pain. We first assessed the mechanical sensitivity threshold and DRG properties in the KLHL1 KO mouse model. KO DRG neurons exhibited smaller T-type current density compared to WT without significant changes in voltage dependence, as expected in the absence of its modulator. Western blot analysis confirmed CaV3.2 but not CaV3.1, CaV3.3, CaV2.1, or CaV2.2 protein levels were significantly decreased; and reduced neuron excitability and decreased pain sensitivity were also found in the KLHL1 KO model. Analogously, transient down-regulation of KLHL1 levels in WT mice with viral delivery of anti-KLHL1 shRNA also resulted in decreased pain sensitivity. These two experimental approaches confirm KLHL1 as a physiological modulator of excitability and pain sensitivity, providing a novel target to control peripheral pain.
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Affiliation(s)
- Elizabeth Martínez-Hernández
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
- Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Neuroscience Division of the Cardiovascular Institute, Loyola University Chicago, Maywood, IL, United States
| | - Alissa Zeglin
- Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
| | - Erik Almazan
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
| | - Paula Perissinotti
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
- Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Neuroscience Division of the Cardiovascular Institute, Loyola University Chicago, Maywood, IL, United States
| | - Yungui He
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, United States
- Department of Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Michael Koob
- Department of Laboratory Medicine & Pathology, University of Minnesota, Minneapolis, MN, United States
| | - Jody L. Martin
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
- Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Neuroscience Division of the Cardiovascular Institute, Loyola University Chicago, Maywood, IL, United States
| | - Erika S. Piedras-Rentería
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
- Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
- Neuroscience Division of the Cardiovascular Institute, Loyola University Chicago, Maywood, IL, United States
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10
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Asmara H, Micu I, Rizwan AP, Sahu G, Simms BA, Zhang FX, Engbers JDT, Stys PK, Zamponi GW, Turner RW. A T-type channel-calmodulin complex triggers αCaMKII activation. Mol Brain 2017; 10:37. [PMID: 28800734 PMCID: PMC5553682 DOI: 10.1186/s13041-017-0317-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/28/2017] [Indexed: 11/24/2022] Open
Abstract
Calmodulin (CaM) is an important signaling molecule that regulates a vast array of cellular functions by activating second messengers involved in cell function and plasticity. Low voltage-activated calcium channels of the Cav3 family have the important role of mediating low threshold calcium influx, but were not believed to interact with CaM. We find a constitutive association between CaM and the Cav3.1 channel at rest that is lost through an activity-dependent and Cav3.1 calcium-dependent CaM dissociation. Moreover, Cav3 calcium influx is sufficient to activate αCaMKII in the cytoplasm in a manner that depends on an intact Cav3.1 C-terminus needed to support the CaM interaction. Our findings thus establish that T-type channel calcium influx invokes a novel dynamic interaction between CaM and Cav3.1 channels to trigger a signaling cascade that leads to αCaMKII activation.
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Affiliation(s)
- Hadhimulya Asmara
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Ileana Micu
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Arsalan P Rizwan
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Giriraj Sahu
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Brett A Simms
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Fang-Xiong Zhang
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Jordan D T Engbers
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Peter K Stys
- Department of Clinical Neurosciences, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Ray W Turner
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,HRIC 1AA14, University of Calgary, 3330 Hospital Dr. N.W, Calgary, AB, T2N 4N1, Canada.
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11
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Dave V, Manchanda R. A computational model of the [Formula: see text] transients and influence of buffering in guinea pig urinary bladder smooth muscle cells. J Bioinform Comput Biol 2017; 15:1750011. [PMID: 28506097 DOI: 10.1142/s0219720017500111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many cellular events including electrical activity and muscle contraction are regulated and coordinated by intracellular [Formula: see text] concentration ([[Formula: see text]][Formula: see text]. In detrusor smooth muscle (DSM) cells, [[Formula: see text]]i is normally maintained at very low levels and rises transiently during signalling processes as a result of (i) influx from the extracellular space (mainly via L-type and T-type [Formula: see text] channels) and (ii) [Formula: see text] release from sarcoplasmic reticulum (SR) into the cytoplasm. Intracellular [Formula: see text] buffers, both fixed and diffusible, play a vital role in shaping the radial distribution of free [Formula: see text]. Our aim, in the work presented here, is to develop a mathematical model of [Formula: see text] buffering and diffusion and to generate [Formula: see text] transient in guinea pig DSM cells. The [Formula: see text] transient is generated using inward [Formula: see text] current that arises following voltage clamp and mediated by L-type and T-type [Formula: see text] channels. [Formula: see text] transient is obtained for different radial locations (or shells) of the DSM cytosol. This modeling study explores the levels of [[Formula: see text]]i achieved near the plasma membrane and in deeper locations. The [Formula: see text] transient generated in our model shows a high degree of similarity with experimental findings in terms of amplitude, duration and half-decay time. A number of different buffer properties such as concentration and mobility are tested for their effect on amplitude and shape of [Formula: see text] transient. The presence of fast buffer concentration in the cytosol markedly delays the rise of [[Formula: see text]]i in the core of the cell. Increase in the mobility of fast buffer slightly speeds up the redistribution of [Formula: see text]. To explore the model further, the role of plasma membrane [Formula: see text]-ATPase (PMCA) pump, sarcoplasmic/endoplasmic reticulum [Formula: see text]-ATPase (SERCA) pump and sodium calcium exchanger (NCX) on [Formula: see text] transient is studied and it is suggested that NCX may be of primary importance for the immediate lowering of [[Formula: see text]]i during the falling phase of a [Formula: see text] transient in DSM cells.
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Affiliation(s)
- Vijay Dave
- * Biosciences and Bioengineering Department, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India.,† Biomedical Engineering Department, Government Polytechnic, Gandhinagar 382026, Gujarat, India
| | - Rohit Manchanda
- * Biosciences and Bioengineering Department, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
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12
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Abstract
L-type voltage gated Ca2+ channels are considered to be the primary source of calcium influx during the myogenic response. However, many vascular beds also express T-type voltage gated Ca2+ channels. Recent studies suggest that these channels may also play a role in autoregulation. At low pressures (40-80 mmHg) T-type channels affect myogenic responses in cerebral and mesenteric vascular beds. T-type channels also seem to be involved in skeletal muscle autoregulation. This review discusses the expression and role of T-type voltage gated Ca2+ channels in the autoregulation of several different vascular beds. Lack of specific pharmacological inhibitors has been a huge challenge in the field. Now the research has been strengthened by genetically modified models such as mice lacking expression of T-type voltage gated Ca2+ channels (CaV3.1 and CaV3.2). Hopefully, these new tools will help further elucidate the role of voltage gated T-type Ca2+ channels in autoregulation and vascular function.
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Affiliation(s)
- Lars Jørn Jensen
- a Departments of Veterinary Clinical and Animal Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Morten Schak Nielsen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Max Salomonsson
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Charlotte Mehlin Sørensen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
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13
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Rzhepetskyy Y, Lazniewska J, Blesneac I, Pamphlett R, Weiss N. CACNA1H missense mutations associated with amyotrophic lateral sclerosis alter Cav3.2 T-type calcium channel activity and reticular thalamic neuron firing. Channels (Austin) 2016; 10:466-77. [PMID: 27331657 DOI: 10.1080/19336950.2016.1204497] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. In a recent study by Steinberg and colleagues, 2 recessive missense mutations were identified in the Cav3.2 T-type calcium channel gene (CACNA1H), in a family with an affected proband (early onset, long duration ALS) and 2 unaffected parents. We have introduced and functionally characterized these mutations using transiently expressed human Cav3.2 channels in tsA-201 cells. Both of these mutations produced mild but significant changes on T-type channel activity that are consistent with a loss of channel function. Computer modeling in thalamic reticular neurons suggested that these mutations result in decreased neuronal excitability of thalamic structures. Taken together, these findings implicate CACNA1H as a susceptibility gene in amyotrophic lateral sclerosis.
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Affiliation(s)
- Yuriy Rzhepetskyy
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
| | - Joanna Lazniewska
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
| | - Iulia Blesneac
- b Nuffield Department of Clinical Neurosciences , John Radcliffe Hospital, University of Oxford , Oxford , UK
| | - Roger Pamphlett
- c The Stacey MND Laboratory, Discipline of Pathology, The University of Sydney , Sydney , NSW , Australia
| | - Norbert Weiss
- a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Prague , Czech Republic
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14
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Ondacova K, Karmazinova M, Lazniewska J, Weiss N, Lacinova L. Modulation of Cav3.2 T-type calcium channel permeability by asparagine-linked glycosylation. Channels (Austin) 2016; 10:175-84. [PMID: 26745591 DOI: 10.1080/19336950.2016.1138189] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Low-voltage-gated T-type calcium channels are expressed throughout the nervous system where they play an essential role in shaping neuronal excitability. Defects in T-type channel expression have been linked to various neuronal disorders including neuropathic pain and epilepsy. Currently, little is known about the cellular mechanisms controlling the expression and function of T-type channels. Asparagine-linked glycosylation has recently emerged as an essential signaling pathway by which the cellular environment can control expression of T-type channels. However, the role of N-glycans in the conducting function of T-type channels remains elusive. In the present study, we used human Cav3.2 glycosylation-deficient channels to assess the role of N-glycosylation on the gating of the channel. Patch-clamp recordings of gating currents revealed that N-glycans attached to hCav3.2 channels have a minimal effect on the functioning of the channel voltage-sensor. In contrast, N-glycosylation on specific asparagine residues may have an essential role in the conducting function of the channel by enhancing the channel permeability and / or the pore opening of the channel. Our data suggest that modulation of N-linked glycosylation of hCav3.2 channels may play an important physiological role, and could also support the alteration of T-type currents observed in disease states.
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Affiliation(s)
- Katarina Ondacova
- a Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences , Bratislava , Slovakia
| | - Maria Karmazinova
- a Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences , Bratislava , Slovakia
| | - Joanna Lazniewska
- b Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i. , Prague , Czech Republic
| | - Norbert Weiss
- b Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i. , Prague , Czech Republic
| | - Lubica Lacinova
- a Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences , Bratislava , Slovakia
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15
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Bernhardt ML, Zhang Y, Erxleben CF, Padilla-Banks E, McDonough CE, Miao YL, Armstrong DL, Williams CJ. CaV3.2 T-type channels mediate Ca²⁺ entry during oocyte maturation and following fertilization. J Cell Sci 2015; 128:4442-52. [PMID: 26483387 DOI: 10.1242/jcs.180026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/12/2015] [Indexed: 01/05/2023] Open
Abstract
Initiation of mouse embryonic development depends upon a series of fertilization-induced rises in intracellular Ca(2+). Complete egg activation requires influx of extracellular Ca(2+); however, the channels that mediate this influx remain unknown. Here, we tested whether the α1 subunit of the T-type channel CaV3.2, encoded by Cacna1h, mediates Ca(2+) entry into oocytes. We show that mouse eggs express a robust voltage-activated Ca(2+) current that is completely absent in Cacna1h(-/-) eggs. Cacna1h(-/-) females have reduced litter sizes, and careful analysis of Ca(2+) oscillation patterns in Cacna1h(-/-) eggs following in vitro fertilization (IVF) revealed reductions in first transient length and oscillation persistence. Total and endoplasmic reticulum (ER) Ca(2+) stores were also reduced in Cacna1h(-/-) eggs. Pharmacological inhibition of CaV3.2 in wild-type CF-1 strain eggs using mibefradil or pimozide reduced Ca(2+) store accumulation during oocyte maturation and reduced Ca(2+) oscillation persistence, frequency and number following IVF. Overall, these data show that CaV3.2 T-type channels have prev8iously unrecognized roles in supporting the meiotic-maturation-associated increase in ER Ca(2+) stores and mediating Ca(2+) influx required for the activation of development.
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Affiliation(s)
- Miranda L Bernhardt
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yingpei Zhang
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Christian F Erxleben
- Neurobiology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Elizabeth Padilla-Banks
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Caitlin E McDonough
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yi-Liang Miao
- Key Laboratory of Animal Genetics, Breeding, and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - David L Armstrong
- Neurobiology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Carmen J Williams
- Reproductive and Developmental Biology Laboratory, National Institutes of Health, Research Triangle Park, NC 27709, USA
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16
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Weiss N. Should they team up to make your brain clock? Neurobiol Aging 2015; 36:2184-5. [PMID: 25911277 DOI: 10.1016/j.neurobiolaging.2015.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 03/28/2015] [Indexed: 11/24/2022]
Abstract
Large-conductance calcium-activated potassium channels (BK channels) are important regulators of neuronal excitability in the mammalian nervous system. BK channels are activated by changes in membrane electrical potential and intracellular calcium concentration and play a key role in shaping neuronal action potential. Indeed, under typical physiological conditions, opening of BK channels allows potassium ions to flow outside of the cell leading to membrane repolarization and fast afterhyperpolarization, thus controlling cellular excitability. These aspects are of direct relevance to a new study by Farajnia et al., 2015, reported in this issue of Neurobiology of Aging, on the role of BK channels in aging circadian clock neurons.
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17
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Perissinotti PP, Ethington EG, Cribbs L, Koob MD, Martin J, Piedras-Rentería ES. Down-regulation of endogenous KLHL1 decreases voltage-gated calcium current density. Cell Calcium 2014; 55:269-80. [PMID: 24703904 DOI: 10.1016/j.ceca.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 03/04/2014] [Accepted: 03/09/2014] [Indexed: 10/25/2022]
Abstract
The actin-binding protein Kelch-like 1 (KLHL1) can modulate voltage-gated calcium channels in vitro. KLHL1 interacts with actin and with the pore-forming subunits of Cav2.1 and CaV3.2 calcium channels, resulting in up-regulation of P/Q and T-type current density. Here we tested whether endogenous KLHL1 modulates voltage gated calcium currents in cultured hippocampal neurons by down-regulating the expression of KLHL1 via adenoviral delivery of shRNA targeted against KLHL1 (shKLHL1). Control adenoviruses did not affect any of the neuronal properties measured, yet down-regulation of KLHL1 resulted in HVA current densities ~68% smaller and LVA current densities 44% smaller than uninfected controls, with a concomitant reduction in α(1A) and α(1H) protein levels. Biophysical analysis and western blot experiments suggest Ca(V)3.1 and 3.3 currents are also present in shKLHL1-infected neurons. Synapsin I levels, miniature postsynaptic current frequency, and excitatory and inhibitory synapse number were reduced in KLHL1 knockdown. This study corroborates the physiological role of KLHL1 as a calcium channel modulator and demonstrates a novel, presynaptic role.
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Affiliation(s)
- Paula P Perissinotti
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Elizabeth G Ethington
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Leanne Cribbs
- Office of Research Services, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Michael D Koob
- Institute for Translational Neuroscience, Department of Lab Medicine & Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jody Martin
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Erika S Piedras-Rentería
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
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18
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Abstract
Perhaps one of the most remarkable features of T-type calcium channels is their low-threshold of activation that makes these channels important candidates for calcium entry near the resting membrane potential of neurons. Hence, they mediate low-threshold burst discharges that occur during different forms of neuronal rhythmogenesis, but play also important roles in sensory transmission, as well as hormone and neurotransmitter release. Additionally, they have been implicated in an increasing number of neuronal pathologies including neuropathy, autism spectrum disorders and some forms of epilepsy. More recently, an implication of T-type calcium channel in the processing of Amyloid Precursor Protein was documented, with possible implication in the pathogenesis of Alzheimer’s disease.
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Affiliation(s)
- Juliane Proft
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague, Czech Republic
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague, Czech Republic
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