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El Ghaleb Y, Flucher BE. Ca V3.3 Channelopathies. Handb Exp Pharmacol 2023; 279:263-288. [PMID: 36592228 DOI: 10.1007/164_2022_631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CaV3.3 is the third member of the low-voltage-activated calcium channel family and the last to be recognized as disease gene. Previously, CACNA1I, the gene encoding CaV3.3, had been described as schizophrenia risk gene. More recently, de novo missense mutations in CACNA1I were identified in patients with variable degrees of neurodevelopmental disease with and without epilepsy. Their functional characterization indicated gain-of-function effects resulting in increased calcium load and hyperexcitability of neurons expressing CaV3.3. The amino acids mutated in the CaV3.3 disease variants are located in the vicinity of the channel's activation gate and thus are classified as gate-modifying channelopathy mutations. A persistent calcium leak during rest and prolonged calcium spikes due to increased voltage sensitivity of activation and slowed kinetics of channel inactivation, respectively, may be causal for the neurodevelopmental defects. The prominent expression of CaV3.3 in thalamic reticular nucleus neurons and its essential role in generating the rhythmic thalamocortical network activity are consistent with a role of the mutated channels in the etiology of epileptic seizures and thus suggest T-type channel blockers as a viable treatment option.
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Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
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2
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Mustafá ER, Gambeta E, Stringer RN, Souza IA, Zamponi GW, Weiss N. Electrophysiological and computational analysis of Ca v3.2 channel variants associated with familial trigeminal neuralgia. Mol Brain 2022; 15:91. [PMID: 36397158 PMCID: PMC9670400 DOI: 10.1186/s13041-022-00978-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 11/02/2022] [Indexed: 11/18/2022] Open
Abstract
Trigeminal neuralgia (TN) is a rare form of chronic neuropathic pain characterized by spontaneous or elicited paroxysms of electric shock-like or stabbing pain in a region of the face. While most cases occur in a sporadic manner and are accompanied by intracranial vascular compression of the trigeminal nerve root, alteration of ion channels has emerged as a potential exacerbating factor. Recently, whole exome sequencing analysis of familial TN patients identified 19 rare variants in the gene CACNA1H encoding for Cav3.2T-type calcium channels. An initial analysis of 4 of these variants pointed to a pathogenic role. In this study, we assessed the electrophysiological properties of 13 additional TN-associated Cav3.2 variants expressed in tsA-201 cells. Our data indicate that 6 out of the 13 variants analyzed display alteration of their gating properties as evidenced by a hyperpolarizing shift of their voltage dependence of activation and/or inactivation resulting in an enhanced window current supported by Cav3.2 channels. An additional variant enhanced the recovery from inactivation. Simulation of neuronal electrical membrane potential using a computational model of reticular thalamic neuron suggests that TN-associated Cav3.2 variants could enhance neuronal excitability. Altogether, the present study adds to the notion that ion channel polymorphisms could contribute to the etiology of some cases of TN and further support a role for Cav3.2 channels.
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Affiliation(s)
- Emilio R. Mustafá
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Eder Gambeta
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Robin N. Stringer
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic ,grid.418095.10000 0001 1015 3316Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Ivana A. Souza
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Gerald W. Zamponi
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, Alberta Children’s Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Norbert Weiss
- grid.4491.80000 0004 1937 116XDepartment of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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Cmarko L, Weiss N. Selective inhibition of neuronal Ca v3.3 T-type calcium channels by TAT-based channel peptide. Mol Brain 2020; 13:95. [PMID: 32560664 PMCID: PMC7304182 DOI: 10.1186/s13041-020-00636-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 06/12/2020] [Indexed: 02/08/2023] Open
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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Jurkovicova-Tarabova B, Cmarko L, Rehak R, Zamponi GW, Lacinova L, Weiss N. Identification of a molecular gating determinant within the carboxy terminal region of Ca v3.3 T-type channels. Mol Brain 2019; 12:34. [PMID: 30961646 PMCID: PMC6454634 DOI: 10.1186/s13041-019-0457-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 04/01/2019] [Indexed: 01/02/2023] Open
Abstract
The physiological functions controlled by T-type channels are intrinsically dependent on their gating properties, and alteration of T-type channel activity is linked to several human disorders. Therefore, it is essential to develop a clear understanding of the structural determinants responsible for the unique gating features of T-type channels. Here, we have investigated the specific role of the carboxy terminal region by creating a series a deletion constructs expressed in tsA-201 cells and analyzing them by patch clamp electrophysiology. Our data reveal that the proximal region of the carboxy terminus contains a structural determinant essential for shaping several gating aspects of Cav3.3 channels, including voltage-dependence of activation and inactivation, inactivation kinetics, and coupling between the voltage sensing and the pore opening of the channel. Altogether, our data are consistent with a model in which the carboxy terminus stabilizes the channel in a closed state.
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Affiliation(s)
| | - Leos Cmarko
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic
| | - Renata Rehak
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Lubica Lacinova
- Center of Biosciences, Institute of Molecular Physiology and Genetics, Academy of Sciences, Bratislava, Slovakia
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague, Czech Republic
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Wang D, Ragnarsson L, Lewis RJ. T-type Calcium Channels in Health and Disease. Curr Med Chem 2018; 27:3098-3122. [PMID: 30277145 DOI: 10.2174/0929867325666181001112821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022]
Abstract
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific "window current", T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
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Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
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Karmažínová M, Jašková K, Griac P, Perez-Reyes E, Lacinová Ľ. Contrasting the roles of the I-II loop gating brake in CaV3.1 and CaV3.3 calcium channels. Pflugers Arch 2015; 467:2519-27. [PMID: 26306541 DOI: 10.1007/s00424-015-1728-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/16/2015] [Accepted: 08/18/2015] [Indexed: 01/23/2023]
Abstract
Low-voltage-activated CaV3 channels are distinguished among other voltage-activated calcium channels by the most negative voltage activation threshold. The voltage dependence of current activation is virtually identical in all three CaV3 channels while the current kinetics of the CaV3.3 current is one order slower than that of the CaV3.1 and CaV3.2 channels. We have analyzed the voltage dependence and kinetics of charge (Q) movement in human recombinant CaV3.3 and CaV3.1 channels. The voltage dependence of voltage sensor activation (Qon-V) of the CaV3.3 channel was significantly shifted with respect to that of the CaV3.1 channel by +18.6 mV and the kinetic of Qon activation in the CaV3.3 channel was significantly slower than that of the CaV3.1 channel. Removal of the gating brake in the intracellular loop connecting repeats I and II in the CaV3.3 channel in the ID12 mutant channel shifted the Qon-V relation to a value even more negative than that for the CaV3.1 channel. The kinetic of Qon activation was not significantly different between ID12 and CaV3.1 channels. Deletion of the gating brake in the CaV3.1 channel resulted in a GD12 channel with the voltage dependence of the gating current activation significantly shifted toward more negative potentials. The Qon kinetic was not significantly altered. ID12 and GD12 mutants did not differ significantly in voltage dependence nor in the kinetic of voltage sensor activation. In conclusion, the putative gating brake in the intracellular loop connecting repeats I and II controls the gating current of the CaV3 channels. We suggest that activation of the voltage sensor in domain I is limiting both the voltage dependence and the kinetics of CaV3 channel activation.
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Affiliation(s)
- Mária Karmažínová
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 833 34, Bratislava, Slovakia
| | - Katarína Jašková
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 833 34, Bratislava, Slovakia
| | - Peter Griac
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ľubica Lacinová
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 833 34, Bratislava, Slovakia.
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Senatore A, Spafford JD. Gene transcription and splicing of T-type channels are evolutionarily-conserved strategies for regulating channel expression and gating. PLoS One 2012; 7:e37409. [PMID: 22719839 PMCID: PMC3376122 DOI: 10.1371/journal.pone.0037409] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/19/2012] [Indexed: 01/17/2023] Open
Abstract
T-type calcium channels operate within tightly regulated biophysical constraints for supporting rhythmic firing in the brain, heart and secretory organs of invertebrates and vertebrates. The snail T-type gene, LCa(v)3 from Lymnaea stagnalis, possesses alternative, tandem donor splice sites enabling a choice of a large exon 8b (201 aa) or a short exon 25c (9 aa) in cytoplasmic linkers, similar to mammalian homologs. Inclusion of optional 25c exons in the III-IV linker of T-type channels speeds up kinetics and causes hyperpolarizing shifts in both activation and steady-state inactivation of macroscopic currents. The abundant variant lacking exon 25c is the workhorse of embryonic Ca(v)3 channels, whose high density and right-shifted activation and availability curves are expected to increase pace-making and allow the channels to contribute more significantly to cellular excitation in prenatal tissue. Presence of brain-enriched, optional exon 8b conserved with mammalian Ca(v)3.1 and encompassing the proximal half of the I-II linker, imparts a ~50% reduction in total and surface-expressed LCa(v)3 channel protein, which accounts for reduced whole-cell calcium currents of +8b variants in HEK cells. Evolutionarily conserved optional exons in cytoplasmic linkers of Ca(v)3 channels regulate expression (exon 8b) and a battery of biophysical properties (exon 25c) for tuning specialized firing patterns in different tissues and throughout development.
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Lee SS, Kang HW, Park JY, Lee JH. DTNB oxidation effects on T-type Ca2+channel isoforms. Anim Cells Syst (Seoul) 2011. [DOI: 10.1080/19768354.2011.577560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Liu XB, Murray KD, Jones EG. Low-threshold calcium channel subunit Ca(v) 3.3 is specifically localized in GABAergic neurons of rodent thalamus and cerebral cortex. J Comp Neurol 2011; 519:1181-95. [PMID: 21344408 DOI: 10.1002/cne.22567] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Relatively little is known about the subcellular localization of low threshold Ca²+ channels (T-channels) in the brain. Using immunocytochemical labeling and preembedding immunoperoxidase and silver-enhanced immunogold electron microscopy, we localized T-channel subunit Ca(v) 3.3 in rodent cerebral cortex and thalamus. Double immunofluorescent staining demonstrated that Ca(v) 3.3-labeled neurons in cerebral cortex are a subgroup of GABAergic interneurons that coexpress calbindin and in half of the cases parvalbumin. In the thalamus, virtually all reticular nucleus (RTN) neurons were immunopositive for Ca(v) 3.3, while neurons in dorsal thalamic nuclei were nonimmunoreactive. At the electron microscopic (EM) level, in cortical layers IV-V and RTN neurons, Ca(v) 3.3 immunoreactivity was mainly associated with membranes of dendrites but with some localization in cytoplasm. None was found in axon terminals. In cortex, ≈73% of immunogold particles were present in close proximity to synaptic contacts (<0.5 μm from the postsynaptic density), while 27% were distributed along membranes at extrasynaptic sites (>0.5 μm from the postsynaptic density). In RTN, ≈57% particles were evenly distributed along perisynaptic membranes and the remaining 43% of particles were diffusely localized at extrasynaptic membranes. The density of particles along the dendritic membranes of cortical neurons was 40% higher than in RTN neurons. These results suggest that Ca(v) 3.3 plays a role in regulating GABAergic neurons whose actions underlie thalamocortical rhythmicity.
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Affiliation(s)
- Xiao-Bo Liu
- Center for Neuroscience, University of California at Davis, Davis, California 95618, USA
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