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Heigl T, Netzer MA, Zanetti L, Ganglberger M, Fernández-Quintero ML, Koschak A. Characterization of two pathological gating-charge substitutions in Cav1.4 L-type calcium channels. Channels (Austin) 2023; 17:2192360. [PMID: 36943941 PMCID: PMC10038055 DOI: 10.1080/19336950.2023.2192360] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/14/2023] [Indexed: 03/23/2023] Open
Abstract
Cav1.4 L-type calcium channels are predominantly expressed at the photoreceptor terminals and in bipolar cells, mediating neurotransmitter release. Mutations in its gene, CACNA1F, can cause congenital stationary night-blindness type 2 (CSNB2). Due to phenotypic variability in CSNB2, characterization of pathological variants is necessary to better determine pathological mechanism at the site of action. A set of known mutations affects conserved gating charges in the S4 voltage sensor, two of which have been found in male CSNB2 patients. Here, we describe two disease-causing Cav1.4 mutations with gating charge neutralization, exchanging an arginine 964 with glycine (RG) or arginine 1288 with leucine (RL). In both, charge neutralization was associated with a reduction channel expression also reflected in smaller ON gating currents. In RL channels, the strong decrease in whole-cell current densities might additionally be explained by a reduction of single-channel currents. We further identified alterations in their biophysical properties, such as a hyperpolarizing shift of the activation threshold and an increase in slope factor of activation and inactivation. Molecular dynamic simulations in RL substituted channels indicated water wires in both, resting and active, channel states, suggesting the development of omega (ω)currents as a new pathological mechanism in CSNB2. This sum of the respective channel property alterations might add to the differential symptoms in patients beside other factors, such as genomic and environmental deviations.
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Affiliation(s)
- Thomas Heigl
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Innsbruck, Austria
| | - Michael A. Netzer
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Innsbruck, Austria
| | - Lucia Zanetti
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Innsbruck, Austria
| | - Matthias Ganglberger
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Innsbruck, Austria
| | - Monica L. Fernández-Quintero
- Institute of General, Inorganic and Theoretical Chemistry, Center for Chemistry and Biomedicine, University of Innsbruck, Innsbruck, Austria
- Division of Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Vienna, Vienna, Austria
| | - Alexandra Koschak
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Innsbruck, Austria
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Zhou W, Zhao P, Gao J, Zhang Y. A novel CACNA1S gene variant in a child with hypokalemic periodic paralysis: a case report and literature review. BMC Pediatr 2023; 23:500. [PMID: 37784084 PMCID: PMC10544472 DOI: 10.1186/s12887-023-04326-1] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 09/24/2023] [Indexed: 10/04/2023] Open
Abstract
BACKGROUND The CACNA1S gene encodes the alpha 1 S-subunit of the voltage-gated calcium channel, which is primarily expressed in the skeletal muscle cells. Pathogenic variants of CACNA1S can cause hypokalemic periodic paralysis (HypoPP), malignant hyperthermia susceptibility, and congenital myopathy. We aimed to study the clinical and molecular features of a male child with a CACNA1S variant and depict the molecular sub-regional characteristics of different phenotypes associated with CACNA1S variants. CASE PRESENTATION We presented a case of HypoPP with recurrent muscle weakness and hypokalemia. Genetic analyses of the family members revealed that the proband had a novel c.497 C > A (p.Ala166Asp) variant of CACNA1S, which was inherited from his father. The diagnosis of HypoPP was established in the proband as he met the consensus diagnostic criteria. The patient and his parents were informed to avoid the classical triggers of HypoPP. The attacks of the patient are prevented by lifestyle changes and nutritional counseling. We also showed the molecular sub-regional location of the variants of CACNA1S which was associated with different phenotypes. CONCLUSIONS Our results identified a new variant of CACNA1S and expanded the spectrum of variants associated with HypoPP. Early genetic diagnosis can help avoid diagnostic delays, perform genetic counseling, provide proper treatment, and reduce morbidity and mortality.
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Affiliation(s)
- Wen Zhou
- Department of Pediatrics, People's Hospital of Jinping Miao, Yao and Dai Autonomous County, Honghe Prefecture, Yunnan Province, China
| | - Peilin Zhao
- Department of Pediatrics, People's Hospital of Jinping Miao, Yao and Dai Autonomous County, Honghe Prefecture, Yunnan Province, China
| | - Jian Gao
- Department of Pediatrics, People's Hospital of Jinping Miao, Yao and Dai Autonomous County, Honghe Prefecture, Yunnan Province, China
| | - Yunjian Zhang
- Department of Neurology, National Children's Medical Center, Children's Hospital of Fudan University, 399 Wanyuan Road, Minhang District, Shanghai, 201102, China.
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Catacuzzeno L, Conti F, Franciolini F. Fifty years of gating currents and channel gating. J Gen Physiol 2023; 155:e202313380. [PMID: 37410612 PMCID: PMC10324510 DOI: 10.1085/jgp.202313380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 06/02/2023] [Indexed: 07/08/2023] Open
Abstract
We celebrate this year the 50th anniversary of the first electrophysiological recordings of the gating currents from voltage-dependent ion channels done in 1973. This retrospective tries to illustrate the context knowledge on channel gating and the impact gating-current recording had then, and how it continued to clarify concepts, elaborate new ideas, and steer the scientific debate in these 50 years. The notion of gating particles and gating currents was first put forward by Hodgkin and Huxley in 1952 as a necessary assumption for interpreting the voltage dependence of the Na and K conductances of the action potential. 20 years later, gating currents were actually recorded, and over the following decades have represented the most direct means of tracing the movement of the gating charges and gaining insights into the mechanisms of channel gating. Most work in the early years was focused on the gating currents from the Na and K channels as found in the squid giant axon. With channel cloning and expression on heterologous systems, other channels as well as voltage-dependent enzymes were investigated. Other approaches were also introduced (cysteine mutagenesis and labeling, site-directed fluorometry, cryo-EM crystallography, and molecular dynamics [MD] modeling) to provide an integrated and coherent view of voltage-dependent gating in biological macromolecules. The layout of this retrospective reflects the past 50 years of investigations on gating currents, first addressing studies done on Na and K channels and then on other voltage-gated channels and non-channel structures. The review closes with a brief overview of how the gating-charge/voltage-sensor movements are translated into pore opening and the pathologies associated with mutations targeting the structures involved with the gating currents.
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Affiliation(s)
- Luigi Catacuzzeno
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Franco Conti
- Department of Physics, University of Genova, Genova, Italy
| | - Fabio Franciolini
- Department of Chemistry Biology and Biotechnology, University of Perugia, Perugia, Italy
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Shibano M, Kubota T, Kokubun N, Miyaji Y, Kuriki H, Ito Y, Hamanoue H, Takahashi MP. Periodic paralysis due to cumulative effects of rare variants in SCN4A with small functional alterations. Muscle Nerve 2022; 66:757-761. [PMID: 36116128 DOI: 10.1002/mus.27725] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 09/07/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022]
Abstract
INTRODUCTION/AIMS Mutations in the SCN4A gene encoding a voltage-gated sodium channel (Nav1.4) cause hyperkalemic periodic paralysis (HyperPP) and hypokalemic periodic paralysis (HypoPP). Typically, both HyperPP and HypoPP are considered as monogenic disorders caused by a missense mutation with a large functional effect. However, a few cases with atypical periodic paralysis phenotype have been caused by multiple mutations in ion-channel genes expressed in skeletal muscles. In this study we investigated the underlying pathogenic mechanisms in such cases. METHODS We clinically assessed two families: proband 1 with HyperPP and proband 2 with atypical periodic paralysis with hypokalemia. Genetic analyses were performed by next-generation sequencing and conventional Sanger sequencing, followed by electrophysiological analyses of the mutant Nav1.4 channels expressed in human embryonic kidney 293T (HEK293T) cells using the whole-cell patch-clamp technique. RESULTS In proband 1, K880del was identified in the SCN4A gene. In proband 2, K880del and a novel mutation, R1639H, were identified in the same allele of the SCN4A gene. Functional analyses revealed that the K880del in SCN4A has a weak functional effect on hNav1.4, increasing the excitability of the sarcolemma, which could represent a potential pathogenic factor. Although R1639H alone did not reveal functional changes strong enough to be pathogenic, Nav1.4 with both K880del and R1639H showed enhanced activation compared with K880del alone, indicating that R1639H may modify the hNav1.4 channel function. DISCUSSION A cumulative effect of variants with small functional alterations may be considered as the underpinning oligogenic pathogenic mechanisms for the unusual phenotype of periodic paralysis.
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Affiliation(s)
- Maki Shibano
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tomoya Kubota
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Norito Kokubun
- Department of Neurology, Dokkyo Medical University, Shimotsuga, Japan
| | - Yosuke Miyaji
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroko Kuriki
- Department of Clinical Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yuzuru Ito
- Department of Endocrinology and Metabolism, Yokohama City University Medical Center, Yokohama, Japan
| | - Haruka Hamanoue
- Department of Clinical Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Masanori P Takahashi
- Clinical Neurophysiology, Department of Clinical Laboratory and Biomedical Sciences, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
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DiFranco M, Cannon S. Voltage-Dependent Ca 2+ Release Is Impaired in Hypokalemic Periodic Paralysis Caused by Ca V1.1-R528H but not by Na V1.4-R669H. Am J Physiol Cell Physiol 2022; 323:C478-C485. [PMID: 35759432 PMCID: PMC9359662 DOI: 10.1152/ajpcell.00209.2022] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypokalemic periodic paralysis (HypoPP) is a channelopathy of skeletal muscle caused by missense mutations in the voltage sensor domains (usually at an arginine of the S4 segment) of the CaV1.1 calcium channel or of the NaV1.4 sodium channel. The primary clinical manifestation is recurrent attacks of weakness, resulting from impaired excitability of anomalously depolarized fibers containing leaky mutant channels. While the ictal loss of fiber excitability is sufficient to explain the acute episodes of weakness, a deleterious change in voltage sensor function for CaV1.1 mutant channels may also compromise excitation-contraction coupling (EC-coupling). We used the low-affinity Ca2+ indicator OGN-5 to assess voltage-dependent Ca2+-release as a measure of EC-coupling for our knock-in mutant mouse models of HypoPP. The peak in fibers isolated from CaV1.1-R528H mice was about two-thirds of the amplitude observed in WT mice; whereas in HypoPP fibers from NaV1.4-R669H mice the was indistinguishable from WT. No difference in the voltage dependence of from WT was observed for fibers from either HypoPP mouse model. Because late-onset permanent muscle weakness is more severe for CaV1.1-associated HypoPP than for NaV1.4, we propose the reduced Ca2+-release for CaV1.1-R528H mutant channels may increase the susceptibility to fixed myopathic weakness. In contrast the episodes of transient weakness are similar for CaV1.1- and NaV1.4-associated HypoPP, consistent with the notion that acute attacks of weakness are primarily caused by leaky channels and are not a consequence of reduced Ca2+-release.
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Affiliation(s)
- Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA United States
| | - Steve Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA United States.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
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Jin JY, Guo BB, Dong Y, Sheng Y, Fan LL, Zhang LB. Case Report: A Novel CACNA1S Mutation Associated With Hypokalemic Periodic Paralysis in a Chinese Family. Front Genet 2021; 12:743184. [PMID: 34777470 PMCID: PMC8586648 DOI: 10.3389/fgene.2021.743184] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 10/12/2021] [Indexed: 11/13/2022] Open
Abstract
Hypokalemic periodic paralysis (HypoPP) is a rare autosomal dominant disorder characterized by episodic flaccid paralysis with concomitant hypokalemia. More than half of patients were associated with mutations in CACNA1S that encodes the alpha-1-subunit of the skeletal muscle L-type voltage-dependent calcium channel. Mutations in CACNA1S may alter the structure of CACNA1S and affect the functions of calcium channels, which damages Ca2+-mediated excitation-contraction coupling. In this research, we identified and described a Chinese HypoPP patient with a novel frameshift mutation in CACNA1S [NM_000069.2: c.1364delA (p.Asn455fs)] by targeted sequencing. This study would expand the spectrum of CACNA1S mutations, further our understanding of HypoPP, and provided a new perspective for selecting effective treatments.
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Affiliation(s)
- Jie-Yuan Jin
- School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, China
| | - Bing-Bing Guo
- School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, China.,CAS Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi Dong
- School of Life Sciences, Central South University, Changsha, China
| | - Yue Sheng
- School of Life Sciences, Central South University, Changsha, China
| | - Liang-Liang Fan
- School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, China.,Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Li-Bing Zhang
- Department of Pediatrics, Affiliated Hospital of Yangzhou University, Yangzhou, China
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Wu F, Quinonez M, Cannon SC. Gating pore currents occur in CaV1.1 domain III mutants associated with HypoPP. J Gen Physiol 2021; 153:212609. [PMID: 34463712 PMCID: PMC8563280 DOI: 10.1085/jgp.202112946] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/12/2021] [Indexed: 11/20/2022] Open
Abstract
Mutations in the voltage sensor domain (VSD) of CaV1.1, the α1S subunit of the L-type calcium channel in skeletal muscle, are an established cause of hypokalemic periodic paralysis (HypoPP). Of the 10 reported mutations, 9 are missense substitutions of outer arginine residues (R1 or R2) in the S4 transmembrane segments of the homologous domain II, III (DIII), or IV. The prevailing view is that R/X mutations create an anomalous ion conduction pathway in the VSD, and this so-called gating pore current is the basis for paradoxical depolarization of the resting potential and weakness in low potassium for HypoPP fibers. Gating pore currents have been observed for four of the five CaV1.1 HypoPP mutant channels studied to date, the one exception being the charge-conserving R897K in R1 of DIII. We tested whether gating pore currents are detectable for the other three HypoPP CaV1.1 mutations in DIII. For the less conserved R1 mutation, R897S, gating pore currents with exceptionally large amplitude were observed, correlating with the severe clinical phenotype of these patients. At the R2 residue, gating pore currents were detected for R900G but not R900S. These findings show that gating pore currents may occur with missense mutations at R1 or R2 in S4 of DIII and that the magnitude of this anomalous inward current is mutation specific.
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Affiliation(s)
- Fenfen Wu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
| | - Marbella Quinonez
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA
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Nicole S, Lory P. New Challenges Resulting From the Loss of Function of Na v1.4 in Neuromuscular Diseases. Front Pharmacol 2021; 12:751095. [PMID: 34671263 PMCID: PMC8521073 DOI: 10.3389/fphar.2021.751095] [Citation(s) in RCA: 1] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
The voltage-gated sodium channel Nav1.4 is a major actor in the excitability of skeletal myofibers, driving the muscle force in response to nerve stimulation. Supporting further this key role, mutations in SCN4A, the gene encoding the pore-forming α subunit of Nav1.4, are responsible for a clinical spectrum of human diseases ranging from muscle stiffness (sodium channel myotonia, SCM) to muscle weakness. For years, only dominantly-inherited diseases resulting from Nav1.4 gain of function (GoF) were known, i.e., non-dystrophic myotonia (delayed muscle relaxation due to myofiber hyperexcitability), paramyotonia congenita and hyperkalemic or hypokalemic periodic paralyses (episodic flaccid muscle weakness due to transient myofiber hypoexcitability). These last 5 years, SCN4A mutations inducing Nav1.4 loss of function (LoF) were identified as the cause of dominantly and recessively-inherited disorders with muscle weakness: periodic paralyses with hypokalemic attacks, congenital myasthenic syndromes and congenital myopathies. We propose to name this clinical spectrum sodium channel weakness (SCW) as the mirror of SCM. Nav1.4 LoF as a cause of permanent muscle weakness was quite unexpected as the Na+ current density in the sarcolemma is large, securing the ability to generate and propagate muscle action potentials. The properties of SCN4A LoF mutations are well documented at the channel level in cellular electrophysiological studies However, much less is known about the functional consequences of Nav1.4 LoF in skeletal myofibers with no available pertinent cell or animal models. Regarding the therapeutic issues for Nav1.4 channelopathies, former efforts were aimed at developing subtype-selective Nav channel antagonists to block myofiber hyperexcitability. Non-selective, Nav channel blockers are clinically efficient in SCM and paramyotonia congenita, whereas patient education and carbonic anhydrase inhibitors are helpful to prevent attacks in periodic paralyses. Developing therapeutic tools able to counteract Nav1.4 LoF in skeletal muscles is then a new challenge in the field of Nav channelopathies. Here, we review the current knowledge regarding Nav1.4 LoF and discuss the possible therapeutic strategies to be developed in order to improve muscle force in SCW.
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Affiliation(s)
- Sophie Nicole
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics (ICST), Montpellier, France
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Striessnig J. Voltage-Gated Ca 2+-Channel α1-Subunit de novo Missense Mutations: Gain or Loss of Function - Implications for Potential Therapies. Front Synaptic Neurosci 2021; 13:634760. [PMID: 33746731 PMCID: PMC7966529 DOI: 10.3389/fnsyn.2021.634760] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [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: 11/28/2020] [Accepted: 02/02/2021] [Indexed: 12/12/2022] Open
Abstract
This review summarizes our current knowledge of human disease-relevant genetic variants within the family of voltage gated Ca2+ channels. Ca2+ channelopathies cover a wide spectrum of diseases including epilepsies, autism spectrum disorders, intellectual disabilities, developmental delay, cerebellar ataxias and degeneration, severe cardiac arrhythmias, sudden cardiac death, eye disease and endocrine disorders such as congential hyperinsulinism and hyperaldosteronism. A special focus will be on the rapidly increasing number of de novo missense mutations identified in the pore-forming α1-subunits with next generation sequencing studies of well-defined patient cohorts. In contrast to likely gene disrupting mutations these can not only cause a channel loss-of-function but can also induce typical functional changes permitting enhanced channel activity and Ca2+ signaling. Such gain-of-function mutations could represent therapeutic targets for mutation-specific therapy of Ca2+-channelopathies with existing or novel Ca2+-channel inhibitors. Moreover, many pathogenic mutations affect positive charges in the voltage sensors with the potential to form gating-pore currents through voltage sensors. If confirmed in functional studies, specific blockers of gating-pore currents could also be of therapeutic interest.
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Affiliation(s)
- Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria
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