Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1S gives rise to L-type calcium currents. Long-lasting (L-type) calcium channels belong to the 'high-voltage activated' (HVA) group. They are blocked by dihydropyridines (DHP), phenylalkylamines, benzothiazepines, and by omega-agatoxin-IIIA (omega-Aga-IIIA). They are however insensitive to omega-conotoxin-GVIA (omega-CTx-GVIA) and omega-agatoxin-IVA (omega-Aga-IVA). Calcium channels containing the alpha-1S subunit play an important role in excitation-contraction coupling in skeletal muscle.
Catalysis of the transmembrane transfer of a calcium ion by a high voltage-gated channel. A high voltage-gated channel is a channel whose open state is dependent on high voltage across the membrane in which it is embedded.
J. Neurosci. 18, 10320-10334 (1998)[PubMed:9852570]
The skeletal muscle L-type Ca channel serves a dual role as a calcium-conducting pore and as the voltage sensor coupling t-tubule depolarization to calcium release from the sarcoplasmic reticulum. Mutations in this channel cause hypokalemic periodic paralysis (HypoPP), a human autosomal dominant disorder characterized by episodic failure of muscle excitability that occurs in association with a decrease in serum potassium. The voltage-dependent gating of L-type Ca channels was characterized by recording whole-cell Ca currents in myotubes cultured from three normal individuals and from a patient carrying the HypoPP mutation R528H. We found two effects of the R528H mutation on the L-type Ca current in HypoPP myotubes: (1) a mild reduction in current density and (2) a significant slowing of the rate of activation. We also measured the voltage dependence of steady-state L-type Ca current inactivation and characterized, for the first time in a mammalian preparation, the kinetics of both entry into and recovery from inactivation over a wide range of voltages. The R528H mutation had no effect on the kinetics or voltage dependence of inactivation.
Catalysis of the transmembrane transfer of a calcium ion by a voltage-gated channel. A voltage-gated channel is a channel whose open state is dependent on the voltage across the membrane in which it is embedded.
J. Neurosci. 18, 10320-10334 (1998)[PubMed:9852570]
The skeletal muscle L-type Ca channel serves a dual role as a calcium-conducting pore and as the voltage sensor coupling t-tubule depolarization to calcium release from the sarcoplasmic reticulum. Mutations in this channel cause hypokalemic periodic paralysis (HypoPP), a human autosomal dominant disorder characterized by episodic failure of muscle excitability that occurs in association with a decrease in serum potassium. The voltage-dependent gating of L-type Ca channels was characterized by recording whole-cell Ca currents in myotubes cultured from three normal individuals and from a patient carrying the HypoPP mutation R528H. We found two effects of the R528H mutation on the L-type Ca current in HypoPP myotubes: (1) a mild reduction in current density and (2) a significant slowing of the rate of activation. We also measured the voltage dependence of steady-state L-type Ca current inactivation and characterized, for the first time in a mammalian preparation, the kinetics of both entry into and recovery from inactivation over a wide range of voltages. The R528H mutation had no effect on the kinetics or voltage dependence of inactivation.
J. Neurosci. 18, 10320-10334 (1998)[PubMed:9852570]
The skeletal muscle L-type Ca channel serves a dual role as a calcium-conducting pore and as the voltage sensor coupling t-tubule depolarization to calcium release from the sarcoplasmic reticulum. Mutations in this channel cause hypokalemic periodic paralysis (HypoPP), a human autosomal dominant disorder characterized by episodic failure of muscle excitability that occurs in association with a decrease in serum potassium. The voltage-dependent gating of L-type Ca channels was characterized by recording whole-cell Ca currents in myotubes cultured from three normal individuals and from a patient carrying the HypoPP mutation R528H. We found two effects of the R528H mutation on the L-type Ca current in HypoPP myotubes: (1) a mild reduction in current density and (2) a significant slowing of the rate of activation. We also measured the voltage dependence of steady-state L-type Ca current inactivation and characterized, for the first time in a mammalian preparation, the kinetics of both entry into and recovery from inactivation over a wide range of voltages. The R528H mutation had no effect on the kinetics or voltage dependence of inactivation.
A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of the endoplasmic reticulum.
The process whose specific outcome is the progression of the extraocular skeletal muscle over time, from its formation to the mature structure. The extraocular muscle is derived from cranial mesoderm and controls eye movements. The muscle begins its development with the differentiation of the muscle cells and ends with the mature muscle. An example of this process is found in Mus musculus.
A process in which force is generated within muscle tissue, resulting in a change in muscle geometry. Force generation involves a chemo-mechanical energy conversion step that is carried out by the actin/myosin complex activity, which generates force through ATP hydrolysis.
Evidence
1:
Inferred from Mutant PhenotypeUniProtKB
Hypokalaemic periodic paralysis (HypoKPP) is a skeletal muscle channelopathy caused by mutations in calcium (CACNA1S) and sodium (SCN4A) channel subunits. A small number of causative mutations have been found in European and Asian patients, but not in African patients yet. We have identified a large Beninese family in which HypoKPP segregated over five generations and was caused by the CACNA1S R1239H mutation. We report on the clinical and histopathological spectrum of the disorder in this family. A later age at onset (15.8+/-8.8years), and particular triggering factors due to specific African life conditions seem to be characteristic of our observation.
A process in which non-proliferating myoblasts fuse to existing fibers or to myotubes to form new fibers. A myoblast is a mononucleate cell type that, by fusion with other myoblasts, gives rise to the myotubes that eventually develop into skeletal muscle fibers.
A process that is carried out at the cellular level which results in the assembly, arrangement of constituent parts, or disassembly of a neuromuscular junction.
The process whose specific outcome is the progression of the skeleton over time, from its formation to the mature structure. The skeleton is the bony framework of the body in vertebrates (endoskeleton) or the hard outer envelope of insects (exoskeleton or dermoskeleton).
A process in which force is generated within striated muscle tissue, resulting in the shortening of the muscle. Force generation involves a chemo-mechanical energy conversion step that is carried out by the actin/myosin complex activity, which generates force through ATP hydrolysis. Striated muscle is a type of muscle in which the repeating units (sarcomeres) of the contractile myofibrils are arranged in registry throughout the cell, resulting in transverse or oblique striations observable at the level of the light microscope.
IEAOrtholog Compara
Pathways
According to KEGG, this protein belongs to the following pathways:
Protein involved in the transport of calcium ions. Calcium is essential for a variety of bodily functions, such as neurotransmission, muscle contraction and proper heart function.
Protein involved in the transport of ions. Such proteins are usually transmembrane and mediate a movement of ions across cell membranes. Transport may be passive (facilitated diffusion; down the electrochemical gradient), or active (against the electrochemical gradient). Active transport requires energy which may come from light, oxidation reactions, ATP hydrolysis, or cotransport of other ions or molecules.
Protein involved in the transport of a molecule (metabolite, protein, etc), a ion or an electron across cell membranes, inside the cell or in a tissue fluid.
Cell membrane glycoprotein forming a channel in a biological membrane selectively permeable to calcium ions. Calcium is essential for a variety of bodily functions, such as neurotransmission, muscle contraction and proper heart function.
Protein which is part of a transmembrane protein complex that forms a hydrophilic channel across the lipid bilayer through which specific inorganic ions can diffuse down their electrochemical gradients. The channels are usually gated and only open in response to a specific stimulus, such as a change in membrane potential (voltage-gated) or the binding of a ligand (ligand-gated channel).
Protein which is a component of a voltage-gated channel. Voltage-gated ion channels are responsible for the electrical activity in a variety of cell types. They probably exist in all life forms.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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