3jbr
From Proteopedia
Cryo-EM structure of the rabbit voltage-gated calcium channel Cav1.1 complex at 4.2 angstrom
Structural highlights
Function[CCG1_RABIT] This protein is a subunit of the dihydropyridine (DHP) sensitive calcium channel. Plays a role in excitation-contraction coupling. The skeletal muscle DHP-sensitive Ca(2+) channel may function only as a multiple subunit complex. [CACB2_RAT] The beta subunit of voltage-dependent calcium channels contributes to the function of the calcium channel by increasing peak calcium current, shifting the voltage dependencies of activation and inactivation, modulating G protein inhibition and controlling the alpha-1 subunit membrane targeting (By similarity).[1] [2] [3] [CAC1S_RABIT] 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. [CA2D1_RABIT] The alpha-2/delta subunit of voltage-dependent calcium channels regulates calcium current density and activation/inactivation kinetics of the calcium channel. Plays an important role in excitation-contraction coupling. Publication Abstract from PubMedThe voltage-gated calcium channel Ca(v)1.1 is engaged in the excitation-contraction coupling of skeletal muscles. The Ca(v)1.1 complex consists of the pore-forming subunit alpha1 and auxiliary subunits alpha2delta, beta, and gamma. We report the structure of the rabbit Ca(v)1.1 complex determined by single-particle cryo-electron microscopy. The four homologous repeats of the alpha1 subunit are arranged clockwise in the extracellular view. The gamma subunit, whose structure resembles claudins, interacts with the voltage-sensing domain of repeat IV (VSD(IV)), whereas the cytosolic beta subunit is located adjacent to VSD(II) of alpha1. The alpha2 subunit interacts with the extracellular loops of repeats I to III through its VWA and Cache1 domains. The structure reveals the architecture of a prototypical eukaryotic Ca(v) channel and provides a framework for understanding the function and disease mechanisms of Ca(v) and Na(v) channels. Structure of the voltage-gated calcium channel Cav1.1 complex.,Wu J, Yan Z, Li Z, Yan C, Lu S, Dong M, Yan N Science. 2015 Dec 18;350(6267):aad2395. doi: 10.1126/science.aad2395. PMID:26680202[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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