4uwe
From Proteopedia
Structure of the ryanodine receptor at resolution of 8.5 A in partially open state
Structural highlights
FunctionRYR1_RABIT Calcium channel that mediates the release of Ca(2+) from the sarcoplasmic reticulum into the cytoplasm and thereby plays a key role in triggering muscle contraction following depolarization of T-tubules. Repeated very high-level exercise increases the open probability of the channel and leads to Ca(2+) leaking into the cytoplasm. Can also mediate the release of Ca(2+) from intracellular stores in neurons, and may thereby promote prolonged Ca(2+) signaling in the brain. Required for normal embryonic development of muscle fibers and skeletal muscle. Required for normal heart morphogenesis, skin development and ossification during embryogenesis (By similarity).[1] [2] Publication Abstract from PubMedMuscle contraction is initiated by the release of calcium (Ca2+) from the sarcoplasmic reticulum into the cytoplasm of myocytes through ryanodine receptors (RyRs). RyRs are homotetrameric channels with a molecular mass of more than 2.2 megadaltons that are regulated by several factors, including ions, small molecules and proteins. Numerous mutations in RyRs have been associated with human diseases. The molecular mechanism underlying the complex regulation of RyRs is poorly understood. Using electron cryomicroscopy, here we determine the architecture of rabbit RyR1 at a resolution of 6.1 A. We show that the cytoplasmic moiety of RyR1 contains two large alpha-solenoid domains and several smaller domains, with folds suggestive of participation in protein-protein interactions. The transmembrane domain represents a chimaera of voltage-gated sodium and pH-activated ion channels. We identify the calcium-binding EF-hand domain and show that it functions as a conformational switch allosterically gating the channel. Architecture and conformational switch mechanism of the ryanodine receptor.,Efremov RG, Leitner A, Aebersold R, Raunser S Nature. 2014 Dec 1. doi: 10.1038/nature13916. PMID:25470059[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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