4i96
From Proteopedia
Crystal structure of the N-terminal two domains of the skeletal muscle ryanodine receptor (rabbit RyR1) residues 217-536
Structural highlights
Function[RYR1_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 PubMedRyanodine receptors are large channels that release Ca(2+) from the endoplasmic and sarcoplasmic reticulum. Hundreds of RyR mutations can cause cardiac and skeletal muscle disorders, yet detailed mechanisms explaining their effects have been lacking. Here we compare pseudo-atomic models and propose that channel opening coincides with widening of a cytoplasmic vestibule formed by the N-terminal region, thus altering an interface targeted by 20 disease mutations. We solve crystal structures of several disease mutants that affect intrasubunit domain-domain interfaces. Mutations affecting intrasubunit ionic pairs alter relative domain orientations, and thus couple to surrounding interfaces. Buried disease mutations cause structural changes that also connect to the intersubunit contact area. These results suggest that the intersubunit contact region between N-terminal domains is a prime target for disease mutations, direct or indirect, and we present a model whereby ryanodine receptors and inositol-1,4,5-trisphosphate receptors are activated by altering domain arrangements in the N-terminal region. Disease mutations in the ryanodine receptor N-terminal region couple to a mobile intersubunit interface.,Kimlicka L, Lau K, Tung CC, Van Petegem F Nat Commun. 2013;4:1506. doi: 10.1038/ncomms2501. PMID:23422674[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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