8dve
From Proteopedia
RyR1 in presence of IpCa-T26E phosphomimetic and activating ligands
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 PubMedCalcins are peptides from scorpion venom with the unique ability to cross cell membranes, gaining access to intracellular targets. Ryanodine Receptors (RyR) are intracellular ion channels that control release of Ca(2+) from the endoplasmic and sarcoplasmic reticulum. Calcins target RyRs and induce long-lived subconductance states, whereby single-channel currents are decreased. We used cryo-electron microscopy to reveal the binding and structural effects of imperacalcin, showing that it opens the channel pore and causes large asymmetry throughout the cytosolic assembly of the tetrameric RyR. This also creates multiple extended ion conduction pathways beyond the transmembrane region, resulting in subconductance. Phosphorylation of imperacalcin by protein kinase A prevents its binding to RyR through direct steric hindrance, showing how posttranslational modifications made by the host organism can determine the fate of a natural toxin. The structure provides a direct template for developing calcin analogs that result in full channel block, with potential to treat RyR-related disorders. Cryo-EM analysis of scorpion toxin binding to Ryanodine Receptors reveals subconductance that is abolished by PKA phosphorylation.,Haji-Ghassemi O, Chen YS, Woll K, Gurrola GB, Valdivia CR, Cai W, Li S, Valdivia HH, Van Petegem F Sci Adv. 2023 May 24;9(21):eadf4936. doi: 10.1126/sciadv.adf4936. Epub 2023 May , 24. PMID:37224245[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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