6jrr

Publication Abstract from PubMed

The high-conductance intracellular calcium (Ca(2+)) channel RyR2 is essential for the coupling of excitation and contraction in cardiac muscle. Among various modulators, calmodulin (CaM) regulates RyR2 in a Ca(2+)-dependent manner. Here we reveal the regulatory mechanism by which porcine RyR2 is modulated by human CaM through the structural determination of RyR2 under eight conditions. Apo-CaM and Ca(2+)-CaM bind to distinct but overlapping sites in an elongated cleft formed by the handle, helical and central domains. The shift in CaM-binding sites on RyR2 is controlled by Ca(2+) binding to CaM, rather than to RyR2. Ca(2+)-CaM induces rotations and intradomain shifts of individual central domains, resulting in pore closure of the PCB95 and Ca(2+)-activated channel. By contrast, the pore of the ATP, caffeine and Ca(2+)-activated channel remains open in the presence of Ca(2+)-CaM, which suggests that Ca(2+)-CaM is one of the many competing modulators of RyR2 gating.

Modulation of cardiac ryanodine receptor 2 by calmodulin.,Gong D, Chi X, Wei J, Zhou G, Huang G, Zhang L, Wang R, Lei J, Chen SRW, Yan N Nature. 2019 Jul 5. pii: 10.1038/s41586-019-1377-y. doi:, 10.1038/s41586-019-1377-y. PMID:31278385^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.