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Updated: Jul 31, 2026

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling
Published on: August 1, 2016
Structural basis of ion pumping by Ca(2+)-ATPase of sarcoplasmic reticulum
Chikashi Toyoshima1, Hiromi Nomura, Yuji Sugita
1Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan. ct@iam.u-tokyo.ac.jp
Abstract:
The structures of the Ca(2+)-ATPase (SERCA1a) have been determined for five different states by X-ray crystallography. Detailed comparison of the structures in the Ca(2+)-bound form and unbound (but thapsigargin-bound) form reveals that very large rearrangements of the transmembrane helices take place accompanying Ca2+ dissociation and binding and that they are mechanically linked with equally large movements of the cytoplasmic domains. The meanings of the rearrangements of the transmembrane helices and those of the cytoplasmic domains, and the mechanistic roles of the phosphorylation are now becoming clear.
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