Roles of Tyr122-hydrophobic cluster and K+ binding in Ca2+ -releasing process of ADP-insensitive phosphoenzyme of sarcoplasmic reticulum Ca2+ -ATPase.

The Journal of Biological Chemistry
Kazuo YamasakiHiroshi Suzuki

Abstract

Tyr(122)-hydrophobic cluster (Y122-HC) is an interaction network formed by the top part of the second transmembrane helix and the cytoplasmic actuator and phosphorylation domains of sarcoplasmic reticulum Ca(2+)-ATPase. We have previously found that Y122-HC plays critical roles in the processing of ADP-insensitive phosphoenzyme (E2P) after its formation by the isomerization from ADP-sensitive phosphoenzyme (E1PCa(2)) (Wang, G., Yamasaki, K., Daiho, T., and Suzuki, H. (2005) J. Biol. Chem. 280, 26508-26516). Here, we further explored kinetic properties of the alanine-substitution mutants of Y122-HC to examine roles of Y122-HC for Ca(2+) release process in E2P. In the steady state, the amount of E2P decreased so that of E1PCa(2) increased with increasing lumenal Ca(2+) concentration in the mutants with K(0.5) 110-320 microm at pH 7.3. These lumenal Ca(2+) affinities in E2P agreed with those estimated from the forward and lumenal Ca(2+)-induced reverse kinetics of the E1PCa(2)-E2P isomerization. K(0.5) of the wild type in the kinetics was estimated to be 1.5 mM. Thus, E2P of the mutants possesses significantly higher affinities for lumenal Ca(2+) than that of the wild type. The kinetics further indicated that the rates of lumenal ...Continue Reading

References

Jul 1, 1990·Physiological Reviews·G InesiM E Kirtley
May 1, 1988·Proceedings of the National Academy of Sciences of the United States of America·K Maruyama, D H MacLennan
May 6, 1996·Biochimica Et Biophysica Acta·J V MøllerM le Maire
Feb 1, 1996·Journal of Molecular Graphics·W HumphreyK Schulten
Nov 20, 1997·The Journal of Biological Chemistry·D H MacLennanN M Green
Aug 9, 2002·Nature·Chikashi Toyoshima, Hiromi Nomura
Nov 25, 2003·FEBS Letters·Chikashi ToyoshimaYuji Sugita
Jun 11, 2004·Annual Review of Biochemistry·Chikashi Toyoshima, Giuseppe Inesi
Jun 12, 2004·Science·Thomas Lykke-Møller SørensenPoul Nissen
Jul 2, 2004·Nature·Chikashi Toyoshima, Tatsuaki Mizutani
Sep 24, 2004·The Journal of Biological Chemistry·Thomas Lykke-Møller SørensenPoul Nissen
Dec 25, 2004·Science·Claus OlesenPoul Nissen
Mar 29, 2007·Proceedings of the National Academy of Sciences of the United States of America·Mihoko TakahashiChikashi Toyoshima
Dec 14, 2007·Nature·Claus OlesenPoul Nissen
Dec 14, 2007·Proceedings of the National Academy of Sciences of the United States of America·Chikashi ToyoshimaHaruo Ogawa
May 6, 2008·Archives of Biochemistry and Biophysics·Chikashi Toyoshima

❮ Previous
Next ❯

Citations

Sep 3, 2010·Quarterly Reviews of Biophysics·Jesper V MøllerPoul Nissen
Oct 13, 2010·The Journal of Biological Chemistry·Kazuo YamasakiHiroshi Suzuki
Feb 2, 2010·Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan·Hiroshi SuzukiStefania Danko
Jul 17, 2010·Current Opinion in Structural Biology·Maike BublitzPoul Nissen
Nov 7, 2009·The EMBO Journal·Megan J MaherKen Yokoyama
Sep 24, 2014·The Journal of Biological Chemistry·Takashi DaihoHiroshi Suzuki
Jun 6, 2013·The Journal of Biological Chemistry·Kazuo YamasakiHiroshi Suzuki
Feb 27, 2019·Journal of Chemical Theory and Computation·Bin SunPeter M Kekenes-Huskey
Oct 2, 2021·Proceedings of the National Academy of Sciences of the United States of America·Chigusa KobayashiYuji Sugita

❮ Previous
Next ❯

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.