The physical mechanism of calcium pump regulation in the heart

J. Voss, L. R. Jones, David D Thomas

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


The Ca-ATPase in the cardiac sarcoplasmic reticulum membrane is regulated by an amphipathic transmembrane protein, phospholamban. We have used time-resolved phosphorescence anisotropy to detect the microsecond rotational dynamics, and thereby the self-association, of the Ca-ATPase as a function of phospholamban phosphorylation and physiologically relevant calcium levels. The phosphorylation of phospholamban increases the rotational mobility of the Ca-ATPase in the sarcoplasmic reticulum bilayer, due to a decrease in large-scale protein association, with a [Ca2+] dependence parallel to that of enzyme activation. These results support a model in which phospholamban phosphorylation or calcium free the enzyme from a kinetically unfavorable associated state.

Original languageEnglish (US)
Pages (from-to)190-196
Number of pages7
JournalBiophysical journal
Issue number1
StatePublished - 1994

Bibliographical note

Funding Information:
We thank Nicoleta Cornea, Robert L. H. Bennett, and Franz L. Nisswandt for technical assistance. This work was supported by a grant to D.D.T. from the American Heart Association, Minnesota Affiliate.


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