Ca2+-transporting ATPase, phospholamban, and calsequestrin levels in nonfailing and failing human myocardium

M. A. Movsesian, M. Karimi, K. Green, L. R. Jones

Research output: Contribution to journalArticle

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Abstract

Background: Observations of abnormalities in the diastolic components of intracellular Ca2+ transients in failing human left ventricular myocardium have raised the possibility that reductions in the level or function of sarcoplasmic reticulum proteins involved in Ca2+ transport contribute to the pathophysiology of dilated cardiomyopathy in humans. Functional assays, however, have revealed no differences in ATP-dependent Ca2+ transport or its modulation by phospholamban in sarcoplasmic reticulum-enriched microsomes prepared from nonfailing and failing human left ventricular myocardium. The purpose of the present study was to quantify protein levels of Ca2+-transporting ATPase, phospholamban, and calsequestrin directly in nonfailing and failing human left ventricular myocardium. Methods and Results: Total protein extracts were prepared from nonfailing left ventricular myocardium from the hearts of unmatched organ donors with normal left ventricular contractility (n=6) and from failing left ventricular myocardium from the excised hearts of transplant recipients with class IV heart failure resulting from idiopathic dilated cardiomyopathy (n=6). Ca2+-transporting ATPase, phospholamban, and calsequestrin contents were determined by quantitative immunoblotting with monoclonal and affinity-purified polyclonal antibodies. The levels of the three proteins were identical in nonfailing and failing human left ventricular myocardium. Conclusions: These results indicate that protein levels of Ca2+-transporting ATPase, phospholamban, and calsequestrin are not diminished in failing human left ventricular myocardium and that downregulation of the Ca2+-transporting ATPase and phospholamban is not part of the molecular pathophysiology of dilated cardiomyopathy in humans.

Original languageEnglish (US)
Pages (from-to)653-657
Number of pages5
JournalCirculation
Volume90
Issue number2
DOIs
StatePublished - Jan 1 1994

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Keywords

  • Ca ATPase
  • Calsequestrin
  • Cardiomyopathy
  • Phospholamban

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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