Hormone-induced phosphorylation of the plasma membrane calcium pump in cultured aortic endothelial cells

Kevin K.W. Wang, Yeng Sheng Du, Clement Diglio, Wayne Tsang, Tuan H. Kuo

Research output: Contribution to journalArticle

27 Scopus citations


The regulation of the plasma membrane Ca2+ pump by hormones via phosphorylation in intact cells has not been clearly established. We now present evidence that the Ca2+ pump is phosphorylated on both serine and threonine residues in unstimulated and stimulated cultured rat aortic endothelial cells. Among the stimuli tested, the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) was most potent and increased the level of phosphorylation threefold, while the cAMP-dependent protein kinase activator 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) stimulated the phosphorylation 1.6-fold. Two-dimensional tryptic phosphopeptide maps of the Ca2+ pump from unstimulated and CPT-cAMP-stimulated cells have identical patterns (five phosphopeptides) while PMA-stimulated cells have three additional phosphopeptides. Isoproterenol-, ATP-, angiotensin II-, and bradykinin-stimulated cells also have increased levels of Ca2+ pump phosphorylation. Stimuli-induced phosphorylation of the Ca2+ pump was rapid (5-10 min) and was concomitant with stimulated calcium efflux from the same cells. This is the first direct evidence that the plasma membrane Ca2+ pump in intact cells is regulated by various hormones or agonists via cAMP-dependent protein kinase or protein kinase C phosphorylation.

Original languageEnglish (US)
Pages (from-to)103-108
Number of pages6
JournalArchives of Biochemistry and Biophysics
Issue number1
StatePublished - Aug 15 1991
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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