Role of intracellular calcium in the angiotensin II-mediated tyrosine phosphorylation and dephosphorylation of PLC-γl

J. B. Harp, P. P. Sayeski, M. Scanlon, K. E. Bernstein, M. B. Marrero

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Angiotensin II induces the rapid temporal tyrosine phosphorylation and activation of phospholipase C-γ1 (PLC-γl) and the elevation of intracellular calcium levels. To investigate the relationship of these intracellular signaling events, rat aortic smooth muscle cells were treated with the calcium chelator BAPTA-AM, the calcium channel blocker verapamil, the intracellular calcium antagonist TMB-8, and the calcium ionophore ionomycin. The effects of these agents on PLC-γl tyrosine phosphorylation were then measured. We found that treatment of these cells with the calcium inhibitors augmented the basal level of PLC-γl tyrosine phosphorylation, without changing the peak level of tyrosine phosphorylation induced by angiotensin II. The rapid dephosphorylation of PLC-γ1 that follows angiotensin II stimulation was prevented by these calcium antagonists. In contrast, angiotensin II-induced tyrosine phosphorylation of PLC-γl was inhibited by ionomycin. These results suggest that the angiotensin II-induced tyrosine phosphorylation of PLC-γ1 is calcium-independent, while the dephosphorylation is calcium-dependent.

Original languageEnglish (US)
Pages (from-to)540-544
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume232
Issue number2
DOIs
StatePublished - Mar 17 1997

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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