Angiotensin II activates pp60c-src in vascular smooth muscle cells

Mari Ishida, Mario B. Marrero, Bernhard Schieffer, Takafumi Ishida, Kenneth E. Bernstein, Bradford C. Berk

Research output: Contribution to journalArticle

165 Scopus citations

Abstract

The angiotensin II type-1 (AT1) receptor, a G protein-coupled receptor, lacks intrinsic kinase activity. However, recent data show that angiotensin II (Ang II) stimulates tyrosine phosphorylation of phospholipase C-γ1 (PLC-γ1), Stat91 (one of the signal transducers and activators of transcription), and paxillin in vascular smooth muscle cells. The tyrosine kinases responsible for these phosphorylation events are unknown. Src family kinases have been shown to phosphorylate PLC-γ1 and to be activated by G protein-coupled receptors. We hypothesized that pp60c-src associates with the AT1 receptor and is activated after Ang II stimulation of smooth muscle cells. We immunoprecipitated pp60c-src from Ang II-stimulated vascular smooth muscle cells and measured pp60c-src activity by autophosphorylation and by phosphorylation of enolase. Both assays demonstrated an approximately threefold increase in pp60c-src activity within 1 minute. A similar increase in Ang II-stimulated pp60c-src activity was observed in Chinese hamster ovary cells transfected with the AT1 receptor but not in untransfected cells. These data are the first to show that pp60c-src is activated by Ang II. To determine if pp60s-src associated with the AT1 receptor, the AT1 receptor was immunoprecipitated (with two different antibodies), and Western blots were performed with two different anti-pp60c-src antibodies. No pp60c-src was detected. In addition, direct interaction between the AT1 receptor and pp60c-src could not be demonstrated by using a glutathione S-transferase (GST)-AT1 fusion protein to bind proteins from cell lysates stimulated by Ang II. In combination with recent findings that anti-pp60c-src antibodies inhibit Ang II-mediated PLC-γ1 phosphorylation, our data suggest an important role for pp60c-src in Ang II signal transduction.

Original languageEnglish (US)
Pages (from-to)1053-1059
Number of pages7
JournalCirculation research
Volume77
Issue number6
DOIs
StatePublished - Dec 1995

Keywords

  • Angiotensin II
  • Signal transduction
  • Src kinase
  • Vascular smooth muscle

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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    Ishida, M., Marrero, M. B., Schieffer, B., Ishida, T., Bernstein, K. E., & Berk, B. C. (1995). Angiotensin II activates pp60c-src in vascular smooth muscle cells. Circulation research, 77(6), 1053-1059. https://doi.org/10.1161/01.RES.77.6.1053