Angiotensin II AT1 receptor signal transduction has recently been shown to function through the phospholipase C isozyme, PLC-γ. Since PLC-γ is known to interact with phosphotyrosine containing proteins through SH2 domains, we examined the phosphorylation state of the AT1 receptor. Immunoprecipitation of the [32P] labeled AT1 receptor from rat aortic smooth muscle cells followed by alkali hydrolysis demonstrated the presence of tyrosine phosphorylation. Phosphoamino acid analysis of the excised bands demonstrated the presence of phosphoserine and phosphotyrosine residues. A fusion protein comprising the intracellular tail of the AT1 receptor was used to screen for candidate kinases, and the src kinase family displayed high activity. In summary, this study shows that the AT1 receptor is serine and tyrosine phosphorylated in vivo and suggests that a soluble kinase related to the src family may be responsible for the tyrosine phosphorylation.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Apr 15 1994|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology