Key Points
- To determine the effects of angiotensin II on the phosphorylation of the vascular type 1 angiotensin II receptor in rat aortic vascular smooth muscle cells.
- Treated rat aortic vascular smooth muscle cells labeled with [32P]orthophosphate with angiotensin II, forskolin, phorbol 12-myristate-13-acetate, and ionomycin.
- Conducted immunoprecipitation using anti-AT1AR and anti-phosphotyrosine antibodies, followed by phosphoamino acid analysis to assess serine, threonine, and tyrosine phosphorylation.
- Angiotensin II induced rapid, dose-dependent phosphorylation of the 52-kD AT1A receptor peaking at 20 minutes, primarily occurring at serine residues with lower levels of constitutive and stimulated tyrosine phosphorylation.
- Forskolin increased total AT1AR phosphorylation without altering tyrosine phosphorylation, whereas phorbol 12-myristate-13-acetate and ionomycin caused no detectable changes in receptor phosphorylation.
Structured PICO
PPopulationRat aortic vascular smooth muscle cells
IInterventionAngiotensin II (Ang II)
CComparatorBasal state / untreated cells
OOutcomePhosphorylation of the vascular type 1 angiotensin II receptor (AT1AR)surrogate
Angiotensin II induces phosphorylation of its own G protein-coupled receptor (AT1AR) via serine and tyrosine kinases, suggesting a mechanism for regulating receptor function.