Fig. 7.

Mutation of IRS-1 does not prevent its degradation by ANG II. VSMCs were transfected with IRS-1 mutants S632A (A), S307A (B), and S302A (C), as described in materials and methods, and incubated with ANG II (100 nM) for 18 h. Western blotting with antibodies against total IRS-1, hemagglutinin (HA)-tag, or β-tubulin was performed. There was no significant difference in IRS-1 levels between wild type (WT) and mutants in the presence of ANG II (bar 4 vs. 6 in A, B, and C). Bar graphs represent means ± SE (in A and B, n = 4; in C, n = 3). *P < 0.05 compared with no stimulation for the corresponding transfection.