Figure 4.

Phosphorylation of RhoA at Ser188 by elevated intracellular cAMP. Serum-starved cells were pretreated with Fsk + rolipram for 30 minutes followed by ET-1 for 10 minutes. (A) Fsk increased the phosphorylation of RhoA at Ser188 in a time-dependent manner, with a maximum increase occurring at 10 minutes, and remained constant until after 20 minutes. The increase in Ser188 phosphorylation by Fsk (217% compared with control 100%) was significant (P = 0.005) and unaffected by further treatment with ET-1 (B). (C) Bar graph of data from at least three independent experiments, similar to that in (B). Results are represented as mean ± SEM. ET-1, endothelin-1; Fsk, forskolin.