FIG 10.

H-Ras effector usage is affected by alterations in the acylation/deacylation balance. (A) Effects of the overexpression of ATs and PATs (1 μg) on the activation of cPLA₂ by H-Ras. ³H-labeled arachidonic acid release was measured in wild-type MEFs (MEFs +/+) or H-Ras knockout MEFs (MEFs −/−). Bars show the average ± SEM from three independent experiments. *, P < 0.05 with 95% confidence intervals. (B) Effects on H-Ras-mediated activation of RSK-1. RSK-1 phosphorylation levels relative to those in control cells are shown. C, control. (C) Time course of RSK-1 activation in HeLa and MCF-7 cells stimulated with EGF (100 ng/ml) for the indicated times. Where shown, H-Ras acylation/deacylation was altered by overexpression or downregulation (with siRNA) of the indicated proteins or by treatment with palmostatin B (1 μM, 80 min).