Figure 4.

GAP Accelerates GTPase Activity of RAC5.

(A) RhoGAP1 accelerates GTPase activity of RAC5 in a dose-dependent manner. Approximately 100 or 500 ng of GST:RhoGAP1 protein was added to the reactions, and the amount of radioactivity retained on filters indicating the amount of GTP-bound RAC5 measured after the indicated time.

(B) RhoGAP1 accelerates GTPase activity of RAC5 and Hs RAC1. Approximately 0.5 μg of RhoGAP1 protein was used. Otherwise, experimental conditions were similar to those described in (A).

(C) Both full-length and the C-terminal domain containing the RhoGAP domain of RhoGAP1 accelerate RAC5 GTPase activity. Approximately 0.2 μg each of GST:RhoGAP1 and GST:RhoGAP1 C-terminal protein (amino acids 142 to end) were used to activate RAC5. Measurements were made as in (A).

Assays are representative examples of experiments repeated at least three times, with similar results.