Figure 4.
RGS4 mutants show diminished GAP activity. The amount of GTP hydrolyzed per minute by Giα1 in the presence of wild-type RGS4 was determined as outlined in Materials and Methods. The GAP activity of each mutant protein is represented as a percentage of the amount of GTP hydrolyzed by Giα1 in the presence of wild-type RGS4 (100%). Data represent the average of 2–3 independent experiments.