Figure 5.

The RGS domains of RGS4, RGS10 and GAIP stimulate hydrolysis of GTP bound to G_iα1 and G_zα. (A) Time curves of GTP hydrolysis for G_iα1 (500 nM) was preloaded with [γ-³²P]GTP at 30°C (estimated concentration of GTP–G_iα1 was 215 nM), then incubated at 0°C with R10 (50 nM) or RGAIP (1 μM). (B) Time curves of GTP hydrolysis for G_zα (2.5 nM) at 15°C and 50 nM of RGS4 and each RGS domain from RGS4 (R4), GAIP (RGAIP), and RGS10 (R10).