Figure 4.

Functional activity of Gγ-like domain in RGS7. (A) Structural domains in wild-type RGS7 and its mutants. The thinner bar represents the length of the protein. The stippled box is the RGS core domain; the solid box denotes the Gγ-like domain. The open box is the “DEP,” which also is found in RGS6, 7, and 9 and EGL-10; its sequence is homologous to pleckstrin (29) but the function is unknown. In the RGS7Δ mutant, the Gγ-like domain is deleted, and in the RGS7γ1 mutant, it is replaced with a portion of Gγ1 (hatched box). (B) Interaction of the mutants with Gβ5 and Gβ1. The experiments were carried out by using the ³⁵S-labeled proteins and testing the Gβ5-RGS interaction using Sepharose S as described in the Fig. 2 legend. Gβ5 binds the wild-type RGS7 (Top), but not the RGS7Δ mutant (Middle). (Bottom) RGS7γ1 mutant binds Gβ1 instead of Gβ5.