Fig. 2.

Classical RGS subfamily and related structural domains. Based on the RGS homology and structural domains, the classical RGS proteins were divided into four subfamilies. The four subfamilies are RGS A/RZ, B/R4, C/R7 and D/R12, and the members of each subfamily are also listed in the figure. Each subfamily contains a G protein-specific RGS domain (RH), the "RGS Box", which acts on the Gα subunit and exhibits GAP activity, in addition to the cysteine string (CYS) in the RGS A/RZ subfamily. R4 subfamily RGS3 also has the domains of PSD-95, Dlg, and ZO-1/2 (PDZ); the R7 subfamily also contains the Dishevelled/EGL10/pleckstrin domain (DEP) and G-protein γ-like domain (GGL); and the R12 subfamily contains the phosphotyrosine-binding domain (PTB), Raf-like Ras-binding domain (RBD) and G-protein regulatory motif (GoLoco) in addition to the PDZ structural domain