Regulator of G protein signaling (RGS) domain found in the Axin protein
The RGS (Regulator of G-protein Signaling) domain is an essential part of the Axin protein. Axin is a member of the RA/RGS subfamily of the RGS protein family, a diverse group of multifunctional proteins that regulate cellular signaling events downstream of G-protein coupled receptors (GPCRs). As a major G-protein regulator, RGS domain containing proteins are involved in many crucial cellular processes such as regulation of intracellular trafficking, glial differentiation, embryonic axis formation, skeletal and muscle development, and cell migration during early embryogenesis. RGS proteins regulate many aspects of embryonic development such as glial differentiation, embryonic axis formation, and skeletal and muscle development. The RGS domain of Axin is specifically interacts with the heterotrimeric G-alpha12 protein, but not with closely related G-alpha13, and provides a unique tool to regulate G-alpha12-mediated signaling processes. The RGS domain of Axin also interacts with the tumor suppressor protein APC (Adenomatous Polyposis Coli) in order to control the cytoplasmic level of the proto-oncogene, beta-catenin.