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Regulator of G protein signaling (RGS) domain found in the RGS17 protein The RGS (Regulator of G-protein Signaling) domain is an essential part of the RGS17 protein, a member of the RZ subfamily of the RGS protein family. They are a diverse group of multifunctional proteins that regulate cellular signaling events downstream of G-protein coupled receptors (GPCRs). As a major G-protein regulator, the 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 play critical regulatory roles as GTPase activating proteins (GAPs) of the heterotrimeric G-protein G-alpha-subunits. Deactivation of the G-protein signaling controlled by the RGS domain, which accelerates GTPase activity of the alpha subunit by hydrolysis of GTP to GDP, results in reassociation of the alpha-subunit with the beta-gamma-dimer and inhibition of downstream activity. The RZ subfamily of RGS proteins includes RGS19 (former GAIP), RGS20, and its splice variant Ret-RGS. RGS17 is a relatively non-selective GAP for G-alpha-z and other G-alpha-i/o proteins. RGS17 blocks dopamine receptor-mediated inhibition of cAMP accumulation; it also blocks thyrotropin releasing hormone-stimulated Ca++ mobilization. RGS17, like other members of RZ subfamily, can act either as a GAP or as G-protein effector antogonist.
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