RGS 3 (Regulator of G protein Signaling 3) is widely expressed in many tissues and cells. The protein contains an RGS domain near the carboxy terminus that serves as a GTPase activating protein (GAP). RGS 3 negatively regulates the activation of Gialpha and G alpha q. A truncated RGS 3 (RGS 3T), with its N-terminal 313 residues removed, has been shown to negatively regulate acenylyl cyclase and PLC. RGS 3T may be localized in the nucleus and RGS 3 is found in cytoplasm. Translocation to the membrane is important for the RGS proteins to interact with heterotrimeric G proteins.