Regulates G protein-coupled receptor signaling cascades. Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits, thereby driving them into their inactive GDP-bound form (PubMed:11063746, PubMed:19478087). It is involved in the negative regulation of the angiotensin-activated signaling pathway (PubMed:28784619). Plays a role in the regulation of blood pressure in response to signaling via G protein-coupled receptors and GNAQ. Plays a role in regulating the constriction and relaxation of vascular smooth muscle (By similarity). Binds EIF2B5 and blocks its activity, thereby inhibiting the translation of mRNA into protein (PubMed:19736320). Interacts with GNAQ (PubMed:18434541, PubMed:19478087, PubMed:28784619). Does not interact with GNAI1 and GNAI3 (PubMed:18434541, PubMed:19478087). Interacts with EIF2B5 (PubMed:19736320). Interacts with PRKG1 (isoform alpha) (PubMed:14608379). Expressed in acute myelogenous leukemia (AML) and in acute lymphoblastic leukemia (ALL). Phosphorylated by protein kinase C. Phosphorylation by PRKG1 leads to activation of RGS2 activity. Lacks type V adenylyl cyclase (AC) inhibitory function. Lacks type V adenylyl cyclase (AC) inhibitory function.