Regulates G protein-coupled receptor signaling cascades, including signaling downstream of the muscarinic acetylcholine receptor CHRM2. Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits, thereby driving them into their inactive GDP-bound form (PubMed:8774883, PubMed:10608901, PubMed:9353196, PubMed:11443111, PubMed:18434541). Modulates the activity of potassium channels that are activated in response to CHRM2 signaling (PubMed:11443111). Activity on GNAZ is inhibited by palmitoylation of the G-protein (PubMed:9353196). Interacts with GNAZ, GNAI1 and GNAI3 (PubMed:8774883, PubMed:11443111, PubMed:18434541). Associates specifically with the activated, GTP-bound forms of GNAZ and GNAI3 (PubMed:8774883). Forskolin treatment promotes phosphorylation and translocation to the nucleus.