Inhibits signal transduction by increasing the GTPase activity of G protein alpha subunits thereby driving them into their inactive GDP-bound form. Activity on G(z)-alpha is inhibited by phosphorylation of the G-protein. Activity on G(z)-alpha and G(i)-alpha-1 is inhibited by palmitoylation of the G-protein. May be produced by alternative promoter usage. Expressed in brain and heart. Expressed in brain at protein level. Expressed in prefontal and visual cortex. Isoform 4 and isoform 5 are expressed ubiquitously. Isoform 1, isoform 2 and isoform 3 are not expressed in the cerebellum. Palmitoylated on Cys-2 and/or Cys-12. Phosphorylated by cyclic GMP-dependent protein kinase. Disease susceptibility may be associated with variants affecting the gene represented in this entry.