The first to be identified was Sst2 ("SuperSensiTivity to pheromone") in yeast (Saccharomyces cerevisiae).

[4] RGS domains in the G protein-coupled receptor kinases are able to bind to Gq family α-subunits, but do not accelerate their GTP hydrolysis.

Instead, GRKs appear to reduce Gq signaling by sequestering the active α-subunits away from effectors such as phospholipase C-β.

[5] Plants have RGS proteins but do not have canonical G protein-coupled receptors.

RGS domains can be found within the same protein in combination with a variety of other domains, including: DEP for membrane targeting (InterPro: IPR000591), PDZ for binding to GPCRs (InterPro: IPR001478), PTB for phosphotyrosine-binding (InterPro: IPR006020), RBD for Ras-binding (InterPro: IPR003116), GoLoco for guanine nucleotide inhibitor activity (InterPro: IPR003109), PX for phosphoinositide-binding (InterPro: IPR001683), PXA that is associated with PX (InterPro: IPR003114), PH for phosphatidylinositol-binding (InterPro: IPR001849), and GGL (G protein gamma subunit-like) for binding G protein beta subunits (InterPro: IPR001770 Those RGS proteins that contain GGL domains can interact with G protein beta subunits to form novel dimers that prevent G protein gamma subunit binding and G protein alpha subunit association, thereby preventing heterotrimer formation.