RGS9-2 is of particular interest as the most important RGS protein involved in terminating signalling by the mu opioid receptor (although RGS4 and RGS17 are also involved), and is thought to be important in the development of tolerance to opioid drugs.
RGS9-2 is je od posebnog interesa kao najvažniji RGS protein u terminaciji signalizacije mi opioidnog receptora (mada RGS4 i RGS17 takođe učestvuju), i smatra se da je značajan u razvoju tolerancije za opioidne lekove.