$\backslash (3\backslash$mid $\backslash )$ Signal Transduction by G Protein$-$Coupled Receptors Termination of the response can occur through multiple processes. Desensitization $-$ by blocking active receptors from turning on additional G proteins. G protein$-$coupled receptor kinase $($GRK$)$ activates a GPCR via phosphorylation. Proteins called arrestins compete with G proteins to bind GPCRs$.$ Termination of the response is accelerated by regulators of $\backslash ($ G $\backslash )$ protein signaling $($RGSs$).$