Fig. 3.
Model for βγ translocation. (A) Heterotrimers with lipidated α- and γ-subunits interact stably with the plasma membrane. (B) On receptor activation, the βγ-complex dissociates from the α-subunit. The single prenyl moiety on the γ-subunit facilitates membrane interaction but is insufficient for stable membrane binding of βγ, which diffuses throughout the cytosol and binds transiently to both the plasma membrane and intracellular membranes. A pool of free βγ is available to participate in the G-protein activation cycle at the plasma membrane as long as receptors are active. (C) On receptor deactivation, αGDPβγ heterotrimers rapidly accumulate at the plasma membrane, depleting the intracellular pool of βγ.