Figure 4.
Phosphorylation of purified Gβγ reduces its association with purified GRK2. In vitro phosphorylation of purified Gβγ protein was accomplished using ATP and the catalytic subunits of PKC and PKA. (A) Autoradiography of purified Gβγ following incubation with [γ-32P]ATP in the absence (lane 1) or presence (lane 2) of kinase catalytic subunits. Both catalytic subunits were used to mimic the chronic morphine-induced phosphorylation of Gβ. (B) Western analysis of recombinant GRK2 protein in Gβ immunoprecipitate. Immunoprecipitation was performed following incubation of recombinant GRK2 protein with nonphosphorylated (lane 1) or phosphorylated (lane 2) purified Gβγ protein. All procedures were performed as described in Materials and Methods. Figure is representative of four experiments.