G protein βγ complex translocation from plasma membrane to Golgi complex is influenced by receptor γ subunit interaction

On activation of a receptor the G protein beta gamma complex translocates away from the receptor on the plasma membrane to the Golgi complex. The rate of translocation is influenced by the type of gamma subunit associated with the G protein. Complementary approaches - imaging living cells expressing fluorescent protein tagged G proteins and assaying reconstituted receptors and G proteins in vitro - were used to identify mechanisms at the basis of the translocation process. Translocation of G beta gamma containing mutant gamma subunits with altered prenyl moieties showed that the differences in the prenyl moieties were not sufficient to explain the differential effects of geranylgeranylated gamma 5 and famesylated gamma 11 on the translocation process. The translocation properties of G beta gamma were altered dramatically by mutating the C terminal tail region of the gamma subunit. The translocation characteristics of these mutants suggest that after receptor activation, G beta gamma retains contact with a receptor through the gamma subunit C terminal domain and that differential interaction of the activated receptor with this domain controls Goy translocation from the plasma membrane. (c) 2006 Elsevier Inc. All rights reserved.