Two G12 family G proteins, Gα12 and Gα13, show different subcellular localization

The Gα subunits of the G12 family of heterotrimeric G proteins, Gα12 and Gα13, are closely related in sequences and some effectors, but they often act through different pathways or bind to different proteins. We have examined subcellular distribution of these two G proteins and found that endogenous Gα12 and Gα13 localize in membrane and cytoplasmic fractions, respectively. Exogenously expressed Gα12 and Gα13 also localize in membrane and cytoplasmic fractions, respectively, in COS-7 cells. Stimulation of lysophosphatidic acid receptor coupled to Gα13 markedly promotes the translocation of Gα13 from cytoplasm to membrane. This different localization of Gα12 and Gα13 may explain some of the nonoverlapping actions of Gα12 and Gα13.