The gβγ Dimer as a Novel Source of Selectivity in G-Protein Signaling: GGL-ing AT CONVENTION

The effects of purified Gβ₅–R7 dimers on the GTPase activity of Gi and Gq family Gα subunits. A. Recombinant epitope-tagged Gβ₅–R7 dimers were expressed in insect cells and purified; purified products are shown on a coomassie blue-stained SDS-PAGE gel. B. Relative steady-state GTPase activities of various purified Gα subunits reconstituted with receptors in proteoliposomes were determined in the presence of Gβ₅–R7 dimers. Gα_o, Gα_i1, Gα_i2, and Gα_i3 (with Gβ₁γ₂) were reconstituted in phospholipid vesicles with the M2 muscarinic receptor, and Gα_q and Gα₁₁ (with Gβ₁γ₂) were reconstituted with the M1 muscarinic receptor (62).