Fig. 4.

Western blot analysis of the expression of G protein subunits in triple-infected Sf9 cells expressing wild-type (wt) rat adenine receptors or mutant constructs in addition to recombinant mammalian G proteins. Membrane preparations of infected Sf9 insect cells (3 μg) were separated in an SDS gel and transferred onto a nitrocellulose membrane. Protein bands of Gα_i2 (~45 kDa) and Gγ₂ (~8 kDa) were detected using antibodies against Gα_i1/i2 (1:2,000) and Gγ₂ (1:2,000), respectively. Asterisk in the upper panel (Gα_i1/i2 antibody): wt receptor was expressed without G proteins