FIGURE 4.

Western blots using antibodies against Gpa1p and Ste4p (gifts from Dr. Orna Resnekov, Molecular Sciences Institute) in strains overexpressing all three subunits of G proteins and varying levels of receptor expression levels. A, short exposure (2.5 min) with strains overexpressing G proteins immunoblotted with anti-Ste4p (left panel) or anti-Gpa1p (right panel). Gpa1p runs at ∼54 kDa and Ste4p runs at ∼52 kDa. gpa1-Δ and ste4-Δ strains are shown as negative controls. For each Ste2p expression level, a strain expressing wild-type levels of G proteins is shown as a control. The asterisk indicates a cross-reacting protein in the right panel. B, wild-type level of Gpa1p, expressed from chromosomal GPA1⁺, is visible at longer exposure times (20 min). The asterisk indicates the mobility of a cross-reacting protein. The density of the overall image in B was electronically adjusted for improved visibility. C, loading control immunoblotted with anti-glucose-6-phosphate dehydrogenase (G6PDH).