Fig. 4.
Coupling of taste receptors to G protein α-subunits in NCI-H716 cells. Membranes from NCI-H716 cells were preincubated with the indicated concentrations of glucose and sucrose for 10min at 25°C in the presence of 5–10μCi [32P] GTP-azidoanilide, then irradiated to cross link the GTP analog to G proteins. G protein-specific immune complexes (anti-Gα-gustducin, anti-Gαi1,2, anti-Gαs, and control IgG) were separated by SDS/PAGE, transferred to membranes, and autoradiographically imaged. A positive control for G protein activation is shown in SI Fig. 12.