Figure 2.

Effects of injected G protein subunits on endocytosis. One hour after injection, cells were incubated with Texas Red-conjugated transferrin (25 μg/ml, Molecular Probes) for 5 min at 37°C. Cells were then chilled on ice, washed, and fixed with 3% paraformaldehyde. Panels A, C, E, G, and I show fluorescence of fluorescein-dextran and thus demonstrate which cell in the field was injected with buffer (A), myrG_iα1 (C), myrG²⁰³AG_iα1 (E), myrG²⁰³AG_iα1 plus β₁γ₂ (G), or myrQ²⁰⁴LG_iα1 (I). Panels B, D, F, H, and J show accumulation of Texas Red-transferrin by all cells in the same field. (Bar = 15 μm.)