Fig. 6. Effect of Gβ^P− on receptor polarization.

(A and B) Isotropic conditions. Gβ cells and Gβ^P− cells expressing the receptor reporter Ste2-GFP were treated with pheromone at time zero and with LatA after global receptor internalization (15 min). (A) Representative images of the indicated cells to visualize Ste2-GFP. Arrowheads indicate Ste2-GFP crescents. (B) Polarity Indices (PIs) for the cells represented in (A) were measured as described for Fig. 2D. Data are means ± SEM of at least 30 cells of each strain from three experiments. *P < 0.03. (C and D) Mating mixtures. (C) Time-lapse images of mating Gβ cells and Gβ^P− cells showing Ste2-GFP localization. Insets show heat map images analyzed using the BudPolarity Matlab program (61), which quantifies signal intensity along the long axis of the cell. (D) Output BudPolarity trace of the pictured cell (inset). Receptor polarization in the cells represented in (C) was quantified by dividing the peak fluorescence signal at the plasma membrane by the minimum fluorescence at the plasma membrane before morphogenesis became apparent. Mean polarization values ± SEM were 1.76 ± 0.14 and 1.28 ± 0.07 for Gβ cells and Gβ^P− cells, respectively (P < 0.007). Data are means ± SEM of at least 17 cells of each strain from two independent experiments.