Figure 5.

The receptor can polarize in the absence of tropomyosin function. (A) Representative fluorescent images of Ste2-GFP localization in tpm1-2 tpm2 temperature-sensitive cells. G1-synchronized cells were treated with 30 nM pheromone at the permissive temperature (0 time for the 23°C cultures) or 5 min after the shift to restrictive temperature (0 time for the 37° cultures). Images were acquired every 15 min. Arrows indicate Ste2-GFP crescents. (B) Quantification of Ste2-GFP polarization in tpm1-2 tpm2-2 cells at the permissive and restrictive temperatures. The bar graphs represent the mean polarity index ± SD at each time point (n = 15). *p < 0.01 and **p < 0.001 for the comparisons of treated cells to 0 min.