Examples of reorientation and its simulation by computational model v.2. (A and B) Time-lapse images of MATa cells expressing in situ–tagged Ste2-GFP reorienting in mating mixtures. The fluorescent images show the localization of Ste2-GFP as MATa cells reorient. The filled arrowheads indicate the Ste2-GFP crescent at the initial CS (0') and after reorientation to the second CS. The closed yellow arrowheads indicate the tracking Ste2-GFP crescents. The plots show the distribution of Ste2-GFP on the PM at each time point. The dashed blue lines mark the position of the first CS; the dashed green lines mark the position of the leading peak during reorientation; the dashed red lines mark the position of the CS after reorientation. (A) Reorientation assay. MATa cells were grown to mid-log phase and treated with isotropic pheromone until they started shmooing. The treated cells were washed to remove exogenous pheromone, mixed with an equal number of MATα cells, and imaged until they formed zygotes. A representative reorienting shmoo is shown. (B) Spontaneous reorientation in vivo. An example of a MATa cell that initially oriented toward a potential partner (α1) before reorienting and mating with another (α2). (C) Outputs from the standard model challenged with a change in gradient direction. The direction of the pheromone gradient was rotated 90° at 201 min. The dashed black lines in the lower gradient panel indicate the position of the original gradient source. The dashed green boxes indicate the start of tracking and reorienting; the dashed red boxes indicate end of tracking.