Modelling of Yeast Mating Reveals Robustness Strategies for Cell-Cell Interactions
Fig 8
Role of Bar1 in mating discrimination with background α-factor.
(A) Five-cell mating discrimination simulations with background α-factor in the presence and absence of Bar1. Four α-cells are arranged in a square with one a-cell in the center. One α-cell makes α-factor (α-factor producer, top right corner) and the other three cells do not. Background α-factor source was set to C = 50. There are two sample simulations for bar1Δ a-cells (left), and two sample simulations for Bar1+ a-cells (right). ME is mating efficiency, and MD is mating discrimination. Bar1 was secreted in a polarized fashion. The second row shows the α-factor profiles for one sample (left) simulation from each group. The third row shows the α-factor profiles along the top-right to bottom-left diagonal for one example (yellow dotted line). There is an early (T = 50s) and late (T = 570s) time point for each simulation with α-factor concentration indicated by the shading (color bar). Pheromone profiles show a steeper gradient in Bar1+ a-cell simulations; troughs represent the cell body which excludes α-factor. (B) Mating location plots for Bar1+ a-cells (green) or bar1Δ (red) in five-cell mating discrimination simulations. Each circle (correct MD) or cross (incorrect MD) symbol represents the polarisome location of the a-cell at the time of mating. The α-cell producing α-factor was in the top-right quadrant. The Bar1+ cells showed significantly better mating discrimination (MD) than the bar1Δ cells (p < 0.05, Fisher’s Exact Test).