Biophysical model of polarisome focusing. (A) Cortical PNCs are moved by Myo2 motor proteins along actin cables. (B) Model simulation shows transition of a random initial condition with 0–5 particles per mesh node (left) to the single focused polarisome (right). Actin cables are shown by arrows. Color encodes number of particles per node as indicated by the color bar. Entire simulation is shown in Video 5. (C) Time course of the calculated radius of the polarisome particle cluster. (D and E) Probability to form a single stable polarisome as a function of indicated model parameters. Color encodes the probability as indicated by the color bar. (F) Left: Fluorescence microscopy of WT, bni1_Δ825–990, spa2_Δ1200–end, or msb3Δ msb4Δ cells expressing Spa2-GFP. Right: Polarisome distributions of the cells from the left panel (n_WT = 234, n_{bni1Δ825–990} = 151, n_{spa2Δ1200–end} = 154, n_{msb3Δ msb3Δ} = 230) were classified as either focused (gray) or cortically spread (spread, blue). Scale bar: 5 µm.