Hyperactivation of Ras1 deregulates Cdc42-GTP localization following pheromone stimulation.

<p>CRIB-GFP, a marker for Cdc42-GTP imaged following pheromone stimulation in indicated genotypes, representative images from Movies S5-8. CRIB-GFP is enriched at growing tips in all mitotically growing cells (0 μM). Following 2 h pheromone stimulation CRIB-GFP is enriched at a single tip in wild type cells enabling uni-directional growth to form a polarized conjugation tube. Cells containing hyperactivating Ras1 mutations display CRIB-GFP fluorescence at many discreet locations around the plasma membrane (asterix). These strains fail to coordinate a single site of active Cdc42 and attempt to elongate from multiple sites (arrows). Scale bar 10 μm.