FIGURE 8:

Schematic of the Bni1p regulatory network. Cdc42p interacts directly with Bni1p (1), but this interaction is not necessary for Bni1p regulation. Two other “polarisome” proteins (Spa2p and Bud6p) are localized to sites of Cdc42p action (2) and interact with Bni1p (3), but even in combination these pathways (1–3) are dispensable for Bni1p regulation. We identified a novel path (4) from Cdc42p to Bni1p via the Cdc42p effector Gic2p, which was previously found to interact with Spa2p and Bud6p (5). Genetic interactions suggest that paths 1, 2–3, and 4 act in parallel, and biochemical findings suggest that paths 4 and 5 operate in parallel. Solid lines indicate interactions shown by in vitro biochemical assays. Dashed lines indicate interactions identified with immunoprecipitation and/or cofractionation. Dotted lines with question marks indicate interactions suggested by colocalization.