FIGURE 10.

A model for how the phosphorylation Cool-1 regulates its interactions with Cat and focal complex assembly and disassembly. Serum, EGF, or the expression of v-Src stimulates the phosphorylation of Cool-1. Tyrosine phosphorylation leads to the dissociation of Cool-1 from Cat. This in turn enables Cat to bind paxillin, leading to its release from the plasma membrane and focal complex disassembly. Serum starvation and de-phosphorylation enhances the ability of Cool-1 to bind to Cat, which favors the association of paxillin with the membrane and its interaction with other focal complex (FC) proteins, thereby supporting focal complex assembly.