Figure 6.

Working model for how Y118-Paxillin phosphorylation status regulates cell migration in the in vitro cell culture and in vivo conditions. Top: Under in vitro cell culture conditions, FAK phosphorylates Paxillin on Y118, leading to high levels of Y118-Paxillin phosphorylation in migrating cells. In migrating cells in vivo, FAK levels are low, and Y118-Paxillin lacks phosphorylation. Bottom: Expression of the non-phosphorylatable Y118F-Paxillin leads to reduced cell migration in vitro compared with cells expressing the Y118E-Paxillin phosphomimetic, likely through reduced focal adhesion disassembly rates and reduced CRKII-DOCK180/RacGEF recruitment to Paxillin-positive focal adhesions. However, in vivo, cells expressing the non-phosphorylatable Y118F-Paxillin exhibit increased cell migration, likely through increased focal adhesion disassembly rates, and increased recruitment of CRKII-DOCK180/RacGEF to Paxillin-positive focal adhesions.