Rabbit Anti-Human phospho FAK (Tyr397) monoclonal antibody for WB. Focal Adhesion Kinase (FAK) is a 125 kDa non-receptor protein tyrosine kinase that acts as a substrate for Src and is a key element of integrin signaling. FAK plays an important role in cell spreading, differentiation, migration, cell death, and acceleration of the G1 to S phase transition of the cell cycle. Tyrosine 397 is the autophosphorylation site of FAK, and involved in its initial activation. This phosphorylated site binds Src family SH2 domains and the p85 subunit of PI3-Kinase, and activates cell migration and invasion.