Rabbit Anti-Human FAK (phospho Tyr576) monoclonal antibody for FC, ICC, IHC-P, IF. 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 a central role in cell spreading, differentiation, migration, cell death and acceleration of the G1 to S phase transition of the cell cycle. Regulation of FAK includes phosphorylation at multiple tyrosine and serine residues. Increased FAK tyrosine phosphorylation occurs upon integrin engagement with fibronectin.