FAK (Focal Adhesion Kinase or PTK2) is a non-receptor and non-membrane associated protein tyrosine kinase that is activated at the sites of cell-matrix adhesions and integrin clustering by auto-phosphorylation (at Tyr397), Src, and other tyrosine kinases. FAK mediates integrin-based cell signaling by transferring signals regulating cell migration, adhesion, and survival from the extracellular matrix to the cytoplasm.
FAK is overexpressed in many tumors, including those derived from the head and neck, colon, breast, prostate, liver, and thyroid. Furthermore, FAK overexpression is highly correlated with an invasive phenotype in these tumors. Inhibition of FAK signaling by overexpression of dominant-negative fragments of FAK reduces invasion of glioblastomas and ovarian cancer cells. FAK therefore represents an important target for the development of anti-neoplastic and anti-metastatic drugs.