[5] It has been shown that when FAK was blocked, breast cancer cells became less metastatic due to decreased mobility.

[6] The PTK2 gene encodes a cytosolic protein tyrosine kinase that is found concentrated in the focal adhesions that form among cells attaching to extracellular matrix constituents.

Additional components of focal adhesions include actin, filamin, vinculin, talin, paxillin, tensin[11] and RSU-1.

FAK is phosphorylated in response to integrin engagement, growth factor stimulation, and the action of mitogenic neuropeptides.

[12][13] Integrin receptors are heterodimeric transmembrane glycoproteins that cluster upon ECM engagement, leading to FAK phosphorylation and recruitment to focal adhesions.

[17] Throughout apoptosis, FAK is an important contributor to cell rounding, loss of focal contacts and apoptotic membrane formations such as blebbing,[18] which involves contracting the cortical actin ring and is followed by chromatin condensation and nuclear fragmentation.

[22] The function of the amino-terminal domain is less clear, but it has been shown to interact with the beta-1 integrin subunit in vitro and is thought to be involved in the transduction of signals from ECM-integrin clusters.

This 4.1 band domain binds to the cytoplasmic region of transmembrane proteins including glycophorin C, actin and spectrin.

[26] FAK mRNA levels are elevated in ~37% of serous ovarian tumors and ~26% of invasive breast cancers, and in several other malignancies.