FAK, phosphorylated (Tyr397), Human (Focal Adhesion Associated Protein Tyrosine Kinase, BC3) BioAssa

Focal Adhesion Kinase (FAK), also known as pp125FAK and FADK 1 (EC,2.7.1.112) is a non-receptor protein-tyrosine kinase that localizes to focal adhesions. FAK appears to be ubiquitously expressed among all mammalian tissues, with highest expression levels observed in brain tissue. 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. FAK's amino-terminal, which bears homology with the band 4.1 family of proteins, plays a role in mediating interaction with the cell membrane, the cytoskeleton, and integrin proteins. FAK's carboxyl-terminus, which contains the focal adhesion targeting (FAT) domain, mediates interaction with focal adhesion associated proteins, including talin and paxillin. FAK is activated by phosphorylation events in response to several stimuli. These stimuli include integrin clustering induced by cell adhesion or antibody cross-linking, G-protein coupled receptor (GPCR) occupancy by ligands such as bombesin or lysophosphatidic acid, or by LDL receptor occupancy. In response to integrin engagement, FAK is autophosphorylated at tyrosine residue 397. This autophosphorylation event creates high affinity binding sites for the SH2 domains of several important signaling proteins, including Src family members (c-Src and Fyn, which are recruited to sites of adhesion and subsequently activated), phosphatidylinositol-3-kinase, phospholipase-Cgamma and Shc. In addition to tyrosine 397, five other tyrosine residues are phosphorylated in response, including tyrosine residues 407, 576, 577, 861, and 925. , Studies performed in vitro suggest that c-Src is the activity that catalyzes the phosphorylation of these residues. Phosphorylation of tyrosine 925, an event which creates a binding site for the Grb2 SH2 domain, contributes to integrin-sitmulated activation of the -ERK2/mitogen-activated protein kinase pathway. FAK promoted phosphorylation of these substrates and subsequent recruitment of Crk are critical downstream signaling events of FAK. FAK is under investigation in several areas of research, including cell adhesion and migration studies, studies on migration in response to growth factors, differentiation, cell cycle, apoptosis, and cancer studies. FAK is overexpressed in breast, colon and thyroid cancers, possibly contributing to some features of the malignant phenotype (i.e., increased migration and invasion of surrounding stroma). The role of FAK in contributing to cells' resistance to apoptosis is also under investigation, as over-expression of FAK in Madin-Darby canine kidney cells has been found to render these cells resistant to apoptosis following loss of adherence. FAK [pY397] ELISA is designed to detect and quantify the level of FAK protein phosphorylated at tyrosine residue 397. This assay is intended for the detection of FAK [pY397] from lysates of human and mouse cells. Also available is a FAK (Total) ELISA kit, which quantifies FAK independently of phosphorylation status and allows normalization of phosphorylated FAK to total FAK. ,