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. 2022 Feb 2;23(3):1726. doi: 10.3390/ijms23031726

Figure 1.

Figure 1

Protein structure and multiple binding partners of focal adhesion kinase. Focal adhesion kinase (FAK) is composed of an amino-terminal region containing a protein band 4.1–ezrin–radixin–moesin (FERM) domain, followed by a central kinase domain and a carboxy-terminal focal adhesion targeting (FAT) domain. Three proline-rich regions (PRRs) are embedded in the linker regions between these domains. Tyr397, Lys454, and His58 are important for FAK activation. Phosphorylation (P) occurs on several important tyrosine residues, as indicated, including the autophosphorylation site Tyr397, the Tyr576/577 residues in the activation loop of the kinase domain, and Tyr861, Tyr925, and Tyr1007 in the C-terminal domain. There are one nuclear export signal (NES) sequence and one nuclear localization signal (NLS) sequence in the FERM domain of FAK and one NES sequence in the kinase domain. Many proteins bind to FAK, regulating its functions or forming a complex, which is necessary for distinct biological processes. Phosphorylated Tyr397 is a well-known binding site for Src homology 2 (SH2) domain-containing proteins. The PRRs provide proline-rich sequences that bind with Src homology 3 (SH3) domain-containing proteins. The FAT domain is required to target FAK to the focal adhesion via binding to talin and paxillin.