Regulation of focal adhesion kinase by its amino-terminal domain through an autoinhibitory interaction.
We have investigated a role for the amino-terminal FERM-like domain of the focal adhesion kinase (FAK) as a negative regulator of its own activity and phosphorylation state. Deletion of the first 375 amino acids from the amino terminus of FAK increases its catalytic activity in vitro, its phosphorylation when expressed in mammalian cells, and the phosphorylation of a FAK substrate, paxillin. Deletion mutants are phosphorylated in suspension, suggesting that they are no longer regulated by adhesion. The amino terminus of FAK can interact with the kinase domain of FAK in vitro and in vivo, suggesting that it might act as an autoinhibitor of FAK activity. The amino terminus of FAK can act in trans to inhibit FAK phosphorylation when expressed in mammalian cells or to directly inhibit FAK activity in vitro. Expression of the amino terminus of FAK inhibits cell cycle progression in CHO cells, consistent with its inhibition of FAK phosphorylation and function in trans. A glutathione S-transferase fusion protein containing the cytoplasmic tail of the beta1 integrin stimulates FAK activity in vitro, suggesting that FAK could be regulated by molecular interactions with the amino terminus. Based on these and previous data, we propose a working model for activation of FAK in cell adhesion.
Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA.
Lee Ann
LA
Cooper
Tang-Long
TL
Shen
Jun-Lin
JL
Guan
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D016466:CHO Cells; D002453:Cell Cycle; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions / Q000235:genetics / Q000502:physiology; D066298:In Vitro Techniques; D019012:Integrin beta1 / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D008954:Models, Biological; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion
D019012:Integrin beta1; D011994:Recombinant Proteins; D004247:DNA; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases