A truncated FAK lacking the FERM domain displays high catalytic activity but retains responsiveness to adhesion-mediated signals.
In order to determine the role of the FERM domain in the regulation of FAK phosphorylation at Tyr-397, the major autophosphorylation site, we generated a truncated FAK lacking a region of the N-terminus corresponding to amino acids 1-384 (FAKDelta384). FAKDelta384 showed a striking increase in phosphorylation, as compared with wild type FAK, in lysates of either HEK 293 or FAK-/- cells. Interestingly, the truncated form of FAK lacking the N-terminal domain retains responsiveness to integrin-mediated signals, as judged by its dephosphorylation by holding cells in suspension and by the recovery of the phosphorylation when replating the cells on fibronectin. We propose a model in which removal of FERM-mediated auto-inhibition is important to increase FAK catalytic activity but the translocation and clustering of this enzyme at the focal adhesions is required for maximal phosphorylation at Tyr-397.
Jácamo
Rodrigo O
RO
Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center, Molecular Biology Institute, University of California at Los Angeles, USA.
Rozengurt
Enrique
E
D000818:Animals; D002384:Catalysis; D002448:Cell Adhesion / Q000502:physiology*; D002460:Cell Line; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013329:Structure-Activity Relationship
D016023:Integrins; D011994:Recombinant Proteins; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496051:Ptk2 protein, mouse