Characterization of Tyrosine Phosphorylation of Paxillin in Vitro by Focal Adhesion Kinase
Year: 1995
Type: article
Abstract: The concomitant tyrosine phosphorylation of the focal adhesion protein, paxillin, and the tyrosine kinase, focal adhesion kinase (FAK), in response to multiple stimuli including integrin-mediated cell adhesion suggests that paxillin phosphorylation is closely coupled to FAK activity. In the present study, we have identified a specific tyrosine residue within paxillin, tyrosine 118 (Tyr-118), that represents the principle site of phosphorylation by FAK in vitro. The identification of this site as a target for FAK phosphorylation was accomplished by immunoprecipitating FAK and performing in vitro kinase assays, using as substrate either glutathione S-transferase (GST)-paxillin fusion proteins containing truncations in paxillin sequence or fusion proteins with phenylalanine substitutions for tyrosine residues. GST-paxillin containing a phenylalanine substitution at Tyr-118 (Y118F) was not phosphorylated by FAK immunoprecipitates; however, this mutant was shown to bind FAK equally as well as the wild type fusion protein. As a first step toward assessing the function of paxillin phosphorylation on Tyr-118, a Y118F paxillin cDNA construct was transiently transfected into NIH 3T3 cells. Similar to wild type paxillin, mutated paxillin localized to focal adhesions, indicating that the phosphorylation of paxillin on Tyr-118 is not essential for the recruitment of paxillin to sites of cell adhesion.
Source: Journal of Biological Chemistry
Authors: Susan L. Bellis, John T. Miller, Christopher E. Turner
Institutions: State University of New York, SUNY Upstate Medical University
Language: English
Subfield: Immunology and Allergy
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1969689864