title: Tyrosine phosphorylation of paxillin alpha is involved in temporospatial regulation of paxillin-containing focal adhesion formation and F-actin organization in motile cells.
abstract: Temporal and spatial regulation of actin-based cytoskeletal organization and focal adhesion formation play an essential role in cell migration. Here, we show that tyrosine phosphorylation of a focal adhesion protein, paxillin, crucially participates in these regulations. We found that tyrosine phosphorylation of paxillin was a prominent event upon integrin activation during epithelial-mesenchymal trans-differentiation and cell migration. Four major tyrosine phosphorylation sites were identified, and two of them were highly inducible upon integrin activation. Paxillin exhibits three distinct subcellular localizations as follows: localization along the cell periphery colocalized with circumferential actin meshworks, macroaggregation at focal adhesions connected to actin stress fibers, and diffuse cytoplasmic distribution. Tyrosine phosphorylation of paxillin localized at the cell periphery and focal adhesions was shown using phosphorylation site-specific antibodies. Mutations in the phosphorylation sites affected the peripheral localization of paxillin and paxillin-containing focal adhesion formation during cell migration and cell-cell collision, accompanied by altered actin organizations. Our analysis indicates that phosphorylation of multiple tyrosines in paxillin alpha is necessary for the proper function of paxillin and is involved in the temporospatial regulation of focal adhesion formation and actin cytoskeletal organization in motile cells.
authors.affiliation: Department of Molecular Biology, Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Yano
authors.forename: H
authors.initials: H
authors.lastname: Uchida
authors.forename: S
authors.initials: S
authors.lastname: Hashimoto
authors.forename: E
authors.initials: E
authors.lastname: Schaefer
authors.forename: H
authors.initials: H
authors.lastname: Sabe
mesh_terms: D000199:Actins / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D051416:Focal Adhesion Protein-Tyrosine Kinases; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D009154:Mutation; D051419:Paxillin; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050717:Retinoblastoma-Like Protein p130; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D000199:Actins; D003598:Cytoskeletal Proteins; D008164:Luminescent Proteins; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D050717:Retinoblastoma-Like Protein p130; D049452:Green Fluorescent Proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases