title: Involvement of cortactin and phosphotyrosine proteins in cell-cell contact formation in cultured bovine corneal endothelial cells.
abstract: Phosphotyrosine proteins involvement, particularly cortactin, was studied in cell-cell contacts of cultured bovine corneal endothelial (BCE) cells. These proteins, including alpha-catenin, vinculin and cortactin, are localized at cell-cell contacts separate from the cortical actin ring. Approximately 50% of cortactin isoforms p80 and p85 were associated with the Triton-insoluble fraction while phosphotyrosine proteins were in the soluble fraction. Disruption of cell-cell contacts by EDTA treatment was associated with a decrease in cortactin isoforms p80 (26%) and p85 (57%). Cortactin isoform p85 was phosphorylated at Y466, expressed in reattaching cells and associated with the Triton-soluble fraction, whereas cortactin isoform p80 was phosphorylated at Y421 and associated with the Triton-insoluble fraction. In sub-confluent cultures, pY421-cortactin was localized at the leading edge and pY466-cortactin at a perinuclear area. In confluent cultures both pY466- and pY421-cortactin isoforms were localized at the cell-cell contacts. In conclusion, in BCE cells, the most prominent appearance of cortactin was at the cell-cell contacts separate from the cortical actin ring. Isoform p80 was phosphorylated at Y421 and associated with the Triton-insoluble fraction and isoform p85 was phosphorylated at Y466 and associated with the Triton-insoluble fraction.
authors.affiliation: Goldschleger Eye Research Institute and the Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Lily
authors.initials: L
authors.lastname: Kredy-Farhan
authors.forename: Shlomo
authors.initials: S
authors.lastname: Kotev-Emeth
authors.forename: Naphtali
authors.initials: N
authors.lastname: Savion
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D051356:Cortactin / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004728:Endothelium, Corneal / Q000166:cytology* / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D019000:Phosphotyrosine / Q000378:metabolism; D016596:Vinculin / Q000378:metabolism*; D051178:alpha Catenin / Q000378:metabolism*
chemical_list: D000199:Actins; D051356:Cortactin; D003598:Cytoskeletal Proteins; D051178:alpha Catenin; D016596:Vinculin; D019000:Phosphotyrosine