TF-1 cell adhesion to fibronectin induces tyrosine phosphorylation of pp125^FAK and paxillin. (A) TF-1 cells in suspension (lane 1), plated on BSA-coated wells (lane 2), or plated on fibronectin-coated wells (lane 3) were incubated 15 minutes at 37°C. Cells were lysed and subjected to immunoprecipitation with anti-p-Tyr MoAb. Immunoprecipitates were subjected to immunoblotting with anti-p-Tyr MoAb. (B) TF-1 cells in suspension culture (lane 1), plated on BSA-coated wells (lane 2), or plated on fibronectin-coated wells (lane 3, 4) were incubated 15 minutes at 37°C. Cells were lysed and subjected to immunoprecipitation with anti-pp125^FAK MoAb (lanes 1 to 3) or control isotype matched IgG (lane 4). Immunoprecipitates were subjected to immunoblotting with anti-p-Tyr MoAb (upper panel) and anti-pp125^FAK polyclonal antibody (lower panel). (C) TF-1 cells in suspension culture (lane 1), plated on BSA-coated wells (lane 2) or plated on fibronectin-coated wells (lanes 3 and 4) were incubated for 15 minutes at 37°C. Cells were lysed and subjected to immunoprecipitation with antipaxillin MoAb (lanes 1 to 3) or control isotype matched IgG (lane 4). Immunoprecipitates were subjected to immunoblotting with anti-p-Tyr MoAb (upper panel) and antipaxillin MoAb (lower panel). Molecular mass markers are in kD. Similar results were obtained in three independent experiments.