FIG. 3.

E. coli invasion of HBMEC stimulates the tyrosine phosphorylation and kinase activity FAK in HBMEC and the phosphorylation of paxillin and its association with FAK. Cell lysates obtained after treatment of HBMEC with either E. coli E44 or HB101 or Listeria for different periods of time (minutes) were immunoprecipitated (IP) with either anti-FAK antibody (A and C) or antipaxillin antibody (B) and subjected to Western blotting (IB) with antiphosphotyrosine antibody (pY; A and B), anti-FAK antibody (FAK; A and C), or antipaxillin antibody (PAX; B and C). (D) Cell lysates were immunoprecipitated with anti-FAK antibody and subjected to in vitro kinase assay as described in Materials and Methods. The immune complexes were also subjected to immunoblotting with anti-FAK antibody. C, control.