Fig. 1. Phenotypic comparison of the two cell lines studied. (A) Western blotting. Left: the effect of temperature shift on v-Src content (anti-avian Src antibody EC10) and activation (p-Y⁴¹⁸ phosphopeptide-specific antibodies). Right: evidence that pharmacological inhibitors used below do not interfere with v-Src expression and/or activation. (B) Immunolocalization of v-Src and paxillin in comparison with actin filaments. Rat-1/tsLA29 and MDCK/tsLA31 cells were cultured at low density on glass slides and incubated for 20 hours at non-permissive (40°C; upper row) or permissive temperature (34°C; lower row) for v-Src kinase activity, then fixed and permeabilised. v-Src was labelled by anti-avian Src-specific mouse monoclonal IgG_2b antibody (clone EC10), and revealed by Alexa 488-labelled goat anti-mouse IgG₂ antibodies (green). Paxillin, a focal adhesion marker, was detected by mouse monoclonal IgG₁ antibody (clone 165), and revealed by Alexa 647-labelled goat anti-mouse IgG₁ antibodies (blue). F-actin was decorated by Alexa 568-phalloidin (red). Cells were analysed by confocal microscopy. Scale bars: 10 µm.