Figure 8.

Expression of PD-resistant mutant Arg-T314I permits tyrosine phosphorylation in the presence of PD. (a–i) Images of 3T3 cells transfected with Arg-YFP or Arg-T314I-YFP. Cells were infected with EPEC for 5 h and then either treated with carrier or 10 μM PD for 1 h postinfection. Cells were stained with DAPI to recognize EPEC and α-4G10-Cy5 to recognize phosphotyrosine. Note that P-Tyr staining colocalizes with Arg-YFP (c). Note also that P-Tyr staining is no longer evident upon addition of PD to cells overexpressing Arg-YFP(f) but that P-Tyr staining persists in cells expressing Arg-T314I-YFP (i). Thus, like Abl, Arg is sufficient among tyrosine kinases for tyrosine phosphorylation. Bars, 5 μm.