Figure 7.

Characterization of PDGF β receptor phosphorylation. Extracts of Ba/F3 cells coexpressing the E5 protein, the full-length kinase-inactive receptor, and the truncated kinase-active receptor were immunoprecipitated with αPR, αPRex, or αE5, as indicated. The indicated samples also were treated with protein tyrosine phosphatase (PTPase). After gel electrophoresis, the immunoprecipitated receptor species were detected by probing the filter with anti-phosphotyrosine antibody (A) and αPR (B). The position of receptor species is indicated as described in the legend to Fig. 3.