Fig. 4. Expression of 480-Cbl does not affect PDGF receptor phosphorylation and polyubiquitylation. Wild-type, c-Cbl- and 480-Cbl-expressing NIH 3T3 cells were lysed following serum starvation or after 3 and 10 minutes of PDGF activation, as indicated. Aliquots of the lysates were immunoprecipitated with anti-PDGF receptor antibodies and probed by western blot with anti-phosphotyrosine (A), anti-ubiquitin (B) or anti-PDGF receptor (C) following SDS-PAGE.