Figure 4. Cbl mutant proteins exhibit prolonged protein turnover and are associated with increased phosphorylated EGFR levels upon EGF stimulation.
Panel (a) HEK293 cells transfected with plasmids encoding EGFR in combination with HA-Cbl(WT) or HA Cbl(p.Y371H) were serum starved for 18 h followed by 15 min EGF (50 ng/ml) stimulation. Cells were then washed and maintained in serum-free media for the indicated periods of time. Equal amounts of whole cell extracts were resolved on SDS-PAGE and immunoblotted with the indicated antibodies. Panel (b) HEK293 cells transfected with plasmids encoding EGFR in combination with HA-Cbl(WT) or HA-Cbl(p.Y371H) were serum starved for 18 h followed by 15 min EGF (50 ng/ml) stimulation. Cells were then washed and maintained in serum-free media with (+) or without (-) MG132 for the indicated periods of time. Equal amounts of whole cell extracts were resolved on SDS-PAGE and immunoblotted with the indicated antibodies.