Regulation of ErbB2 Receptor Status by the Proteasomal DUB POH1
Figure 1
ErbB2 escapes EGF induced down-regulation.
A, Comparison of ErbB2 receptor levels in HeLa and SKBr3 cells. Cell lysate samples corresponding to the indicated number of cells were separated by SDS-PAGE and immunoblotted with ErbB2 antibodies and IR800-coupled secondary antibodies. The relative amount of ErbB2 per cell was calculated based on Odyssey scans as discussed in Materials and Methods. B, HeLa, HEK293T (H293T), A549, and DU145 cells were stimulated with 100 ng/ml EGF for 2 hours and lysed in parallel with unstimulated cells. The lysate was subjected to SDS-PAGE and immunoblotting with EGFR, ErbB2, and tubulin antibodies. EGFR is down-regulated after 2 hours stimulation, but ErbB2 remains stable. C, HeLa and SKBr3 cells were treated with 100 ng/ml EGF for 1 or 2 hours and analysed by immunoblotting with EGFR and ErbB2 antibodies. No EGFR was detected in SKBr3 cells. Note that EGFR antibody (2232) cross-reacts with high levels of ErbB2 in SKBr3 cells.