Correction for Brewer et al., Mechanism for activation of mutated epidermal growth factor receptors in lung cancer
Proceedings of the National Academy of Sciences of the United States of America
Fig. 7 . Lung-cancer-associated EGFRs induce hyperphosphorylation of coexpressed ErbB-2 by virtue of superacceptor activity. (A) Coexpression of lung-cancerassociated mutant ICDs with WT ErbB-2 ICDs in HEK293 cells results in hyperphosphorylation of the ErbB-2-ICD population as assessed by anti-ErbB-2 immunoprecipitation and subsequent Western blotting for anti-ErbB-2-pY1221/22. Coexpression of WT EGFR-ICD with ErbB-2-ICD results in a slight increase in phospho-ErbB-2, whereas coexpression of
... s coexpression of either lung-cancer-associated ICD (LR or LRTM) with ErbB-2 results in hyperphosphorylation of ErbB-2-ICD (lanes 4, 8, and 12, respectively). Unlike lung-cancer-associated EGFRs containing the donor-enforcing I682Q mutation, combination of lung-cancer-associated EGFR-ICDs containing acceptor-enforcing V924R mutation with ErbB-2-ICD results in hyperphosphorylation of ErbB-2-ICD at levels equivalent to the combination of ErbB-2-ICD with lung-cancer-associated parent EGFR-ICDs (lane 10 compared with lane 8 and lane 14 compared with lane 12). (B) Coexpression of intact WT EGFR with intact ErbB-2 results in an increase in tyrosine-phosphorylated ErbB-2 relative to ErbB-2 expressed alone, whereas ErbB-2 coexpression with lung-cancer-associated mutant EGFR (LRTM) results in a significant increase in phospho-ErbB-2 levels. Treatment of cells coexpressing ErbB-2 and EGFR-L834R/T766M with WZ-4002 in the presence of EGF abrogates the EGFR mutant-induced hyperphosphorylation of ErbB-2 (compare lane 16 to lane 11). A comparatively less dramatic effect on ErbB-2 tyrosine phosphorylation is observed for cells coexpressing ErbB-2 and WT EGFR treated with WZ-4002 in the presence of EGF (compare lane 15 to lane 9). (C) Coexpression of 0.1 μg myc-tagged lung cancer-associated mutant ICD with 1.0 μg of Flag-tagged WT EGFR or ErbB-2-ICD results in additive increases in pAkt or pStat-3 levels compared with singly expressed ICDs, whereas a synergistic increase in pErk levels is observed upon coexpression (compare lanes 2-4 to lanes 6 and 7).