Fig. 6.

Association of PI3K with ErbB-3 does not require phosphotyrosine sites within the EGFR cytoplasmic tail. (Upper) PC9 cells expressing the indicated EGFR variants were transduced with control or EGFR shRNA vectors. At 36 h after transduction, 1 μM erlotinib was added to an aliquot of the PC9-GFP cells that had been transduced with the shCTRL vector. At 48 h after transduction, extracts were prepared and immunoblot analysis was performed with the indicated antibodies. (Lower) The p85 PI3K subunit was immunoprecipitated from 1 mg extract for each sample. Immunoprecipitates were probed with antibodies against phosphotyrosine, ErbB-3 or p85.