As previous studies reporting the localization of ErbB1 or ErbB2 to mitochondria were performed using cells that either naturally overexpressed c-Src (breast cancer cells [43]) or were cotransfected with a c-Src construct (10T1/2 cells [41,42]), we undertook a separate set of experiments in which COS-7 cells were transfected with ErbB1-mCitrine, c-Src-mTurquoise and Tom20-mTagBFP. The gene discussed is ERBB2; the disease is breast cancer.