PRKN and colorectal carcinoma: As shown in Fig. 4D,E, the assay readily detects mitophagy in CCCP-treated HEK-293 kidney epithelial cells, which are known to express endogenous Parkin31, 32, 43, 44, as well as in CCCP treated HCT-116 colorectal carcinoma cells co-transfected with Parkin.