Autophagy receptors are recruited to intact mitochondria in Drp1 KO cells, enhancing mitophagic flux. (A and B) FACS-based mito-Keima assay dot plots of Tet ON: ΔOTC-expressing HeLa cells expressing YFP-Parkin with or without DOX treatment (A) or OA treatment (B) for the indicated time points with or without a Drp1 KO background. The y axis represents the fluorescence emission of mito-Keima at pH 4.0 (lysosome) versus the x axis, which indicates mito-Keima emission at pH 7.0 (mitochondria). The percentage of cells within the boxed regions are indicated. (C) Tet ON: ΔOTC-expressing Drp1 KO HeLa cells expressing YFP-Parkin (green), mCherry-optineurin, mCherry-LC3, or mito-RFP (red) were treated with DOX for 48 h and then processed for indirect immunofluorescence with an antibody to TOM20, PDH, ubiquitin (blue), or p62 (red). Each row represents a different cell. (D and E) Control or Drp1 KO HeLa cells were treated with actinonin for 6 h, fixed, and stained with an antibody to TOM20 (red) and ubiquitin (D) or p62 (blue; E). (F) Drp1 KO HeLa cells expressing YFP-Parkin (green) and mito-RFP (red) were treated with actinonin for 6 h and imaged live for the indicated times. Bars, 10 µm.