Updated FTP location. HEK293 cells that stably express wild-type (WT), E229/231/233K (KKK), or I225P mutant PHB2(V1) fused at C-terminus with the biotin ligase from A. aeolicus were incubated with 100 μM biotin for 18 h. The mitochondrial fractions were lysed in RIPA buffer, and the clarified supernatants were incubated with streptavidin-agarose beads for 2 h at 4° C. Proteins on the beads were digested by adding trypsin/Lys-C mix for 16 h at 37° C and analyzed by LC-MS/MS. Label-free quantification was performed using Proteome Discoverer 2.2 software.