Effect of human ankyrin repeat and suppressor of cytokine signalling (SOCS) box protein 9 (ASB9) on the mitochondrial membrane potential (ΔΨm). (a) Human embryonic kidney 293 (HEK293) cells that stably express null (empty vector), Myc-tagged ASB9, or ASB9ΔSOCS were trypsinised for 5 min and incubated in 50 nM tetramethylrhodamine ethyl ester (TMRE) with (full line) or without (dotted line) 200 nM carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) for 30 min at 37°C in the dark. The TMRE fluorescence in the cells was analysed by flow cytometry. The low fluorescence indicates a loss of ΔΨm. (b) The ΔΨm of peripheral blood mononuclear cells (PBMCs), RPMI 8226 cells, and KG-1 cells were analysed as described in (a).