Fig. 9

Mitochondrial ETC-mediated reduction of CysSSH. a, b Sulfide metabolite profiling for the reaction of the recombinant human CARS2 in vitro (a) and of CARS2 expressed in HEK293T cells (b). c–h Changes in amounts of CysSSH (ΔCysSSH) and HS⁻ (ΔHS⁻) induced by complex III inhibition by antimycin A c–e or by mitochondrial DNA (mtDNA) elimination induced by ethidium bromide (f–h) in WT and CARS2 KO HEK 293 T cells. The values of CysSSH and HS⁻ shown in b–h indicate the quantity of each compound produced in the cells in a manner dependent on CARS2 expression, which was determined by subtracting each amount in CARS2 KO HEK293T cells from that in the WT cells, after quantification of each metabolite via HPE-IAM labeling LC-MS/MS analysis. e, h Stoichiometric alterations (conversion) between CysSSH and HS⁻ in cells by the ETC inhibition. i Schematic diagram of ETC-mediated CysSSH reduction to form HS⁻ and possible further conversion to S₂O₃ ²⁻. The data are means ± s.d. (n = 3). *P < 0.05; **P < 0.01; N.S., not significant