Figure 1.

CysSSH formation, protein polysulfidation and regulation of mitochondrial function mediated by the novel CysSSH‐producing enzyme CARS. CARS produces CysSSH from cysteine. CysSSH‐producing activity of CARS is critically involved in translation‐coupled protein polysulfidation. Protein polysulfidation may be involved in the regulation of protein functions, such as expression of enzyme activity and maintenance of protein structure. CysSSH produced by mitochondrial CARS2 mediates the sulfur‐mediated bioenergetics in mitochondria (sulfur respiration). The molecular mechanisms underlying sulfur respiration are shown in Figure 5.