Mechanisms of S-nitrosothiol formation and selectivity in nitric oxide signaling

► Nitric oxide can signal through S-nitrosation of cysteine residues. ► S-Nitrosation can occur through NO oxidation to N2O3 or radical recombination. ► Cytochrome c was recently discovered to catalyze the synthesis of GSNO. ► Colocalization with NOS isoforms can confer selectivity to S-nitrosation. ► Another significant mechanism of selectivity is protein-protein transnitrosation.