Biological Functions and Importance of Protein S-Nitrosation

S-Nitrosation is a new type of protein posttranslational modification. S-nitrosothiols, which are stable and mobile reservoirs of nitric oxide, are considered convergence points of signalling pathways of reactive oxygen and nitrogen species. This review summarizes the current knowledge of the origin, properties and biological functions of both low-molecular-weight and protein S-nitrosothiols. The biological functions of the former nitrosothiols are derived from their ability to decompose yielding NO or to trans-nitrosate protein thiols. Altered levels of the S-nitrosothiols and S-nitrosation of proteins are associated with nitrosation stress, resulting in a series of pathological processes. Although considerable advances in the research on S-nitrosothiols and protein S-nitrosation have been recently achieved, understanding the exact role and functions of S-nitrosation in signalling pathways of reactive nitrogen species is still very limited.