Hidden networks of aberrant protein transnitrosylation contribute to synapse loss in Alzheimer's disease.

Emerging evidence indicates the importance of S-nitrosation in regulating protein function and activity. This chemical reaction has been termed protein S-nitrosylation to emphasize its biological importance as a posttranslational modification, in some ways reminiscent of phosphorylation. The reaction at cysteine thiols is distinct from other chemical reactions of nitric oxide (NO) that activate soluble guanylate cyclase via nitrosylation of heme or formation of peroxynitrite via reaction with superoxide anion to produce tyrosine nitration. Here, we review the importance of pathological, aberrant transnitrosylation reactions, i.e., transfer of the NO group from one protein to another, and its consequent effect on the pathogenesis of neurological disorders, to date on Alzheimer's disease (AD), but also expected to affect Parkinson's disease (PD)/Lewy body dementia (LBD), HIV-associated neurocognitive disorder (HAND), and other neurodegenerative and neurodevelopmental disorders.