Cell Biology

Regulating S-Nitrosylation

Science Signaling  27 May 2008:
Vol. 1, Issue 21, pp. ec202
DOI: 10.1126/stke.121ec202

Covalent modification of proteins by S-nitrosylation is an important mechanism for regulation of biochemical activity in cells. However, mechanisms of protein denitrosylation have not been well characterized. The protease caspase-3, which promotes apoptosis, is inhibited by S-nitrosylation and is denitrosylated in cells in which the cell death-promoting receptor Fas is activated. Benhar et al. (see the Perspective by Holmgren) purified a protein fraction that catalyzed denitrosylation of caspase-3 and identified thioredoxin-1 (Trx1) as the protein most likely to be responsible for the denitrosylation activity. Depletion of Trx1 caused accumulation of S-nitrosylated caspase-3 and other S-nitrosylated proteins in cultured cells, and Fas-induced denitrosylation of caspase-3 was inhibited by depleting thioredoxin reductase 2. Thus, regulated denitrosylation of target proteins by Trx1 appears to provide a key component of enzymatic regulation of caspase-3 and possibly other proteins by S-nitrosylation.

M. Benhar, M. T. Forrester, D. T. Hess, J. S. Stamler, Regulated protein denitrosylation by cytosolic and mitochondrial thioredoxins. Science 320, 1050-1054 (2008). [Abstract] [Full Text]

A. Holmgren, SNO Removal. Science 320, 1019-1020 (2008). [Summary] [Full Text]