Assessment and application of the biotin switch technique for examining protein S-nitrosylation under conditions of pharmacologically induced oxidative stress.

Published

Journal Article

Protein S-nitrosylation has emerged as a principal mechanism by which nitric oxide exerts biological effects. Among methods for studying protein S-nitrosylation, the biotin switch technique (BST) has rapidly gained popularity because of the ease with which it can detect individual S-nitrosylated (SNO) proteins in biological samples. The identification of SNO sites by the BST relies on the ability of ascorbate to generate a thiol from an S-nitrosothiol, but not from alternatively S-oxidized thiols (e.g. disulfides, sulfenic acids). However, the specificity of this reaction has recently been challenged, prompting several claims that the BST may produce false-positive results and raising concerns about the application of the BST under oxidizing conditions. Here we perform a comparative analysis of the BST using differentially S-oxidized and S-nitrosylated forms of protein tyrosine phosphatase 1B, as well as intact and lysed human embryonic kidney 293 cells treated with S-oxidizing and S-nitrosylating agents, and verify that the assay is highly specific for SNO. Strikingly, exposure of samples to indirect sunlight from a laboratory window resulted in artifactual ascorbate-dependent signals that are likely promoted by the semidehydroascorbate radical; protection from sunlight eliminated the artifact. In contrast, exposure of SNO proteins to a strong ultraviolet light source (SNO photolysis) prior to the BST provided independent verification of assay specificity. By combining BST with photolysis, we have shown that anti-cancer drug-induced oxidative stress facilitates the S-nitrosylation of the major apoptotic effector glyceraldehyde-3-phosphate dehydrogenase. Collectively, these experiments demonstrate that SNO-dependent signaling pathways can be modulated by oxidative conditions and suggest a potential role for S-nitrosylation in antineoplastic drug action.

Full Text

Duke Authors

Cited Authors

  • Forrester, MT; Foster, MW; Stamler, JS

Published Date

  • May 11, 2007

Published In

Volume / Issue

  • 282 / 19

Start / End Page

  • 13977 - 13983

PubMed ID

  • 17376775

Pubmed Central ID

  • 17376775

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M609684200

Language

  • eng

Conference Location

  • United States