title: S-nitrosylation of thioredoxin mediates activation of apoptosis signal-regulating kinase 1.
abstract: Apoptosis signal-regulating kinase 1 (ASK1) was recently discovered as a typical member of the mitogen-activated protein (MAP) kinase kinase kinase family, which induces apoptosis by activation of c-Jun-N-terminal kinase/p38 MAP kinase pathways. In normal cells ASK1 is directly inhibited by thioredoxin (Trx), a 12-kDa protein ubiquitously expressed in all living cells, which has a variety of biological functions related to cell proliferation and apoptosis. Here we found that purified Trx is sensitive to S-nitrosylation. Stimulation of HEK-293 cells with S-nitrosoglutathione (GSNO) for 2, 4, 8, and 16h also caused Trx S-nitrosylation, which showed straight correlation with ASK1 activation based on Western blot detection of the enzyme, immunoprecipitation assay, and measurement of its catalytic activity. These results suggest that S-nitrosylation of Trx induces ASK1 activation. Treatment of cells with N-acetyl-cysteine for 2h after 8h of pretreatment with GSNO caused an increase in glutathione and nullified ASK1 activation.
authors.affiliation: Department of Biochemistry, Mechnikov Odessa National University, Apt. 208, Glushko Prospect 16, Odessa 65104, Ukraine. sumbayev@yahoo.co.uk
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Sumbayev
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D003124:Colorimetry; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases / Q000096:biosynthesis* / Q000737:chemistry*; D015538:Nitrosation; D026422:S-Nitrosoglutathione / Q000737:chemistry* / Q000494:pharmacology; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism; D013879:Thioredoxins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D013879:Thioredoxins; D026422:S-Nitrosoglutathione; D013455:Sulfur; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases; C482858:MAP3K5 protein, human