title: Increased mitochondrial thioredoxin 2 potentiates N-ethylmaleimide-induced cytotoxicity.
abstract: Thioredoxin 2 (Trx2) is a mitochondrially localized antioxidant and antiapoptotic protein, whose functions are mainly dependent on the conserved cysteines at its redox active center. In the current study, we showed by mass spectrometry that a thiol alkylating agent, N-ethylmaleimide (NEM), alkylated a single cysteine residue in the active center of Trx2. The interaction between NEM and Trx2 in intact cells was confirmed by redox Western analysis. Overexpression of Trx2 in cultured 143B osteosarcoma cells caused increased sensitivity to NEM. Covalent modification by NEM resulted in a dominant-negative effect and increased the interaction between Trx2 and peroxiredoxin 3 (Prx3). Our data suggest that the alkylation of the essential thiol(s) of Trx2 has profound impact on the mitochondrial redox circuitry and that such effects are distinct from the responses to agents causing reversible disulfide bond formation between the vicinal dithiols in the active center.
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Go
authors.forename: Jan
authors.initials: J
authors.lastname: Pohl
authors.forename: Matthew
authors.initials: M
authors.lastname: Reed
authors.forename: Jiyang
authors.initials: J
authors.lastname: Cai
authors.forename: Dean P
authors.initials: DP
authors.lastname: Jones
mesh_terms: D045744:Cell Line, Tumor; D005033:Ethylmaleimide / Q000633:toxicity*; D005786:Gene Expression Regulation; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D009154:Mutation / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D013879:Thioredoxins; D005033:Ethylmaleimide