title: When an Intramolecular Disulfide Bridge Governs the Interaction of DUOX2 with Its Partner DUOXA2.
abstract: OBJECTIVE
  The dual oxidase 2 (DUOX2) protein belongs to the NADPH oxidase (NOX) family. As H2O2 generator, it plays a key role in both thyroid hormone biosynthesis and innate immunity. DUOX2 forms with its maturation factor, DUOX activator 2 (DUOXA2), a stable complex at the cell surface that is crucial for the H2O2-generating activity, but the nature of their interaction is unknown. The contribution of some cysteine residues located in the N-terminal ectodomain of DUOX2 in a surface protein-protein interaction is suggested. We have investigated the involvement of different cysteine residues in the formation of covalent bonds that could be of critical importance for the function of the complex.
  
  
  RESULTS
  We report the identification and the characterization of an intramolecular disulfide bond between cys-124 of the N-terminal ectodomain and cys-1162 of an extracellular loop of DUOX2, which has important functional implications in both export and activity of DUOX2. This intramolecular bridge provides structural support for the formation of interdisulfide bridges between the N-terminal domain of DUOX2 and the two extracellular loops of its partner, DUOXA2.
  
  
  METHODS
  Both stability and function of the maturation factor, DUOXA2, are dependent on the oxidative folding of DUOX2, indicating that DUOX2 displays a chaperone-like function with respect to its partner.
  
  
  CONCLUSIONS
  The oxidative folding of DUOX2 that takes place in the endoplasmic reticulum (ER) appears to be a key event in the trafficking of the DUOX2/DUOXA2 complex as it promotes an appropriate conformation of the N-terminal region, which is propitious to subsequent covalent interactions with the maturation factor, DUOXA2.
authors.affiliation: 1 Université Paris-Sud , Orsay, France .|2 UMR 8200 CNRS , Villejuif, France .|3 Institut Gustave Roussy , Villejuif, France .
authors.forename: Aurore
authors.initials: A
authors.lastname: Carré
authors.affiliation: 1 Université Paris-Sud , Orsay, France .|4 Laboratório de Fisiologia Endócrina Doris Rosenthal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Ruy A N
authors.initials: RA
authors.lastname: Louzada
authors.affiliation: 4 Laboratório de Fisiologia Endócrina Doris Rosenthal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Rodrigo S
authors.initials: RS
authors.lastname: Fortunato
authors.affiliation: 1 Université Paris-Sud , Orsay, France .|2 UMR 8200 CNRS , Villejuif, France .|3 Institut Gustave Roussy , Villejuif, France .
authors.forename: Rabii
authors.initials: R
authors.lastname: Ameziane-El-Hassani
authors.affiliation: 5 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Rockville, Maryland.
authors.forename: Stanislas
authors.initials: S
authors.lastname: Morand
authors.affiliation: 6 UMR 8126 CNRS , Villejuif, France .
authors.forename: Vasily
authors.initials: V
authors.lastname: Ogryzko
authors.affiliation: 4 Laboratório de Fisiologia Endócrina Doris Rosenthal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro , Rio de Janeiro, Brazil .
authors.forename: Denise Pires
authors.initials: DP
authors.lastname: de Carvalho
authors.affiliation: 7 Department of Internal Medicine, Division of Gastroenterology, University of Michigan , Ann Arbor, Michigan.
authors.forename: Helmut
authors.initials: H
authors.lastname: Grasberger
authors.affiliation: 5 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Rockville, Maryland.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Leto
authors.affiliation: 1 Université Paris-Sud , Orsay, France .|2 UMR 8200 CNRS , Villejuif, France .|3 Institut Gustave Roussy , Villejuif, France .
authors.forename: Corinne
authors.initials: C
authors.lastname: Dupuy
mesh_terms: D003545:Cysteine / Q000378:metabolism; D004220:Disulfides / Q000378:metabolism*; D000074623:Dual Oxidases; D004721:Endoplasmic Reticulum / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D019255:NADPH Oxidases / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D054730:Protein Interaction Domains and Motifs
chemical_list: C513411:DUOXA2 protein, human; D004220:Disulfides; D008565:Membrane Proteins; D018832:Molecular Chaperones; D000074623:Dual Oxidases; D019255:NADPH Oxidases; C431515:DUOX2 protein, human; D003545:Cysteine