title: YajL, prokaryotic homolog of parkinsonism-associated protein DJ-1, functions as a covalent chaperone for thiol proteome.
abstract: YajL is the closest Escherichia coli homolog of the Parkinsonism-associated protein DJ-1, a multifunctional oxidative stress response protein whose biochemical function remains unclear. We recently reported the aggregation of proteins in a yajL mutant in an oxidative stress-dependent manner and that YajL exhibits chaperone activity. Here, we show that YajL displays covalent chaperone and weak protein oxidoreductase activities that are dependent on its exposed cysteine 106. It catalyzes reduced RNase oxidation and scrambled RNase isomerization and insulin reduction and forms mixed disulfides with many cellular proteins upon oxidative stress. The formation of mixed disulfides was detected by immunoblotting bacterial extracts with anti-YajL antibodies under nonreducing conditions. Disulfides were purified from bacterial extracts on a YajL affinity column, separated by nonreducing-reducing SDS-PAGE, and identified by mass spectrometry. Covalent YajL substrates included ribosomal proteins, aminoacyl-tRNA synthetases, chaperones, catalases, peroxidases, and other proteins containing cysteines essential for catalysis or FeS cluster binding, such as glyceraldehyde-3-phosphate dehydrogenase, aldehyde dehydrogenase, aconitase, and FeS cluster-containing subunits of respiratory chains. In addition, we show that DJ-1 also forms mixed disulfides with cytoplasmic proteins upon oxidative stress. These results shed light on the oxidative stress-dependent chaperone function of YajL and identify YajL substrates involved in translation, stress protection, protein solubilization, and metabolism. They reveal a crucial role for cysteine 106 and suggest that DJ-1 also functions as a covalent chaperone. These findings are consistent with several defects observed in yajL or DJ-1 mutants, including translational defects, protein aggregation, oxidative stress sensitivity, and metabolic deficiencies.
authors.affiliation: Stress Molecules Group, Institut Jacques Monod, Université Paris 7/CNRS, 15 rue Hélène Brion, 75013 Paris, France.
authors.forename: Hai-Tuong
authors.initials: HT
authors.lastname: Le
authors.forename: Valérie
authors.initials: V
authors.lastname: Gautier
authors.forename: Fatoum
authors.initials: F
authors.lastname: Kthiri
authors.forename: Abderrahim
authors.initials: A
authors.lastname: Malki
authors.forename: Nadia
authors.initials: N
authors.lastname: Messaoudi
authors.forename: Mouadh
authors.initials: M
authors.lastname: Mihoub
authors.forename: Ahmed
authors.initials: A
authors.lastname: Landoulsi
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: An
authors.forename: Sun-Shin
authors.initials: SS
authors.lastname: Cha
authors.forename: Gilbert
authors.initials: G
authors.lastname: Richarme
mesh_terms: D004220:Disulfides / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D015513:Oncogene Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism; D000071617:Protein Deglycase DJ-1; D019704:Protein Disulfide-Isomerases / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D004220:Disulfides; D029968:Escherichia coli Proteins; D047908:Intracellular Signaling Peptides and Proteins; D018832:Molecular Chaperones; D015513:Oncogene Proteins; D020543:Proteome; D012269:Ribosomal Proteins; D013438:Sulfhydryl Compounds; C554198:YajL protein, E coli; D010088:Oxidoreductases; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1; D019704:Protein Disulfide-Isomerases