title: Flavin nucleotides act as electron shuttles mediating reduction of the [2Fe-2S] clusters in mitochondrial outer membrane protein mitoNEET.
abstract: MitoNEET, a primary target of type II diabetes drug pioglitazone, has an essential role in regulating energy metabolism, iron homeostasis, and production of reactive oxygen species in mitochondria. Structurally, mitoNEET is anchored to the mitochondrial outer membrane via its N-terminal transmembrane α-helix. The C-terminal cytosolic domain of mitoNEET hosts a redox active [2Fe-2S] cluster via three cysteine and one histidine residues. Here we report that the reduced flavin nucleotides can rapidly reduce the mitoNEET [2Fe-2S] clusters under anaerobic or aerobic conditions. In the presence of NADH and flavin reductase, 1 molecule of flavin nucleotide is sufficient to reduce about 100 molecules of the mitoNEET [2Fe-2S] clusters in 4min under aerobic conditions. The electron paramagnetic resonance (EPR) measurements show that flavin mononucleotide (FMN), but not flavin adenine dinucleotide (FAD), has a specific interaction with mitoNEET. Molecular docking models further reveal that flavin mononucleotide binds mitoNEET at the region between the N-terminal transmembrane α-helix and the [2Fe-2S] cluster binding domain. The closest distance between the [2Fe-2S] cluster and the bound flavin mononucleotide in mitoNEET is about 10Å, which could facilitate rapid electron transfer from the reduced flavin nucleotide to the [2Fe-2S] cluster in mitoNEET. The results suggest that flavin nucleotides may act as electron shuttles to reduce the mitoNEET [2Fe-2S] clusters and regulate mitochondrial functions in human cells.
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Landry
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Zishuo
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Crochet
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA. Electronic address: hding@lsu.edu.
authors.forename: Huangen
authors.initials: H
authors.lastname: Ding
mesh_terms: D003545:Cysteine / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D004138:Dinitrocresols / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000378:metabolism*; D062105:Molecular Docking Simulation; D009243:NAD / Q000378:metabolism; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D000077205:Pioglitazone; D011485:Protein Binding; D017382:Reactive Oxygen Species / Q000378:metabolism; D045162:Thiazolidinediones / Q000627:therapeutic use
chemical_list: C525595:CISD1 protein, human; D004138:Dinitrocresols; D007506:Iron-Sulfur Proteins; D024101:Mitochondrial Proteins; D009711:Nucleotides; D017382:Reactive Oxygen Species; D045162:Thiazolidinediones; D009243:NAD; C024132:4,6-dinitro-o-cresol; D007501:Iron; D010088:Oxidoreductases; D003545:Cysteine; D000077205:Pioglitazone
keywords: Flavin nucleotides; Iron-sulfur cluster; Redox regulation; Type II diabetes; mitoNEET