title: ATP Binding and Hydrolysis Properties of ABCB10 and Their Regulation by Glutathione.
abstract: ABCB10 (ATP binding cassette sub-family B10) is a mitochondrial inner-membrane ABC transporter. ABCB10 has been shown to protect the heart from the impact of ROS during ischemia-reperfusion and to allow for proper hemoglobin synthesis during erythroid development. ABC transporters are proteins that increase ATP binding and hydrolysis activity in the presence of the transported substrate. However, molecular entities transported by ABCB10 and its regulatory mechanisms are currently unknown. Here we characterized ATP binding and hydrolysis properties of ABCB10 by using the 8-azido-ATP photolabeling technique. This technique can identify potential ABCB10 regulators, transported substrates and amino-acidic residues required for ATP binding and hydrolysis. We confirmed that Gly497 and Lys498 in the Walker A motif, Glu624 in the Walker B motif and Gly602 in the C-Loop motif of ABCB10 are required for proper ATP binding and hydrolysis activity, as their mutation changed ABCB10 8-Azido-ATP photo-labeling. In addition, we show that the potential ABCB10 transported entity and heme precursor delta-aminolevulinic acid (dALA) does not alter 8-azido-ATP photo-labeling. In contrast, oxidized glutathione (GSSG) stimulates ATP hydrolysis without affecting ATP binding, whereas reduced glutathione (GSH) inhibits ATP binding and hydrolysis. Indeed, we detectABCB10 glutathionylation in Cys547 and show that it is one of the exposed cysteine residues within ABCB10 structure. In all, we characterize essential residues for ABCB10 ATPase activity and we provide evidence that supports the exclusion of dALA as a potential substrate directly transported by ABCB10. Last, we show the first molecular mechanism by which mitochondrial oxidative status, through GSH/GSSG, can regulate ABCB10.
authors.affiliation: Department of Medicine, Obesity and Nutrition Section, Mitochondria ARC, Evans Biomedical Research Center, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Wei
authors.initials: W
authors.lastname: Qiu
authors.affiliation: Department of Medicine, Obesity and Nutrition Section, Mitochondria ARC, Evans Biomedical Research Center, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Marc
authors.initials: M
authors.lastname: Liesa
authors.affiliation: Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Elizabeth P
authors.initials: EP
authors.lastname: Carpenter
authors.affiliation: Department of Medicine, Obesity and Nutrition Section, Mitochondria ARC, Evans Biomedical Research Center, Boston University School of Medicine, Boston, Massachusetts, United States of America; Department of Clinical Biochemistry, School of Medicine, Ben Gurion University, Beer-Sheva, Israel.
authors.forename: Orian S
authors.initials: OS
authors.lastname: Shirihai
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism*; D000622:Aminolevulinic Acid / Q000378:metabolism; D000818:Animals; D001386:Azides / Q000378:metabolism; D001710:Biotin / Q000378:metabolism; D017124:Conserved Sequence; D003545:Cysteine / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D006868:Hydrolysis; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D013367:Submitochondrial Particles / Q000187:drug effects / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; C410734:Abcb10 protein, mouse; D001386:Azides; C017040:8-azidoadenosine 5'-triphosphate; D001710:Biotin; D000622:Aminolevulinic Acid; D000255:Adenosine Triphosphate; D005978:Glutathione; D003545:Cysteine; D019803:Glutathione Disulfide