title: The inner-mitochondrial distribution of Oxa1 depends on the growth conditions and on the availability of substrates.
abstract: The Oxa1 protein is a well-conserved integral protein of the inner membrane of mitochondria. It mediates the insertion of both mitochondrial- and nuclear-encoded proteins from the matrix into the inner membrane. We investigated the distribution of budding yeast Oxa1 between the two subdomains of the contiguous inner membrane--the cristae membrane (CM) and the inner boundary membrane (IBM)--under different physiological conditions. We found that under fermentable growth conditions, Oxa1 is enriched in the IBM, whereas under nonfermentable (respiratory) growth conditions, it is predominantly localized in the CM. The enrichment of Oxa1 in the CM requires mitochondrial translation; similarly, deletion of the ribosome-binding domain of Oxa1 prevents an enrichment of Oxa1 in the CM. The predominant localization in the IBM under fermentable growth conditions is prevented by inhibiting mitochondrial protein import. Furthermore, overexpression of the nuclear-encoded Oxa1 substrate Mdl1 shifts the distribution of Oxa1 toward the IBM. Apparently, the availability of nuclear- and mitochondrial-encoded substrates influences the inner-membrane distribution of Oxa1. Our findings show that the distribution of Oxa1 within the inner membrane is dynamic and adapts to different physiological needs.
authors.affiliation: Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany. sjakobs@gwdg.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Stoldt
authors.forename: Dirk
authors.initials: D
authors.lastname: Wenzel
authors.forename: Markus
authors.initials: M
authors.lastname: Hildenbeutel
authors.forename: Christian A
authors.initials: CA
authors.lastname: Wurm
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Herrmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Jakobs
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism* / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000097573:Red Fluorescent Protein
chemical_list: D018528:ATP-Binding Cassette Transporters; D002244:Carbon; D003576:Electron Transport Complex IV; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097573:Red Fluorescent Protein; C490069:MDL1 protein, S cerevisiae; C089419:MDM10 protein, S cerevisiae; C090858:OXA1 protein