title: A Fox2-dependent fatty acid ß-oxidation pathway coexists both in peroxisomes and mitochondria of the ascomycete yeast Candida lusitaniae.
abstract: It is generally admitted that the ascomycete yeasts of the subphylum Saccharomycotina possess a single fatty acid ß-oxidation pathway located exclusively in peroxisomes, and that they lost mitochondrial ß-oxidation early during evolution. In this work, we showed that mutants of the opportunistic pathogenic yeast Candida lusitaniae which lack the multifunctional enzyme Fox2p, a key enzyme of the ß-oxidation pathway, were still able to grow on fatty acids as the sole carbon source, suggesting that C. lusitaniae harbored an alternative pathway for fatty acid catabolism. By assaying 14Cα-palmitoyl-CoA consumption, we demonstrated that fatty acid catabolism takes place in both peroxisomal and mitochondrial subcellular fractions. We then observed that a fox2Δ null mutant was unable to catabolize fatty acids in the mitochondrial fraction, thus indicating that the mitochondrial pathway was Fox2p-dependent. This finding was confirmed by the immunodetection of Fox2p in protein extracts obtained from purified peroxisomal and mitochondrial fractions. Finally, immunoelectron microscopy provided evidence that Fox2p was localized in both peroxisomes and mitochondria. This work constitutes the first demonstration of the existence of a Fox2p-dependent mitochondrial β-oxidation pathway in an ascomycetous yeast, C. lusitaniae. It also points to the existence of an alternative fatty acid catabolism pathway, probably located in peroxisomes, and functioning in a Fox2p-independent manner.
authors.affiliation: Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gabriel
authors.affiliation: Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Accoceberry
authors.affiliation: Univ. Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33000 Bordeaux, France; CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33000 Bordeaux, France.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Bessoule
authors.affiliation: Univ. Bordeaux, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France; CNRS, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Salin
authors.affiliation: Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Lucas-Guérin
authors.affiliation: Univ. Bordeaux, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France; CNRS, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France.
authors.forename: Stephen
authors.initials: S
authors.lastname: Manon
authors.affiliation: Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Dementhon
authors.affiliation: Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Noël
mesh_terms: D015153:Blotting, Western; D002175:Candida / Q000254:growth & development / Q000378:metabolism*; D002177:Candidiasis / Q000378:metabolism / Q000382:microbiology; D002244:Carbon / Q000378:metabolism; D002478:Cells, Cultured; D004746:Enoyl-CoA Hydratase / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry* / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D020675:Peroxisomes / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D005227:Fatty Acids; D012333:RNA, Messenger; D002244:Carbon; D004746:Enoyl-CoA Hydratase