title: Mutants of the Yarrowia lipolytica PEX23 gene encoding an integral peroxisomal membrane peroxin mislocalize matrix proteins and accumulate vesicles containing peroxisomal matrix and membrane proteins.
abstract: pex mutants are defective in peroxisome assembly. The mutant strain pex23-1 of the yeast Yarrowia lipolytica lacks morphologically recognizable peroxisomes and mislocalizes all peroxisomal matrix proteins investigated preferentially to the cytosol. pex23 strains accumulate vesicular structures containing both peroxisomal matrix and membrane proteins. The PEX23 gene was isolated by functional complementation of the pex23-1 strain and encodes a protein, Pex23p, of 418 amino acids (47,588 Da). Pex23p exhibits high sequence similarity to two hypothetical proteins of the yeast Saccharomyces cerevisiae. Pex23p is an integral membrane protein of peroxisomes that is completely, or nearly completely, sequestered from the cytosol. Pex23p is detected at low levels in cells grown in medium containing glucose, and its levels are significantly increased by growth in medium containing oleic acid, the metabolism of which requires intact peroxisomes.
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
authors.forename: T W
authors.initials: TW
authors.lastname: Brown
authors.forename: V I
authors.initials: VI
authors.lastname: Titorenko
authors.forename: R A
authors.initials: RA
authors.lastname: Rachubinski
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003470:Culture Media; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics*; D005800:Genes, Fungal; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019301:Oleic Acid; D020675:Peroxisomes / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D004718:Saccharomycetales / Q000235:genetics* / Q000254:growth & development; D017386:Sequence Homology, Amino Acid
chemical_list: D003470:Culture Media; D018076:DNA, Complementary; D005656:Fungal Proteins; D008565:Membrane Proteins; C405990:PEX23 protein, Yarrowia lipolytica; D016271:Proto-Oncogene Proteins c-myc; D019301:Oleic Acid