title: Enlarged peroxisomes are present in oleic acid-grown Yarrowia lipolytica overexpressing the PEX16 gene encoding an intraperoxisomal peripheral membrane peroxin.
abstract: Pex mutants of the yeast Yarrowia lipolytica are defective in peroxisome assembly. The mutant strain pex16-1 lacks morphologically recognizable peroxisomes. Most peroxisomal proteins are mislocalized to a subcellular fraction enriched for cytosol in pex16 strains, but a subset of peroxisomal proteins is localized at, or near, wild-type levels to a fraction typically enriched for peroxisomes. The PEX16 gene was isolated by functional complementation of the pex16-1 strain and encodes a protein, Pex16p, of 391 amino acids (44,479 D). Pex16p has no known homologues. Pex16p is a peripheral protein located at the matrix face of the peroxisomal membrane. Substitution of the carboxylterminal tripeptide Ser-Thr-Leu, which is similar to the consensus sequence of peroxisomal targeting signal 1, does not affect targeting of Pex16p to peroxisomes. Pex16p is synthesized in wild-type cells grown in glucose-containing media, and its levels are modestly increased by growth of cells in oleic acid-containing medium. Overexpression of the PEX16 gene in oleic acid- grown Y. lipolytica leads to the appearance of a small number of enlarged peroxisomes, which contain the normal complement of peroxisomal proteins at levels approaching those of wild-type peroxisomes.
authors.affiliation: Department of Cell Biology and Anatomy, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
authors.forename: G A
authors.initials: GA
authors.lastname: Eitzen
authors.forename: R K
authors.initials: RK
authors.lastname: Szilard
authors.forename: R A
authors.initials: RA
authors.lastname: Rachubinski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002264:Carboxylic Acids; D004271:DNA, Fungal; D005109:Extracellular Matrix / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D006168:Guinea Pigs; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008830:Microbodies; D008969:Molecular Sequence Data; D019301:Oleic Acid / Q000494:pharmacology; D011817:Rabbits; D004718:Saccharomycetales / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D015003:Yeasts / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D002264:Carboxylic Acids; D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D019301:Oleic Acid