title: Peroxisomes are formed from complex membrane structures in PEX6-deficient CHO cells upon genetic complementation.
abstract: Pex6p belongs to the AAA family of ATPases. Its CHO mutant, ZP92, lacks normal peroxisomes but contains peroxisomal membrane remnants, so called peroxisomal ghosts, which are detected with anti-70-kDa peroxisomal membrane protein (PMP70) antibody. No peroxisomal matrix proteins were detected inside the ghosts, but exogenously expressed green fluorescent protein (GFP) fused to peroxisome targeting signal-1 (PTS-1) accumulated in the areas adjacent to the ghosts. Electron microscopic examination revealed that PMP70-positive ghosts in ZP92 were complex membrane structures, rather than peroxisomes with reduced matrix protein import ability. In a typical case, a set of one central spherical body and two layers of double-membraned loops were observed, with endoplasmic reticulum present alongside the outer loop. In the early stage of complementation by PEX6 cDNA, catalase and acyl-CoA oxidase accumulated in the lumen of the double-membraned loops. Biochemical analysis revealed that almost all the peroxisomal ghosts were converted into peroxisomes upon complementation. Our results indicate that 1) Peroxisomal ghosts are complex membrane structures; and 2) The complex membrane structures become import competent and are converted into peroxisomes upon complementation with PEX6.
authors.affiliation: Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Hyogo 678-1297, Japan.
authors.forename: Noriyo
authors.initials: N
authors.lastname: Hashiguchi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kojidani
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Imanaka
authors.forename: Tokuko
authors.initials: T
authors.lastname: Haraguchi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hiraoka
authors.forename: Eveline
authors.initials: E
authors.lastname: Baumgart
authors.forename: Sadaki
authors.initials: S
authors.lastname: Yokota
authors.forename: Toshiro
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Osumi
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000172:deficiency / Q000235:genetics*; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D005347:Fibroblasts / Q000502:physiology / Q000648:ultrastructure; D005816:Genetic Complementation Test; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology; D020675:Peroxisomes / Q000502:physiology* / Q000648:ultrastructure
chemical_list: C063305:ABCD3 protein, human; D018528:ATP-Binding Cassette Transporters; C489272:Abcd3 protein, rat; D008565:Membrane Proteins; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C490759:PEX6 protein, human; C096998:Pex6 protein, rat