title: Existence of catalase-less peroxisomes in Sf21 insect cells.
abstract: Catalase activity, a peroxisomal marker enzyme, was not detectable in any of the subcellular fractions of Spodoptera frugiperda (Sf) 21 insect cells, although marker enzymes in other organelles were distributed in the fractions in a manner similar to that seen in mammalian cells. When a green fluorescent protein fused with peroxisome targeting signal 1 at the C-terminal (GFP-SKL) was expressed in Sf21 cells, punctate fluorescent dots were observed in the cytoplasm. The fraction where GFP-SKL was concentrated exhibited long-chain and very-long-chain fatty acid beta-oxidation activities in the presence of KCN and the density of this fraction was slightly higher than that of mitochondria. Immunoelectron microscopy studies with anti-SKL antibody demonstrated that Sf21 cells have immunoreactive peroxisome-like organelles which are structurally distinct from mitochondria, endoplasmic reticulum, and lysosomes. In contrast to peroxisomal matrix proteins, adrenoleukodystrophy protein, a peroxisomal membrane protein, was not located to peroxisomes. This suggests that the targeting signal for PMP in insect cells is distinct from that in mammalian cells. These results demonstrate that Sf21 insect cells have unique catalase-less peroxisomes capable of beta-oxidation of fatty acids.
authors.affiliation: Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, 930-0194, Toyama, Japan.
authors.forename: Mikinori
authors.initials: M
authors.lastname: Kurisu
authors.forename: Masashi
authors.initials: M
authors.lastname: Morita
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kashiwayama
authors.forename: Sadaki
authors.initials: S
authors.lastname: Yokota
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hayashi
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Sakai
authors.forename: Shoji
authors.initials: S
authors.lastname: Ohkuma
authors.forename: Mikio
authors.initials: M
authors.lastname: Nishimura
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Imanaka
mesh_terms: D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002374:Catalase / Q000378:metabolism*; D002460:Cell Line; D004274:DNA, Recombinant / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D010084:Oxidation-Reduction; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism* / Q000648:ultrastructure; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018411:Spodoptera; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C115572:ABCD1 protein, human; D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters; D004274:DNA, Recombinant; D005227:Fatty Acids; D008164:Luminescent Proteins; D000074435:Peroxisome-Targeting Signal 1 Receptor; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002374:Catalase