title: Dynamin-like protein 1 is involved in peroxisomal fission.
abstract: The mammalian dynamin-like protein 1 (DLP1), a member of the dynamin family of large GTPases, possesses mechanochemical properties known to constrict and tubulate membranes. In this study, we have combined two experimental approaches, induction of peroxisome proliferation by Pex11pbeta and expression of dominant-negative mutants, to test whether DLP1 plays a role in peroxisomal growth and division. We were able to localize DLP1 in spots on tubular peroxisomes in HepG2 cells. In addition, immunoblot analysis revealed the presence of DLP1 in highly purified peroxisomal fractions from rat liver and an increase of DLP1 after treatment of rats with the peroxisome proliferator bezafibrate. Expression of a dominant negative DLP1 mutant deficient in GTP hydrolysis (K38A) either alone or in combination with Pex11pbeta caused the appearance of tubular peroxisomes but had no influence on their intracellular distribution. In co-expressing cells, the formation of tubulo-reticular networks of peroxisomes was promoted, and peroxisomal division was completely inhibited. These findings were confirmed by silencing of DLP1 using siRNA. We propose a direct role for the dynamin-like protein DLP1 in peroxisomal fission and in the maintenance of peroxisomal morphology in mammalian cells.
authors.affiliation: Department of Cell Biology and Cell Pathology, University of Marburg, Robert Koch Str. 5, Germany.
authors.forename: Annett
authors.initials: A
authors.lastname: Koch
authors.forename: Meinolf
authors.initials: M
authors.lastname: Thiemann
authors.forename: Markus
authors.initials: M
authors.lastname: Grabenbauer
authors.forename: Yisang
authors.initials: Y
authors.lastname: Yoon
authors.forename: Mark A
authors.initials: MA
authors.lastname: McNiven
authors.forename: Michael
authors.initials: M
authors.lastname: Schrader
mesh_terms: D000818:Animals; D002460:Cell Line; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D006801:Humans; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D020675:Peroxisomes / Q000502:physiology*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000502:physiology; D051381:Rats
chemical_list: D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D034741:RNA, Small Interfering; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; C519851:Dnm1l protein, rat; D034281:Dynamins