title: The mitochondrial protein hFis1 regulates mitochondrial fission in mammalian cells through an interaction with the dynamin-like protein DLP1.
abstract: The yeast protein Fis1p has been shown to participate in mitochondrial fission mediated by the dynamin-related protein Dnm1p. In mammalian cells, the dynamin-like protein DLP1/Drp1 functions as a mitochondrial fission protein, but the mechanisms by which DLP1/Drp1 and the mitochondrial membrane interact during the fission process are undefined. In this study, we have tested the role of a mammalian homologue of Fis1p, hFis1, and provided new and mechanistic information about the control of mitochondrial fission in mammalian cells. Through differential tagging and deletion experiments, we demonstrate that the intact C-terminal structure of hFis1 is essential for mitochondrial localization, whereas the N-terminal region of hFis1 is necessary for mitochondrial fission. Remarkably, an increased level of cellular hFis1 strongly promotes mitochondrial fission, resulting in an accumulation of fragmented mitochondria. Conversely, cell microinjection of hFis1 antibodies or treatment with hFis1 antisense oligonucleotides induces an elongated and collapsed mitochondrial morphology. Further, fluorescence resonance energy transfer and coimmunoprecipitation studies demonstrate that hFis1 interacts with DLP1. These results suggest that hFis1 participates in mitochondrial fission through an interaction that recruits DLP1 from the cytosol. We propose that hFis1 is a limiting factor in mitochondrial fission and that the number of hFis1 molecules on the mitochondrial surface determines fission frequency.
authors.affiliation: Center for Basic Research in Digestive Diseases and Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Yisang
authors.initials: Y
authors.lastname: Yoon
authors.forename: Eugene W
authors.initials: EW
authors.lastname: Krueger
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Oswald
authors.forename: Mark A
authors.initials: MA
authors.lastname: McNiven
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D006224:Cricetinae; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D034281:Dynamins; D031541:Fluorescence Resonance Energy Transfer; D019084:Fluorescent Antibody Technique, Indirect; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D017353:Gene Deletion; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism* / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014162:Transfection
chemical_list: C464859:FIS1 protein, S cerevisiae; C476525:FIS1 protein, human; D008164:Luminescent Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D016376:Oligonucleotides, Antisense; D011506:Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate; D004247:DNA; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; D034281:Dynamins