title: Novel regulatory roles of Mff and Drp1 in E3 ubiquitin ligase MARCH5-dependent degradation of MiD49 and Mcl1 and control of mitochondrial dynamics.
abstract: MARCH5, an OMM-associated E3 ubiquitin ligase, controls mitochondrial function. Despite its importance, the mechanism and factors controlling MARCH5 activity are largely unknown. Here we report that the MARCH5 C-terminal domain plays a critical role in degradation of MARCH5 substrates, likely by facilitating release of ubiquitinated proteins from the OMM. We also found that the mitochondrial fission proteins Drp1 and Mff negatively regulate MARCH5's activity toward MiD49 and Mcl1. Knockouts of either Drp1 or Mff led to reduced expression, shorter half-lives, and increased ubiquitination of MiD49 and Mcl1. Effects of Mff and Drp1 depletion on degradation rates and ubiquitination of Mcl1 and MiD49 were eliminated in Drp1-/-/MARCH5-/-and Mff-/-/MARCH5-/-cells. Our data show that it is not mitochondrial morphology per se but rather Mff and Drp1 that directly control MARCH5. Consistently, we find that Mff is an integral component of the MARCH5/p97/Npl4 complex, which is also controlled by MARCH5's C-terminal domain. Furthermore, not only mitochondrial fission but also fusion is regulated through Mff and Drp1 protein activities. Thus, in addition to their canonical roles in mitochondrial fission, Mff and Drp1 also act as regulatory factors that control mitochondrial fission and fusion.
authors.affiliation: Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Edward
authors.initials: E
authors.lastname: Cherok
authors.affiliation: Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Shan
authors.initials: S
authors.lastname: Xu
authors.affiliation: Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Sunan
authors.initials: S
authors.lastname: Li
authors.affiliation: Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Shweta
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: W Alex
authors.initials: WA
authors.lastname: Meltzer
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Michal
authors.initials: M
authors.lastname: Zalzman
authors.affiliation: Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Chunxin
authors.initials: C
authors.lastname: Wang
authors.affiliation: Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.|Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Karbowski
mesh_terms: D018929:Cell Culture Techniques; D034281:Dynamins; D020558:GTP Phosphohydrolases / Q000378:metabolism / Q000502:physiology; D045325:HCT116 Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism; D063154:Mitochondrial Dynamics / Q000235:genetics / Q000502:physiology*; D051336:Mitochondrial Membranes / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism / Q000502:physiology; D010445:Peptide Elongation Factors / Q000378:metabolism / Q000502:physiology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D054875:Ubiquitination
chemical_list: C585230:MIEF2 protein, human; D008565:Membrane Proteins; C533267:Mff protein, human; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D010445:Peptide Elongation Factors; C515578:MARCHF5 protein, human; D044767:Ubiquitin-Protein Ligases; D020558:GTP Phosphohydrolases; C110768:DNM1L protein, human; D034281:Dynamins