title: MitoTimer probe reveals the impact of autophagy, fusion, and motility on subcellular distribution of young and old mitochondrial protein and on relative mitochondrial protein age.
abstract: To study mitochondrial protein age dynamics, we targeted a time-sensitive fluorescent protein, MitoTimer, to the mitochondrial matrix. Mitochondrial age was revealed by the integrated portions of young (green) and old (red) MitoTimer protein. Mitochondrial protein age was dependent on turnover rates as pulsed synthesis, decreased import, or autophagic inhibition all increased the proportion of aged MitoTimer protein. Mitochondrial fusion promotes the distribution of young mitochondrial protein across the mitochondrial network as cells lacking essential fusion genes Mfn1 and Mfn2 displayed increased heterogeneity in mitochondrial protein age. Experiments in hippocampal neurons illustrate that the distribution of older and younger mitochondrial protein within the cell is determined by subcellular spatial organization and compartmentalization of mitochondria into neurites and soma. This effect was altered by overexpression of mitochondrial transport protein, RHOT1/MIRO1. Collectively our data show that distribution of young and old protein in the mitochondrial network is dependent on turnover, fusion, and transport.
authors.affiliation: Department of Medicine, Obesity and Nutrition Section; The Mitochondria Affinity Research Collaborative; Evans Biomedical Research Center; Boston University School of Medicine; Boston, MA USA.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Ferree
authors.forename: Kyle
authors.initials: K
authors.lastname: Trudeau
authors.forename: Eden
authors.initials: E
authors.lastname: Zik
authors.forename: Ilan Y
authors.initials: IY
authors.lastname: Benador
authors.forename: Gilad
authors.initials: G
authors.lastname: Twig
authors.forename: Roberta A
authors.initials: RA
authors.lastname: Gottlieb
authors.forename: Orian S
authors.initials: OS
authors.lastname: Shirihai
mesh_terms: D000818:Animals; D001343:Autophagy; D006624:Hippocampus / Q000378:metabolism; D007700:Kinetics; D008164:Luminescent Proteins / Q000378:metabolism*; D051379:Mice; D063154:Mitochondrial Dynamics; D024101:Mitochondrial Proteins / Q000096:biosynthesis / Q000378:metabolism*; D008954:Models, Biological; D015335:Molecular Probes / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D000097573:Red Fluorescent Protein
chemical_list: D008164:Luminescent Proteins; D024101:Mitochondrial Proteins; D015335:Molecular Probes; D000097573:Red Fluorescent Protein
keywords: MitoTimer; RHOT1; aging; autophagy; mitochondrial dynamics