title: The insulin-like growth factor-I-mTOR signaling pathway induces the mitochondrial pyrimidine nucleotide carrier to promote cell growth.
abstract: The insulin/insulin-like growth factor (IGF) signaling pathway to mTOR is essential for the survival and growth of normal cells and also contributes to the genesis and progression of cancer. This signaling pathway is linked with regulation of mitochondrial function, but how is incompletely understood. Here we show that IGF-I and insulin induce rapid transcription of the mitochondrial pyrimidine nucleotide carrier PNC1, which shares significant identity with the essential yeast mitochondrial carrier Rim2p. PNC1 expression is dependent on PI-3 kinase and mTOR activity and is higher in transformed fibroblasts, cancer cell lines, and primary prostate cancers than in normal tissues. Overexpression of PNC1 enhances cell size, whereas suppression of PNC1 expression causes reduced cell size and retarded cell cycle progression and proliferation. Cells with reduced PNC1 expression have reduced mitochondrial UTP levels, but while mitochondrial membrane potential and cellular ATP are not altered, cellular ROS levels are increased. Overall the data indicate that PNC1 is a target of the IGF-I/mTOR pathway that is essential for mitochondrial activity in regulating cell growth and proliferation.
authors.affiliation: Cell Biology Laboratory, Department of Biochemistry, BioSciences Institute, National University of Ireland, Cork, Ireland.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Floyd
authors.forename: Cedric
authors.initials: C
authors.lastname: Favre
authors.forename: Francesco M
authors.initials: FM
authors.lastname: Lasorsa
authors.forename: Madeline
authors.initials: M
authors.lastname: Leahy
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Trigiante
authors.forename: Philipp
authors.initials: P
authors.lastname: Stroebel
authors.forename: Alexander
authors.initials: A
authors.lastname: Marx
authors.forename: Gary
authors.initials: G
authors.lastname: Loughran
authors.forename: Katie
authors.initials: K
authors.lastname: O'Callaghan
authors.forename: Carlo M T
authors.initials: CM
authors.lastname: Marobbio
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Slotboom
authors.forename: Edmund R S
authors.initials: ER
authors.lastname: Kunji
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Palmieri
authors.forename: Rosemary
authors.initials: R
authors.lastname: O'Connor
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D033704:Nucleotide Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D058570:TOR Serine-Threonine Kinases; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: D007328:Insulin; D024101:Mitochondrial Proteins; D033704:Nucleotide Transport Proteins; C524123:PNC1 protein, mouse; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D007334:Insulin-Like Growth Factor I; D011494:Protein Kinases; C546842:MTOR protein, human; C546843:mTOR protein, mouse; D017526:Receptor, IGF Type 1; D058570:TOR Serine-Threonine Kinases; D014544:Uridine Triphosphate