title: CBP80 promotes interaction of Upf1 with Upf2 during nonsense-mediated mRNA decay in mammalian cells.
abstract: In mammalian cells, nonsense-mediated messenger RNA decay (NMD) targets newly synthesized nonsense-containing mRNA bound by the cap-binding-protein heterodimer CBP80-CBP20 and at least one exon-junction complex (EJC). An EJC includes the NMD factors Upf3 or Upf3X and Upf2, and Upf2 recruits Upf1. Once this pioneer translation initiation complex is remodeled so that CBP80-CBP20 is replaced by eukaryotic initiation factor 4E, the mRNA is no longer detectably targeted for NMD. Here, we provide evidence that CBP80 augments the efficiency of NMD but not of Staufen1 (Stau1)-mediated mRNA decay (SMD). SMD depends on the recruitment of Upf1 by the RNA-binding protein Stau1 but does not depend on the other Upf proteins. We find that CBP80 interacts with Upf1 and promotes the interaction of Upf1 with Upf2 but not with Stau1.
authors.affiliation: Department of Biochemistry and Biophysics, School of Medicine and Dentistry, 601 Elmwood Avenue, Box 712, University of Rochester, Rochester, New York 14642, USA.
authors.forename: Nao
authors.initials: N
authors.lastname: Hosoda
authors.forename: Yoon Ki
authors.initials: YK
authors.lastname: Kim
authors.forename: Fabrice
authors.initials: F
authors.lastname: Lejeune
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Maquat
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D018389:Codon, Nonsense; D003598:Cytoskeletal Proteins; D015536:Down-Regulation; D006367:HeLa Cells; D006801:Humans; D039502:Nuclear Cap-Binding Protein Complex / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D020365:RNA Helicases; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D018389:Codon, Nonsense; D003598:Cytoskeletal Proteins; C087000:EIF4EBP1 protein, human; D039502:Nuclear Cap-Binding Protein Complex; D010750:Phosphoproteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; C492185:STAU1 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; C468286:UPF2 protein, human; D020365:RNA Helicases; C101828:UPF1 protein, human