title: Y14 and hUpf3b form an NMD-activating complex.
abstract: Messenger RNAs with premature translation termination codons (PTCs) are degraded by nonsense-mediated mRNA decay (NMD). In mammals, PTCs are discriminated from physiological stop codons by a process thought to involve the splicing-dependent deposition of an exon junction complex (EJC), EJC-mediated recruitment of Upf3, and Upf2 binding to the N terminus of Upf3. Here, we identify a conserved domain of hUpf3b that mediates an interaction with the EJC protein Y14. Tethered function analysis shows that the Y14/hUpf3b interaction is essential for NMD, while surprisingly the interaction between hUpf3b and hUpf2 is not. Nonetheless, hUpf2 is necessary for NMD mediated by tethered Y14. RNAi-induced knockdown and Y14 repletion of siRNA-treated cells implicates Y14 in the degradation of beta-globin NS39 mRNA and demonstrates that Y14 is required for NMD induced by tethered hUpf3b. These results uncover a direct role of Y14 in NMD and suggest an unexpected hierarchy in the assembly of NMD complexes.
authors.affiliation: Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Germany.
authors.forename: Niels H
authors.initials: NH
authors.lastname: Gehring
authors.forename: Gabriele
authors.initials: G
authors.lastname: Neu-Yilik
authors.forename: Thomas
authors.initials: T
authors.lastname: Schell
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Hentze
authors.forename: Andreas E
authors.initials: AE
authors.lastname: Kulozik
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D001609:Beta-Globulins / Q000235:genetics / Q000378:metabolism; D018389:Codon, Nonsense / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D005091:Exons / Q000235:genetics*; D006801:Humans; D046911:Macromolecular Substances; D014176:Protein Biosynthesis / Q000235:genetics*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001609:Beta-Globulins; D018389:Codon, Nonsense; D046911:Macromolecular Substances; C406243:RBM8A protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C468286:UPF2 protein, human; C435488:UPF3B protein, human