title: A highly conserved region essential for NMD in the Upf2 N-terminal domain.
abstract: Upf1, Upf2, and Upf3 are the principal regulators of nonsense-mediated mRNA decay (NMD), a cytoplasmic surveillance pathway that accelerates the degradation of mRNAs undergoing premature translation termination. These three proteins interact with each other, the ribosome, the translation termination machinery, and multiple mRNA decay factors, but the precise mechanism allowing the selective detection and degradation of nonsense-containing transcripts remains elusive. Here, we have determined the crystal structure of the N-terminal mIF4G domain from Saccharomyces cerevisiae Upf2 and identified a highly conserved region in this domain that is essential for NMD and independent of Upf2's binding sites for Upf1 and Upf3. Mutations within this conserved region not only inactivate NMD but also disrupt Upf2 binding to specific proteins, including Dbp6, a DEAD-box helicase. Although current models indicate that Upf2 functions principally as an activator of Upf1 and a bridge between Upf1 and Upf3, our data suggest that it may also serve as a platform for the association of additional factors that play roles in premature translation termination and NMD.
authors.affiliation: Laboratoire de Biochimie, CNRS UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France; Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS UMR 8619, Université Paris Sud, F-91405 Orsay Cedex, France.
authors.forename: Zaineb
authors.initials: Z
authors.lastname: Fourati
authors.affiliation: Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Albert Sherman Center, 368 Plantation Street, Worcester, MA 01655-0122, USA.
authors.forename: Bijoyita
authors.initials: B
authors.lastname: Roy
authors.affiliation: Instituto de Biología Molecular de Barcelona, Spanish Research Council, Barcelona Science Park, Baldiri Reixach 15, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: Claudia
authors.initials: C
authors.lastname: Millan
authors.affiliation: Laboratoire de Biochimie, CNRS UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France.
authors.forename: Pierre-Damien
authors.initials: PD
authors.lastname: Coureux
authors.affiliation: Institut de Biologie Physico-Chimique, CNRS FRE 3630, Université Paris Diderot Sorbonne Paris Cité, F-75005 Paris, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Kervestin
authors.affiliation: Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS UMR 8619, Université Paris Sud, F-91405 Orsay Cedex, France.
authors.forename: Herman
authors.initials: H
authors.lastname: van Tilbeurgh
authors.affiliation: Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Albert Sherman Center, 368 Plantation Street, Worcester, MA 01655-0122, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: Instituto de Biología Molecular de Barcelona, Spanish Research Council, Barcelona Science Park, Baldiri Reixach 15, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Usón
authors.affiliation: Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Albert Sherman Center, 368 Plantation Street, Worcester, MA 01655-0122, USA. Electronic address: allan.jacobson@umassmed.edu.
authors.forename: Allan
authors.initials: A
authors.lastname: Jacobson
authors.affiliation: Laboratoire de Biochimie, CNRS UMR 7654, Ecole Polytechnique, F-91128 Palaiseau Cedex, France; Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS UMR 8619, Université Paris Sud, F-91405 Orsay Cedex, France. Electronic address: marc.graille@polytechnique.edu.
authors.forename: Marc
authors.initials: M
authors.lastname: Graille
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015152:Blotting, Northern; D018360:Crystallography, X-Ray; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D047468:Immunoprecipitation; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D059365:Nonsense Mediated mRNA Decay / Q000235:genetics*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015534:Trans-Activators; D014157:Transcription Factors
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C092470:NMD2 protein, S cerevisiae; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C096360:UPF3 protein, S cerevisiae; C074151:NAM7 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases
keywords: RNA binding; helicase; mIF4G domains; nonsense-mediated mRNA decay