title: P-body assembly requires DDX6 repression complexes rather than decay or Ataxin2/2L complexes.
abstract: P-bodies are cytoplasmic ribonucleoprotein granules involved in posttranscriptional regulation. DDX6 is a key component of their assembly in human cells. This DEAD-box RNA helicase is known to be associated with various complexes, including the decapping complex, the CPEB repression complex, RISC, and the CCR4/NOT complex. To understand which DDX6 complexes are required for P-body assembly, we analyzed the DDX6 interactome using the tandem-affinity purification methodology coupled to mass spectrometry. Three complexes were prominent: the decapping complex, a CPEB-like complex, and an Ataxin2/Ataxin2L complex. The exon junction complex was also found, suggesting DDX6 binding to newly exported mRNAs. Finally, some DDX6 was associated with polysomes, as previously reported in yeast. Despite its high enrichment in P-bodies, most DDX6 is localized out of P-bodies. Of the three complexes, only the decapping and CPEB-like complexes were recruited into P-bodies. Investigation of P-body assembly in various conditions allowed us to distinguish required proteins from those that are dispensable or participate only in specific conditions. Three proteins were required in all tested conditions: DDX6, 4E-T, and LSM14A. These results reveal the variety of pathways of P-body assembly, which all nevertheless share three key factors connecting P-body assembly to repression.
authors.affiliation: UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France.
authors.forename: Jessica
authors.initials: J
authors.lastname: Ayache
authors.affiliation: UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Bénard
authors.affiliation: UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France.
authors.forename: Michèle
authors.initials: M
authors.lastname: Ernoult-Lange
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom.
authors.forename: Nicola
authors.initials: N
authors.lastname: Minshall
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom.
authors.forename: Nancy
authors.initials: N
authors.lastname: Standart
authors.affiliation: UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Kress
authors.affiliation: UPMC Université de Paris 06, Institut de Biologie Paris-Seine, CNRS UMR-7622, F-75005 Paris, France dominique.weil@upmc.fr.
authors.forename: Dominique
authors.initials: D
authors.lastname: Weil
mesh_terms: D000067698:Ataxin-2 / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism*; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D006801:Humans; D009419:Nerve Tissue Proteins / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000378:metabolism; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism*
chemical_list: C000593752:ATXN2 protein, human; C000600133:ATXN2L protein, human; D000067698:Ataxin-2; C411571:EIF4ENIF1 protein, human; D009419:Nerve Tissue Proteins; D029543:Nucleocytoplasmic Transport Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C510649:RNA-associated protein 55, human; D012261:Ribonucleoproteins; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases