title: Human DDX6 effects miRNA-mediated gene silencing via direct binding to CNOT1.
abstract: MicroRNAs (miRNAs) play critical roles in a variety of biological processes through widespread effects on protein synthesis. Upon association with the miRNA-induced silencing complex (miRISC), miRNAs repress target mRNA translation and accelerate mRNA decay. Degradation of the mRNA is initiated by shortening of the poly(A) tail by the CCR4-NOT deadenylase complex followed by the removal of the 5' cap structure and exonucleolytic decay of the mRNA. Here, we report a direct interaction between the large scaffolding subunit of CCR4-NOT, CNOT1, with the translational repressor and decapping activator protein, DDX6. DDX6 binds to a conserved CNOT1 subdomain in a manner resembling the interaction of the translation initiation factor eIF4A with eIF4G. Importantly, mutations that disrupt the DDX6-CNOT1 interaction impair miRISC-mediated gene silencing in human cells. Thus, CNOT1 facilitates recruitment of DDX6 to miRNA-targeted mRNAs, placing DDX6 as a downstream effector in the miRNA silencing pathway.
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada Goodman Cancer Research Centre, McGill University, Montreal, Quebec, H3A 1A3, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Rouya
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada Goodman Cancer Research Centre, McGill University, Montreal, Quebec, H3A 1A3, Canada.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Siddiqui
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada Goodman Cancer Research Centre, McGill University, Montreal, Quebec, H3A 1A3, Canada.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Morita
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada Goodman Cancer Research Centre, McGill University, Montreal, Quebec, H3A 1A3, Canada.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Duchaine
authors.affiliation: Lady Davis Institute for Medical Research, SMBD-Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada marc.fabian@mcgill.ca nahum.sonenberg@mcgill.ca.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Fabian
authors.affiliation: Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada Goodman Cancer Research Centre, McGill University, Montreal, Quebec, H3A 1A3, Canada marc.fabian@mcgill.ca nahum.sonenberg@mcgill.ca.
authors.forename: Nahum
authors.initials: N
authors.lastname: Sonenberg
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: C528690:CNOT1 protein, human; D035683:MicroRNAs; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases
keywords: CCR4–NOT; DDX6; deadenylation; decapping; mRNA decay; microRNA