title: GTP-independent tRNA delivery to the ribosomal P-site by a novel eukaryotic translation factor.
abstract: During translation, aminoacyl-tRNAs are delivered to the ribosome by specialized GTPases called translation factors. Here, we report the tRNA binding to the P-site of 40 S ribosomes by a novel GTP-independent factor eIF2D isolated from mammalian cells. The binding of tRNA(i)(Met) occurs after the AUG codon finds its position in the P-site of 40 S ribosomes, the situation that takes place during initiation complex formation on the hepatitis C virus internal ribosome entry site or on some other specific RNAs (leaderless mRNA and A-rich mRNAs with relaxed scanning dependence). Its activity in tRNA binding with 40 S subunits does not require the presence of the aminoacyl moiety. Moreover, the factor possesses the unique ability to deliver non-Met (elongator) tRNAs into the P-site of the 40 S subunit. The corresponding gene is found in all eukaryotes and includes an SUI1 domain present also in translation initiation factor eIF1. The versatility of translation initiation strategies in eukaryotes is discussed.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Sergey E
authors.initials: SE
authors.lastname: Dmitriev
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Ilya M
authors.initials: IM
authors.lastname: Terenin
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Dmitri E
authors.initials: DE
authors.lastname: Andreev
authors.affiliation: Faculty of Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Pavel A
authors.initials: PA
authors.lastname: Ivanov
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.
authors.forename: Jacov E
authors.initials: JE
authors.lastname: Dunaevsky
authors.affiliation: Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
authors.forename: William C
authors.initials: WC
authors.lastname: Merrick
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia. Electronic address: shatsky@genebee.msu.su.
authors.forename: Ivan N
authors.initials: IN
authors.lastname: Shatsky
mesh_terms: D018387:Codon, Initiator / Q000378:metabolism*; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D039642:Eukaryotic Initiation Factors / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006367:HeLa Cells; D016174:Hepacivirus / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012358:RNA, Transfer, Met / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D054682:Ribosome Subunits, Small, Eukaryotic / Q000378:metabolism*
chemical_list: D018387:Codon, Initiator; C410108:EIF1 protein, human; D015852:Eukaryotic Initiation Factor-2; D039642:Eukaryotic Initiation Factors; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D012346:RNA, Transfer, Amino Acyl; D012358:RNA, Transfer, Met; D012367:RNA, Viral; C000622391:eIF2D protein, human; D006160:Guanosine Triphosphate