title: PABP enhances release factor recruitment and stop codon recognition during translation termination.
abstract: Poly(A)-binding protein (PABP) is a major component of the messenger RNA-protein complex. PABP is able to bind the poly(A) tail of mRNA, as well as translation initiation factor 4G and eukaryotic release factor 3a (eRF3a). PABP has been found to stimulate translation initiation and to inhibit nonsense-mediated mRNA decay. Using a reconstituted mammalian in vitro translation system, we show that PABP directly stimulates translation termination. PABP increases the efficiency of translation termination by recruitment of eRF3a and eRF1 to the ribosome. PABP's function in translation termination depends on its C-terminal domain and its interaction with the N-terminus of eRF3a. Interestingly, we discover that full-length eRF3a exerts a different mode of function compared to its truncated form eRF3c, which lacks the N-terminal domain. Pre-association of eRF3a, but not of eRF3c, with pre-termination complexes (preTCs) significantly increases the efficiency of peptidyl-tRNA hydrolysis by eRF1. This implicates new, additional interactions of full-length eRF3a with the ribosomal preTC. Based on our findings, we suggest that PABP enhances the productive binding of the eRF1-eRF3 complex to the ribosome, via interactions with the N-terminal domain of eRF3a which itself has an active role in translation termination.
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
authors.forename: Alexandr
authors.initials: A
authors.lastname: Ivanov
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Mikhailova
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France.
authors.forename: Boris
authors.initials: B
authors.lastname: Eliseev
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France.
authors.forename: Lahari
authors.initials: L
authors.lastname: Yeramala
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Sokolova
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
authors.forename: Denis
authors.initials: D
authors.lastname: Susorov
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Alexey
authors.initials: A
authors.lastname: Shuvalov
authors.affiliation: European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, 38042 Grenoble, France School of Biochemistry, University of Bristol, BS8 1TD, UK schaffitzel@embl.fr.
authors.forename: Christiane
authors.initials: C
authors.lastname: Schaffitzel
authors.affiliation: Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia alkalaeva@eimb.ru.
authors.forename: Elena
authors.initials: E
authors.lastname: Alkalaeva
mesh_terms: D018388:Codon, Terminator / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D008954:Models, Biological; D010443:Peptide Chain Termination, Translational / Q000235:genetics*; D010454:Peptide Termination Factors / Q000378:metabolism*; D039102:Poly(A)-Binding Proteins / Q000378:metabolism*; D011485:Protein Binding; D012346:RNA, Transfer, Amino Acyl
chemical_list: D018388:Codon, Terminator; D010454:Peptide Termination Factors; D039102:Poly(A)-Binding Proteins; D012346:RNA, Transfer, Amino Acyl; C087971:peptide-chain-release factor 3; C019037:tRNA, peptidyl-