title: The role of ABCE1 in eukaryotic posttermination ribosomal recycling.
abstract: After termination, eukaryotic 80S ribosomes remain associated with mRNA, P-site deacylated tRNA, and release factor eRF1 and must be recycled by dissociating these ligands and separating ribosomes into subunits. Although recycling of eukaryotic posttermination complexes (post-TCs) can be mediated by initiation factors eIF3, eIF1, and eIF1A (Pisarev et al., 2007), this energy-free mechanism can function only in a narrow range of low Mg(2+) concentrations. Here, we report that ABCE1, a conserved and essential member of the ATP-binding cassette (ABC) family of proteins, promotes eukaryotic ribosomal recycling over a wide range of Mg(2+) concentrations. ABCE1 dissociates post-TCs into free 60S subunits and mRNA- and tRNA-bound 40S subunits. It can hydrolyze ATP, GTP, UTP, and CTP. NTP hydrolysis by ABCE1 is stimulated by post-TCs and is required for its recycling activity. Importantly, ABCE1 dissociates only post-TCs obtained with eRF1/eRF3 (or eRF1 alone), but not post-TCs obtained with puromycin in eRF1's absence.
authors.affiliation: Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Pisarev
authors.forename: Maxim A
authors.initials: MA
authors.lastname: Skabkin
authors.forename: Vera P
authors.initials: VP
authors.lastname: Pisareva
authors.forename: Olga V
authors.initials: OV
authors.lastname: Skabkina
authors.forename: Aurélie M
authors.initials: AM
authors.lastname: Rakotondrafara
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Hentze
authors.forename: Christopher U T
authors.initials: CU
authors.lastname: Hellen
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Pestova
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D003570:Cytidine Triphosphate / Q000378:metabolism; D039642:Eukaryotic Initiation Factors / Q000502:physiology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D010454:Peptide Termination Factors / Q000378:metabolism; D014176:Protein Biosynthesis; D054657:Ribosome Subunits / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: C501917:ABCE1 protein, human; D018528:ATP-Binding Cassette Transporters; C489002:ETF1 protein, human; D039642:Eukaryotic Initiation Factors; D010454:Peptide Termination Factors; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium; D014544:Uridine Triphosphate