title: Insertion of the Biogenesis Factor Rei1 Probes the Ribosomal Tunnel during 60S Maturation.
abstract: Eukaryotic ribosome biogenesis depends on several hundred assembly factors to produce functional 40S and 60S ribosomal subunits. The final phase of 60S subunit biogenesis is cytoplasmic maturation, which includes the proofreading of functional centers of the 60S subunit and the release of several ribosome biogenesis factors. We report the cryo-electron microscopy (cryo-EM) structure of the yeast 60S subunit in complex with the biogenesis factors Rei1, Arx1, and Alb1 at 3.4 Å resolution. In addition to the network of interactions formed by Alb1, the structure reveals a mechanism for ensuring the integrity of the ribosomal polypeptide exit tunnel. Arx1 probes the entire set of inner-ring proteins surrounding the tunnel exit, and the C terminus of Rei1 is deeply inserted into the ribosomal tunnel, where it forms specific contacts along almost its entire length. We provide genetic and biochemical evidence that failure to insert the C terminus of Rei1 precludes subsequent steps of 60S maturation.
authors.affiliation: Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Basil Johannes
authors.initials: BJ
authors.lastname: Greber
authors.affiliation: Institute of Biochemistry, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Gerhardy
authors.affiliation: Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Leitner
authors.affiliation: Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Leibundgut
authors.affiliation: Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, 75006 Paris, France.
authors.forename: Michèle
authors.initials: M
authors.lastname: Salem
authors.affiliation: Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Boehringer
authors.affiliation: Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, 75006 Paris, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Leulliot
authors.affiliation: Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland; Faculty of Science, University of Zurich, CH-8057 Zurich, Switzerland.
authors.forename: Ruedi
authors.initials: R
authors.lastname: Aebersold
authors.affiliation: Institute of Biochemistry, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland. Electronic address: vikram.panse@bc.biol.ethz.ch.
authors.forename: Vikram Govind
authors.initials: VG
authors.lastname: Panse
authors.affiliation: Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland. Electronic address: ban@mol.biol.ethz.ch.
authors.forename: Nenad
authors.initials: N
authors.lastname: Ban
mesh_terms: D000595:Amino Acid Sequence; D002597:Chaetomium / Q000378:metabolism; D020285:Cryoelectron Microscopy; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D016415:Sequence Alignment
chemical_list: C000607951:Alb1 protein, S cerevisiae; C546625:Arx1 protein, S cerevisiae; D005656:Fungal Proteins; C511835:REI1 protein, S cerevisiae; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins