Insertion of the Biogenesis Factor Rei1 Probes the Ribosomal Tunnel during 60S Maturation

Cell. 2016 Jan 14;164(1-2):91-102. doi: 10.1016/j.cell.2015.11.027. Epub 2015 Dec 17.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chaetomium / metabolism
  • Cryoelectron Microscopy
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Humans
  • Models, Chemical
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / metabolism
  • Ribosomal Proteins / ultrastructure
  • Ribosome Subunits, Large, Eukaryotic / metabolism*
  • Ribosome Subunits, Large, Eukaryotic / ultrastructure
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Saccharomyces cerevisiae Proteins / ultrastructure
  • Sequence Alignment


  • Alb1 protein, S cerevisiae
  • Arx1 protein, S cerevisiae
  • Fungal Proteins
  • REI1 protein, S cerevisiae
  • Ribosomal Proteins
  • Saccharomyces cerevisiae Proteins