The CryoEM structure of the Saccharomyces cerevisiae ribosome maturation factor Rea1

Elife. 2018 Nov 26;7:e39163. doi: 10.7554/eLife.39163.

Abstract

The biogenesis of 60S ribosomal subunits is initiated in the nucleus where rRNAs and proteins form pre-60S particles. These pre-60S particles mature by transiently interacting with various assembly factors. The ~5000 amino-acid AAA+ ATPase Rea1 (or Midasin) generates force to mechanically remove assembly factors from pre-60S particles, which promotes their export to the cytosol. Here we present three Rea1 cryoEM structures. We visualise the Rea1 engine, a hexameric ring of AAA+ domains, and identify an α-helical bundle of AAA2 as a major ATPase activity regulator. The α-helical bundle interferes with nucleotide-induced conformational changes that create a docking site for the substrate binding MIDAS domain on the AAA +ring. Furthermore, we reveal the architecture of the Rea1 linker, which is involved in force generation and extends from the AAA+ ring. The data presented here provide insights into the mechanism of one of the most complex ribosome maturation factors.

Keywords: AAA+ protein; CryoEM; Rea1; S. cerevisiae; midasin; molecular biophysics; molecular machine; ribosome maturation; structural biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities / chemistry*
  • ATPases Associated with Diverse Cellular Activities / genetics
  • ATPases Associated with Diverse Cellular Activities / metabolism
  • Adenosine Diphosphate / chemistry
  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / chemistry*
  • Adenosine Triphosphate / metabolism
  • Binding Sites
  • Biomechanical Phenomena
  • Cloning, Molecular
  • Cryoelectron Microscopy
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Kinetics
  • Models, Molecular
  • Organelle Biogenesis
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • RNA, Fungal / chemistry
  • RNA, Fungal / metabolism
  • RNA, Ribosomal / chemistry*
  • RNA, Ribosomal / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Ribosomal Proteins / chemistry*
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / metabolism
  • Ribosome Subunits, Large, Eukaryotic / enzymology
  • Ribosome Subunits, Large, Eukaryotic / genetics*
  • Ribosome Subunits, Large, Eukaryotic / ultrastructure
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Substrate Specificity

Substances

  • RNA, Fungal
  • RNA, Ribosomal
  • Recombinant Proteins
  • Ribosomal Proteins
  • Rsa4 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • MDN1 protein, S cerevisiae
  • ATPases Associated with Diverse Cellular Activities