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

The CryoEM structure of the Saccharomyces cerevisiae ribosome maturation factor Rea1.

Sosnowski P#1,2,3,4, Urnavicius L#5, Boland A5, Fagiewicz R1,2,3,4, Busselez J1,2,3,4, Papai G1,2,3,4, Schmidt H1,2,3,4.

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Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.
Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.
Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.
Université de Strasbourg, Illkirch, France.
Division of Structural Studies, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.
Contributed equally


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.


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

[Indexed for MEDLINE]
Free PMC Article

Conflict of interest statement

PS, LU, AB, RF, JB, GP, HS No competing interests declared

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