The CryoEM structure of the Saccharomyces cerevisiae ribosome maturation factor Rea1
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, France
- MRC Laboratory of Molecular Biology, United Kingdom
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 visualize 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.
Data availability
The atomic coordinates for the Rea1 AAA+ ring and the Rea1 linker in the ADP state have been deposited with PDB IDs 6HYP and 6HYD, respectively. The accession codes for the Rea1 and Rea1_ΔAAA2L-H2α models in the AMPPNP state are 6I26 and 6I27, respectively. The accession codes for the cryoEM maps of the Rea1 AAA+ ring and the Rea1 linker in the ADP state are EMD-0309 and EMD-0308, respectively. The accession code for the unsharpened cryoEM map of the Rea1 AAA+ ring in the ADP state is EMD-0330. The cryoEM maps of the Rea1 and Rea1_ΔAAA2L-H2α AMPPNP states have the EMD accession codes EMD-0328 and EMD-0329, respectively.
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Sharpened map of the Rea1 AAA+ ring ADP stateElectron Microscopy Data Bank, EMD-0309.
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Unsharpened map of the Rea1 linker ADP stateElectron Microscopy Data Bank, EMD-0308.
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Unsharpened map of the Rea1 AAA+ ring ADP stateElectron Microscopy Data Bank, EMD-0330.
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Sharpened map of the Rea1 AMPPNP stateElectron Microscopy Data Bank, EMD-0328.
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Sharpened map of the Rea1_ΔAAA2L-H2α AMPPNP stateElectron Microscopy Data Bank, EMD-0329.
Article and author information
Author details
Funding
HS-ATIP-avenir grant (CDP 0B1INSB-HS-9ADO1051)
- Helgo Schmidt
LabEX startup grant (GIE I-LABEX-HS)
- Helgo Schmidt
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2018, Sosnowski et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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The CryoEM structure of the Saccharomyces cerevisiae ribosome maturation factor Rea1
eLife 7:e39163.
https://doi.org/10.7554/eLife.39163
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