Pertschy B, et al. (2007) Cytoplasmic Recycling of 60S Preribosomal Factors Depends on the AAA Protein Drg1. Mol Cell Biol 27(19):6581-92
Abstract: Allelic forms of DRG1/AFG2 confer resistance to the drug diazaborine, an inhibitor of ribosome biogenesis in yeast. Our results show that the AAA-ATPase Drg1 is essential for 60S maturation and associates with 60S precursor particles in the cytoplasm. Functional inactivation of Drg1 leads to an increased cytoplasmic localization of shuttling pre-60S maturation factors like Rlp24, Arx1 and Tif6. Surprisingly, Nog1, a nuclear pre-60S factor, was also relocalized to the cytoplasm under these conditions, suggesting that it is a previously unsuspected shuttling pre-ribosomal factor that is exported with the precursor particles and very rapidly reimported. Proteins that became cytoplasmic under drg1 mutant conditions were blocked on pre-60S particles at a step that precedes the association of Rei1, a later acting pre-ribosomal factor. A similar cytoplasmic accumulation of Nog1 and Rlp24 in pre-60S bound form could be seen after overexpression of a dominant negative Drg1 variant mutated in the D2 ATPase domain. We conclude that the ATPase activity of Drg1 is required for the release of shuttling proteins from the pre-60S particles shortly after their nuclear export. This early cytoplasmic release reaction defines a novel step in eukaryotic ribosome maturation.
|Status: Published||Type: Journal Article||PubMed ID: 17646390|
Topics addressed in this paper
Number of different genes curated to this paper: 8
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