Cytoplasmic recycling of 60S preribosomal factors depends on the AAA protein Drg1.
Mol Cell Biol
; 27(19): 6581-92, 2007 Oct.
Article
em En
| MEDLINE
| ID: mdl-17646390
ABSTRACT
Allelic forms of DRG1/AFG2 confer resistance to the drug diazaborine, an inhibitor of ribosome biogenesis in Saccharomyces cerevisiae. 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 preribosomal 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 preribosomal 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.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Precursores de Proteínas
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Saccharomyces cerevisiae
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Adenosina Trifosfatases
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Citoplasma
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Proteínas de Saccharomyces cerevisiae
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Subunidades Ribossômicas Maiores de Eucariotos
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article