在酵母細胞內(nèi),，每一秒就有2000多個核糖體被合成。核糖體蛋白的快速合成,，高效的運送到細胞核,，并正確的組裝成核糖體亞基，對酵母能夠快速生長是必須的,。
近日,，來自奧地利格拉茨大學的研究人員Brigitte Pertschy等人發(fā)現(xiàn)，錨蛋白重復蛋白Yar1能夠保護核糖體蛋白Rps3免于積聚,。相關論文發(fā)表在5月8日的The Journal of Biological Chemistry,。
Yar1能直接與核糖體小亞基蛋白Rps3相互作用。它伴隨著新和成的Rps3從細胞質(zhì)運送到細胞核,，在細胞核內(nèi)Rps3被組裝成核糖體亞基前體,。
研究發(fā)現(xiàn),，yar1缺失菌株表現(xiàn)出與rps3突變株相似的表型，這表明20S前體rRNA出現(xiàn)累積,，40SrRNA輸出發(fā)生缺陷,。
rps3突變與yar1缺失的組合增強了這些表型，而RPS3的增強表達則會抑制yar1缺失株表現(xiàn)出缺陷特征,。
進一步研究表明,，在體外，Yar1能夠保護Rps3免于積聚,；在體內(nèi),，則能夠增加Rps3的可溶性。
Brigitte Pertschy表示,，Yar1是Rps3特異性的分子伴侶,，能夠保持Rps3的可溶性直到它組裝為核糖體前體。該研究表明了核糖體蛋白需要保護免于積聚的一種機制,。（生物谷Deepblue編譯）
doi: 10.1074/jbc.M112.365791
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Yar1 protects the ribosomal protein Rps3 from aggregation
Barbara Koch, Valentin Mitterer, Johannes Niederhauser, Tamsyn Stanborough, Guillaume Murat, Gerald Rechberger, Helmut Bergler, Dieter Kressler and Brigitte Pertschy.
2000 ribosomes have to be synthesized in yeast every minute. Therefore the fast production of ribosomal proteins, their efficient delivery to the nucleus and correct incorporation into ribosomal subunits are prerequisites for optimal growth rates.Here, we report that the ankyrin repeat protein Yar1 directly interacts with the small ribosomal subunit protein Rps3 and accompanies newly synthesized Rps3 from the cytoplasm into the nucleus where Rps3 is assembled into pre-ribosomal subunits.A yar1 deletion strain displays a similar phenotype as an rps3 mutant strain, showing an accumulation of 20S pre-rRNA and a 40S export defect.The combination of an rps3 mutation with a yar1 deletion leads to an enhancement of these phenotypes, while increased expression of RPS3 suppresses the defects of a yar1 deletion strain.We further show that Yar1 protects Rps3 from aggregation in vitro and increases its solubility in vivo.Our data suggest that Yar1 is a specific chaperone for Rps3, which serves to keep Rps3 soluble until its incorporation into the pre-ribosome.
