Protein NPM3 interacts with the multifunctional nucleolar protein B23/nucleophosmin and inhibits ribosome biogenesis
Protein NPM3 interacts with the multifunctional nucleolar protein B23/nucleophosmin and inhibits ribosome biogenesis
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DOI：
10.1074/jbc.m407856200
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发表时间：
2005-02-18
影响因子：
4.8
通讯作者：
Olson, MOJ
中科院分区：
文献类型：
--
作者：
Huang, N;Negi, S;Olson, MOJ
蛋白B23/核磷蛋白是一种多功能蛋白，在核糖体生物发生、控制中心体复制和调节p53表达中发挥作用。进行酵母双杂交筛选以寻找B23的相互作用伴侣。在多个阳性克隆中发现了一种高酸性蛋白质核质蛋白3（NPM 3）的互补DNA。蛋白NPM 3及其与B23的相互作用被进一步表征。内源性B23能够与NPM 3免疫共沉淀，并且这种复合物对核糖核酸酶处理和高浓度盐具有抗性。发现B23的N-末端35-90个氨基酸是它们相互作用所需的。B23和NPM 3的单独免疫共沉淀研究表明存在两种不同的复合物，一种含有B23和28 S核糖体RNA（rRNA），另一种由B23，NPM 3和其他蛋白质组成，但没有RNA。NPM 3定位于核仁，其核仁定位依赖于活跃的rRNA转录。在过表达NPM 3的细胞中，前rRNA合成和加工的速率降低。过表达的突变体NPM 3，不与B23相互作用没有改变前rRNA的合成和加工，这表明NPM 3与B23的相互作用在核糖体生物合成中起作用。
Protein B23/nucleophosmin is a multifunctional protein that plays roles in ribosome biogenesis, control of centrosome duplication, and regulation of p53 expression. A yeast two-hybrid screen was performed in a search for interaction partners of B23. The complementary DNA for a highly acidic protein, nucleoplasmin 3 (NPM3), was found in multiple positive clones. Protein NPM3 and its interaction with B23 were further characterized. Endogenous B23 was able to be co-immunoprecipitated with NPM3, and this complex was resistant to ribonuclease treatment and high concentrations of salt. The N-terminal 35-90 amino acids of B23 were found to be required for their interaction. Separate co-immunoprecipitation studies of B23 and NPM3 suggested the existence of two different complexes, one containing B23 and 28 S ribosomal RNA (rRNA) and another composed of B23, NPM3, and other proteins, but no RNA. NPM3 was localized in the nucleolus, and its nucleolar localization depended on active rRNA transcription. In the cells overexpressing NPM3, there were decreased rates of pre-rRNA synthesis and processing. Overexpression of a mutant of NPM3 that did not interact with B23 did not alter pre-rRNA synthesis and processing, suggesting that the interaction of NPM3 with B23 plays a role in the ribosome biogenesis.