Finch R A, Chan P K
Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030, USA.
Biochem Biophys Res Commun. 1996 May 15;222(2):553-8. doi: 10.1006/bbrc.1996.0782.
Nucleophosmin/B23 (NPM) is a nucleolar phosphoprotein which shifts from nucleoli to the nucleoplasm in cells treated with certain cytotoxic agents (NPM-translocation). NPM requires GTP for localization into nucleoli (J. Biol. Chem. 268, 5823-5827, 1993). To understand more about NPM's dynamic localization, the effects of lowering ATP on NPM-translocation and rRNA synthesis were studied. When the ATP level in HeLa cells was reduced by sodium azide, NPM-translocation was blocked. Similar results were obtained when ATP was depleted by other agents, suggesting that ATP depletion was responsible for the blocking of NPM-translocation. It was found that newly synthesized rRNA accumulated in the nuclei during ATP-depletion. Significantly larger than normal nucleoli were also observed. These results indicate that NPM may be involved in the transportation of newly synthesized ribosomes.
核磷蛋白/B23（NPM）是一种核仁磷蛋白，在用某些细胞毒性药物处理的细胞中，它会从核仁转移到核质中（NPM易位）。NPM定位于核仁需要GTP（《生物化学杂志》268卷，5823 - 5827页，1993年）。为了更深入了解NPM的动态定位，研究了降低ATP对NPM易位和rRNA合成的影响。当叠氮化钠降低HeLa细胞中的ATP水平时，NPM易位被阻断。当用其他试剂耗尽ATP时也得到了类似结果，表明ATP耗竭是NPM易位受阻的原因。研究发现，在ATP耗竭期间，新合成的rRNA在细胞核中积累。还观察到明显大于正常的核仁。这些结果表明，NPM可能参与新合成核糖体的运输。
