Weidtkamp-Peters Stefanie, Lenser Thorsten, Negorev Dmitri, Gerstner Norman, Hofmann Thomas G, Schwanitz Georg, Hoischen Christian, Maul Gerd, Dittrich Peter, Hemmerich Peter
Leibniz-Institute of Age Research, Fritz-Lipman-Institute, Beutenbergstr. 11, 07745 Jena, Germany.
J Cell Sci. 2008 Aug 15;121(Pt 16):2731-43. doi: 10.1242/jcs.031922. Epub 2008 Jul 29.
PML nuclear bodies (NBs) are involved in the regulation of key nuclear pathways but their biochemical function in nuclear metabolism is unknown. In this study PML NB assembly dynamics were assessed by live cell imaging and mathematic modeling of its major component parts. We show that all six nuclear PML isoforms exhibit individual exchange rates at NBs and identify PML V as a scaffold subunit. SP100 exchanges at least five times faster at NBs than PML proteins. Turnover dynamics of PML and SP100 at NBs is modulated by SUMOylation. Exchange is not temperature-dependent but depletion of cellular ATP levels induces protein immobilization at NBs. The PML-RARalpha oncogene exhibits a strong NB retention effect on wild-type PML proteins. HIPK2 requires an active kinase for PML NB targeting and elevated levels of PML IV increase its residence time. DAXX and BLM turn over rapidly and completely at PML NBs within seconds. These findings provide a kinetics model for factor exchange at PML NBs and highlight potential mechanisms to regulate intranuclear trafficking of specific factors at these domains.
早幼粒细胞白血病核体（NBs）参与关键核途径的调控，但其在核代谢中的生化功能尚不清楚。在本研究中，通过活细胞成像及其主要组成部分的数学建模评估了早幼粒细胞白血病核体的组装动力学。我们发现所有六种核型早幼粒细胞白血病蛋白在核体处均表现出各自的交换速率，并确定早幼粒细胞白血病蛋白V为支架亚基。SP100在核体处的交换速度比早幼粒细胞白血病蛋白至少快五倍。早幼粒细胞白血病蛋白和SP100在核体处的周转动力学受小泛素样修饰蛋白化调节。交换不依赖温度，但细胞ATP水平的消耗会导致蛋白质固定在核体处。早幼粒细胞白血病视黄酸受体α癌基因对野生型早幼粒细胞白血病蛋白表现出强烈的核体保留效应。HIPK2靶向早幼粒细胞白血病核体需要活性激酶，且早幼粒细胞白血病蛋白IV水平升高会增加其停留时间。DAXX和BLM在数秒内即可在早幼粒细胞白血病核体处迅速且完全地周转。这些发现为早幼粒细胞白血病核体处的因子交换提供了动力学模型，并突出了在这些结构域调节特定因子核内运输的潜在机制。
