Assembly dynamics of PML nuclear bodies in living cells.
Assembly dynamics of PML nuclear bodies in living cells.
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DOI：
10.1186/1757-5036-3-3
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发表时间：
2010-03-05
期刊：
影响因子：
--
通讯作者：
Hemmerich P
中科院分区：
文献类型：
--
作者：
Brand P;Lenser T;Hemmerich P
哺乳动物细胞核包含各种细胞器或核体，它们有助于关键的核功能。早幼粒细胞白血病核体（PML NB）参与细胞凋亡、抗病毒反应、DNA损伤反应和染色质结构的调节，但它们在这些核途径中的精确生化功能尚不清楚。解决这个问题的一个策略是评估活细胞中这些大分子组装体的组成部分的生物物理特性。在这项研究中，我们确定了PML NB组装动力学活细胞成像，结合数学建模。首次在缺乏内源性PML的细胞中测定了PML小体形成的动力学。我们发现，所有六种人类核PML亚型都能够在PML阴性细胞中形成核体。所有亚型在PML阳性细胞中的NB处均表现出个体交换率，但PML I、II、III和IV在PML阴性细胞中的核体处是静态的，这表明这些亚型需要额外的蛋白质伴侣来进行有效交换。PML V在PML Nbs处非常缓慢地转变，支持该同种型的结构功能的想法。我们还证明了PML在赖氨酸位置K160和/或K490的SUMO化是体内核体形成所必需的，我们提出了一个模型，其中PML的异构体特异性停留时间提供了结构稳定性以作为支架和灵活性以吸引特异性核蛋白在核体表面进行有效的生化反应。MCS代码：92 C37
The mammalian cell nucleus contains a variety of organelles or nuclear bodies which contribute to key nuclear functions. Promyelocytic leukemia nuclear bodies (PML NBs) are involved in the regulation of apoptosis, antiviral responses, the DNA damage response and chromatin structure, but their precise biochemical function in these nuclear pathways is unknown. One strategy to tackle this problem is to assess the biophysical properties of the component parts of these macromolecular assemblies in living cells. In this study we determined PML NB assembly dynamics by live cell imaging, combined with mathematical modeling. For the first time, dynamics of PML body formation were measured in cells lacking endogenous PML. We show that all six human nuclear PML isoforms are able to form nuclear bodies in PML negative cells. All isoforms exhibit individual exchange rates at NBs in PML positive cells but PML I, II, III and IV are static at nuclear bodies in PML negative cells, suggesting that these isoforms require additional protein partners for efficient exchange. PML V turns over at PML Nbs very slowly supporting the idea of a structural function for this isoform. We also demonstrate that SUMOylation of PML at Lysine positions K160 and/or K490 are required for nuclear body formation in vivo.We propose a model in which the isoform specific residence times of PML provide both, structural stability to function as a scaffold and flexibility to attract specific nuclear proteins for efficient biochemical reactions at the surface of nuclear bodies. MCS code: 92C37