Activation and control of p53 tetramerization in individual living cells
Activation and control of p53 tetramerization in individual living cells
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DOI：
10.1073/pnas.1311126110
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发表时间：
2013-09-17
影响因子：
11.1
通讯作者：
Lahav, Galit
中科院分区：
文献类型：
--
作者：
Gaglia, Giorgio;Guan, Yinghua;Lahav, Galit
齐聚反应广泛存在于多种生物体系中，并在体外得到了广泛的研究。然而，我们量化和理解细胞内齐聚过程的能力仍然有限。我们使用荧光相关光谱和数学模型来测量肿瘤抑制蛋白P53在单个活细胞中形成的四聚体的动力学。先前的体外研究表明，在基础条件下，所有的p53分子都结合在二聚体中。我们发现，在静息细胞中，P53以一种低聚状态的混合形式存在，细胞间的差异很大。DNA损伤后，所有细胞中的P53分子在P53蛋白水平增加之前迅速组装成四聚体。我们开发了一个模型来理解P53积累和四聚化之间的联系。我们发现，P53四聚体的快速增加需要活跃的四聚体和蛋白质稳定性的结合，然而仅四聚体就足以激活P53转录靶标。这表明，触发四聚化是激活癌细胞中P53途径的一种机制。许多其他转录因子都是同源寡聚的，我们的方法为探索寡聚的动力学和功能后果提供了一种独特的方法。
Homo-oligomerization is found in many biological systems and has been extensively studied in vitro. However, our ability to quantify and understand oligomerization processes in cells is still limited. We used fluorescence correlation spectroscopy and mathematical modeling to measure the dynamics of the tetramers formed by the tumor suppressor protein p53 in single living cells. Previous in vitro studies suggested that in basal conditions all p53 molecules are bound in dimers. We found that in resting cells p53 is present in a mix of oligomeric states with a large cell-to-cell variation. After DNA damage, p53 molecules in all cells rapidly assemble into tetramers before p53 protein levels increase. We developed a model to understand the connection between p53 accumulation and tetramerization. We found that the rapid increase in p53 tetramers requires a combination of active tetramerization and protein stabilization, however tetramerization alone is sufficient to activate p53 transcriptional targets. This suggests triggering tetramerization as a mechanism for activating the p53 pathway in cancer cells. Many other transcription factors homo-oligomerize, and our approach provides a unique way for probing the dynamics and functional consequences of oligomerization.