Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czech Republic.
Institute of Physiology of the Czech Academy of Sciences, Laboratory of Structural Biology of Signaling Proteins, Division BIOCEV, Vestec, Czech Republic.
Protein Sci. 2022 May;31(5):e4287. doi: 10.1002/pro.4287.
Transcription factor p53 protects cells against tumorigenesis when subjected to various cellular stresses. Under these conditions, p53 interacts with transcription factor Forkhead box O (FOXO) 4, thereby inducing cellular senescence by upregulating the transcription of senescence-associated protein p21. However, the structural details of this interaction remain unclear. Here, we characterize the interaction between p53 and FOXO4 by NMR, chemical cross-linking, and analytical ultracentrifugation. Our results reveal that the interaction between p53 TAD and the FOXO4 Forkhead domain is essential for the overall stability of the p53:FOXO4 complex. Furthermore, contacts involving the N-terminal segment of FOXO4, the C-terminal negative regulatory domain of p53 and the DNA-binding domains of both proteins stabilize the complex, whose formation blocks p53 binding to DNA but without affecting the DNA-binding properties of FOXO4. Therefore, our structural findings may help to understand the intertwined functions of p53 and FOXO4 in cellular homeostasis, longevity, and stress response.
转录因子 p53 在细胞受到各种细胞应激时，可保护细胞免受肿瘤形成。在这些条件下，p53 与转录因子叉头框 O（FOXO）4 相互作用，从而通过上调衰老相关蛋白 p21 的转录诱导细胞衰老。然而，这种相互作用的结构细节尚不清楚。在这里，我们通过 NMR、化学交联和分析超速离心来描述 p53 和 FOXO4 之间的相互作用。我们的结果表明，p53 TAD 与 FOXO4 叉头结构域之间的相互作用对于 p53：FOXO4 复合物的整体稳定性至关重要。此外，涉及 FOXO4 的 N 端片段、p53 的 C 端负调节结构域以及这两种蛋白质的 DNA 结合结构域的接触稳定了该复合物，其形成阻止了 p53 与 DNA 的结合，但不影响 FOXO4 的 DNA 结合特性。因此，我们的结构研究结果可能有助于理解 p53 和 FOXO4 在细胞内稳态、长寿和应激反应中的相互交织的功能。
