Liu Shuaiyu, Xiong Fangyuan, Dou Zhen, Chu Lingluo, Yao Yihan, Wang Ming, Yao Xuebiao, Liu Xing, Wang Zhikai
MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, Hefei, China; Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, China.
MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
J Biol Chem. 2025 Jan;301(1):108033. doi: 10.1016/j.jbc.2024.108033. Epub 2024 Nov 28.
Dynamic disassembly and reconstruction of the nuclear lamina during entry and exit of mitosis, respectively, are pivotal steps in the proliferation of higher eukaryotic cells. Although numerous post-translational modifications of lamin proteins have been identified, key factors driving the nuclear lamina dynamics remain elusive. Here we identified CDK1-elicited phosphorylation sites on endogenous Lamin A/C and characterized their functions in regulation of the nuclear lamina. Specifically, mass spectrometry revealed CDK1-mediated phosphorylation of Lamin A/C at the N-terminal Thr19/Ser22 and the C-terminal Ser390/Ser392 during mitosis. Importantly, the phospho-mimicking 4D mutant T19D/S22D/S390D/S392D completely disrupted Lamin A filamentous structure in interphase cells. Conversely, the non-phosphorylatable mutant T19A/S22A and especially the 4A mutant T19A/S22A/S390A/S392A protected Lamin A from depolymerization during mitosis. These results suggest that phosphorylation and dephosphorylation of both N- and C-terminal sites regulate the nuclear lamina dynamics. Engineering the non-phosphorylatable mutant T19A/S22A into the endogenous LMNA gene resulted in nuclear abnormalities and micronucleus formation during telophase. Perturbation of the Lamin A phosphorylation is shown to prevent proper nuclear envelope dynamics and impair nuclear integrity. These findings reveal a previously undefined link between the CDK1-elicited Lamin A phosphorylation dynamics, nuclear envelope plasticity, and genomic stability during the cell cycle.
在有丝分裂进入和退出过程中，核纤层分别进行动态拆卸和重建，这是高等真核细胞增殖的关键步骤。尽管已鉴定出核纤层蛋白的多种翻译后修饰，但驱动核纤层动态变化的关键因素仍不清楚。在此，我们鉴定了内源性核纤层蛋白A/C上由细胞周期蛋白依赖性激酶1（CDK1）引发的磷酸化位点，并表征了它们在调节核纤层中的功能。具体而言，质谱分析显示在有丝分裂期间，CDK1介导核纤层蛋白A/C在N端的苏氨酸19/丝氨酸22以及C端的丝氨酸390/丝氨酸392处发生磷酸化。重要的是，模拟磷酸化的4D突变体T19D/S22D/S390D/S392D完全破坏了间期细胞中核纤层蛋白A的丝状结构。相反，不可磷酸化的突变体T19A/S22A，尤其是4A突变体T19A/S22A/S390A/S392A在有丝分裂期间保护核纤层蛋白A不发生解聚。这些结果表明，N端和C端位点的磷酸化和去磷酸化调节核纤层的动态变化。将不可磷酸化的突变体T19A/S22A导入内源性LMNA基因会导致末期出现核异常和微核形成。核纤层蛋白A磷酸化的扰动被证明会阻止核膜的正常动态变化并损害核完整性。这些发现揭示了细胞周期中CDK1引发的核纤层蛋白A磷酸化动态变化、核膜可塑性和基因组稳定性之间以前未被定义的联系。
