Lysine 40 acetylation of α-tubulin (Ac-α-tubulin), catalyzed by the acetyltransferase αTAT1, marks stabilized microtubules. Recently, there is growing evidence to suggest crosstalk between the DNA damage response (DDR) and microtubule organization; we therefore investigated whether αTAT1 is involved in the DDR. Following treatment with DNA-damaging agents, increased levels of Ac-α-tubulin were detected. We also observed significant induction of Ac-α-tubulin after depletion of DNA repair proteins, suggesting that αTAT1 is positively regulated in response to DNA damage. Intriguingly, αTAT1 depletion decreased DNA damage-induced replication protein A (RPA) phosphorylation and foci formation. Moreover, DNA damage-induced cell cycle arrest was significantly delayed in αTAT1-depleted cells, indicating defective checkpoint activation. The checkpoint defects seen upon αTAT1 deficiency were restored by expression of wild-type αTAT1, but not by αTAT1-D157N (a catalytically inactive αTAT1), indicating that the role of αTAT1 in the DDR is dependent on enzymatic activity. Furthermore, αTAT1-depleted direct repeat GFP (DR-GFP) U2OS cells had a significant decrease in the frequency of homologous recombination repair. Collectively, our results suggest that αTAT1 may play an essential role in DNA damage checkpoints and DNA repair through its acetyltransferase activity.

由乙酰转移酶 αTAT1 催化的 α-微管蛋白 (Ac-α-微管蛋白) 的赖氨酸 40 乙酰化标记稳定的微管。最近，越来越多的证据表明 DNA 损伤反应 (DDR) 和微管组织之间存在串扰。因此，我们调查了 αTAT1 是否参与 DDR。在用 DNA 损伤剂处理后，检测到 Ac-α-微管蛋白水平升高。我们还观察到 DNA 修复蛋白耗尽后 Ac-α-微管蛋白的显着诱导，表明 αTAT1 响应 DNA 损伤受到正调节。有趣的是，αTAT1 消耗降低了 DNA 损伤诱导的复制蛋白 A (RPA) 磷酸化和病灶形成。此外，在 αTAT1 耗尽的细胞中，DNA 损伤诱导的细胞周期停滞显着延迟，表明检查点激活有缺陷。通过野生型 αTAT1 的表达，而不是通过 αTAT1-D157N（无催化活性的 αTAT1）的表达恢复了在 αTAT1 缺乏时观察到的检查点缺陷，这表明 αTAT1 在 DDR 中的作用取决于酶活性。此外，αTAT1 耗尽的直接重复 GFP (DR-GFP) U2OS 细胞的同源重组修复频率显着降低。总的来说，我们的研究结果表明，αTAT1 可能通过其乙酰转移酶活性在 DNA 损伤检查点和 DNA 修复中发挥重要作用。αTAT1 耗尽的直接重复 GFP (DR-GFP) U2OS 细胞的同源重组修复频率显着降低。总的来说，我们的研究结果表明，αTAT1 可能通过其乙酰转移酶活性在 DNA 损伤检查点和 DNA 修复中发挥重要作用。αTAT1 耗尽的直接重复 GFP (DR-GFP) U2OS 细胞的同源重组修复频率显着降低。总的来说，我们的研究结果表明，αTAT1 可能通过其乙酰转移酶活性在 DNA 损伤检查点和 DNA 修复中发挥重要作用。