Lamina-associated polypeptide 1 (LAP1) is a nuclear envelope (NE) protein whose function remains poorly characterized. In a recent LAP1 protein interactome study, a putative regulatory role in the DNA damage response (DDR) has emerged and telomeric repeat-binding factor 2 (TRF2), a protein intimately associated with this signaling pathway, was among the list of LAP1 interactors. To gain insights into LAP1′s physiological properties, the interaction with TRF2 in human cells exposed to DNA-damaging agents was investigated. The direct LAP1:TRF2 binding was validated in vitro by blot overlay and in vivo by co-immunoprecipitation after hydrogen peroxide and bleomycin treatments. The regulation of this protein interaction by LAP1 phosphorylation was demonstrated by co-immunoprecipitation and mass spectrometry following okadaic acid exposure. The involvement of LAP1 and TRF2 in the DDR was confirmed by their increased nuclear protein levels after bleomycin treatment, evaluated by immunoblotting, as well as by their co-localization with DDR factors at the NE and within the nucleoplasm, assessed by immunocytochemistry. Effectively, we showed that the LAP1:TRF2 complex is established during a cellular response against DNA damage. This work proposes a novel functional role for LAP1 in the DDR, revealing a potential biological mechanism that may be disrupted in LAP1-associated pathologies.

中文翻译：

---

DNA损伤反应过程中LAP1：TRF2复合物的核积累揭示了LAP1的新作用。

层状相关多肽1（LAP1）是一种核被膜（NE）蛋白，其功能仍然很差。在最近的LAP1蛋白质相互作用组研究中，在DNA损伤反应（DDR）中出现了假定的调节作用，并且端粒重复结合因子2（TRF2）（与该信号通路密切相关的蛋白质）在LAP1相互作用因子中。为了深入了解LAP1的生理特性，研究了在暴露于DNA破坏剂的人类细胞中与TRF2的相互作用。在过氧化氢和博来霉素处理后，通过印迹重叠在体外验证了LAP1：TRF2的直接结合，在体内通过免疫共沉淀验证了LAP1：TRF2的直接结合。冈田酸暴露后，通过免疫共沉淀和质谱证明了LAP1磷酸化对这种蛋白质相互作用的调节。LAP1和TRF2参与DDR是通过博莱霉素处理后核蛋白水平升高（通过免疫印迹评估）以及它们与DDR因子在NE和核质内共定位（通过免疫细胞化学评估）来证实的。有效地，我们表明，在针对DNA损伤的细胞应答过程中建立了LAP1：TRF2复合体。这项工作提出了DDR中LAP1的新功能，揭示了可能在LAP1相关病理中被破坏的潜在生物学机制。在针对DNA损伤的细胞反应过程中建立了TRF2复合物。这项工作提出了DDR中LAP1的新功能，揭示了可能在LAP1相关病理中被破坏的潜在生物学机制。在针对DNA损伤的细胞反应过程中建立了TRF2复合物。这项工作提出了DDR中LAP1的新功能，揭示了可能在LAP1相关病理中被破坏的潜在生物学机制。