Yan Xiao, Kuster David, Mohanty Priyesh, Nijssen Jik, Pombo-García Karina, Rizuan Azamat, Franzmann Titus M, Sergeeva Aleksandra, Passos Patricia M, George Leah, Wang Szu-Huan, Shenoy Jayakrishna, Danielson Helen L, Honigmann Alf, Ayala Yuna M, Fawzi Nicolas L, Mittal Jeetain, Alberti Simon, Hyman Anthony A
Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG); Dresden, Saxony, 01307; Germany.
These authors contributed equally.
bioRxiv. 2024 May 24:2024.01.23.576837. doi: 10.1101/2024.01.23.576837.
Cytosolic aggregation of the nuclear protein TDP-43 is associated with many neurodegenerative diseases, but the triggers for TDP-43 aggregation are still debated. Here, we demonstrate that TDP-43 aggregation requires a double event. One is up-concentration in stress granules beyond a threshold, and the other is oxidative stress. These two events collectively induce intra-condensate demixing, giving rise to a dynamic TDP-43 enriched phase within stress granules, which subsequently transitions into pathological aggregates. Mechanistically, intra-condensate demixing is triggered by local unfolding of the RRM1 domain for intermolecular disulfide bond formation and by increased hydrophobic patch interactions in the C-terminal domain. By engineering TDP-43 variants resistant to intra-condensate demixing, we successfully eliminate pathological TDP-43 aggregates in cells. We conclude that up-concentration inside condensates and simultaneous exposure to environmental stress could be a general pathway for protein aggregation, with intra-condensate demixing constituting a key intermediate step.
核蛋白TDP - 43的胞质聚集与许多神经退行性疾病相关，但TDP - 43聚集的触发因素仍存在争议。在此，我们证明TDP - 43聚集需要双重事件。一是在应激颗粒中浓度升高超过阈值，另一个是氧化应激。这两个事件共同诱导凝聚物内部分相，在应激颗粒内产生一个动态的富含TDP - 43的相，随后转变为病理性聚集体。从机制上讲，凝聚物内部分相是由RRM1结构域的局部解折叠以形成分子间二硫键以及C末端结构域中增加的疏水补丁相互作用触发的。通过构建对凝聚物内部分相具有抗性的TDP - 43变体，我们成功消除了细胞中的病理性TDP - 43聚集体。我们得出结论，凝聚物内的浓度升高和同时暴露于环境应激可能是蛋白质聚集的一般途径，凝聚物内部分相构成关键的中间步骤。
