Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, China.
School of Chemistry and Bioengineering, Nanjing Normal University Taizhou College, Taizhou 225300, China.
Biomolecules. 2023 Apr 23;13(5):726. doi: 10.3390/biom13050726.
The Lewy bodies and Lewy neurites are key pathological hallmarks of Parkinson's disease (PD). Single-point mutations associated with familial PD cause α-synuclein (α-Syn) aggregation, leading to the formation of Lewy bodies and Lewy neurites. Recent studies suggest α-Syn nucleates through liquid-liquid phase separation (LLPS) to form amyloid aggregates in a condensate pathway. How PD-associated mutations affect α-Syn LLPS and its correlation with amyloid aggregation remains incompletely understood. Here, we examined the effects of five mutations identified in PD, A30P, E46K, H50Q, A53T, and A53E, on the phase separation of α-Syn. All other α-Syn mutants behave LLPS similarly to wild-type (WT) α-Syn, except that the E46K mutation substantially promotes the formation of α-Syn condensates. The mutant α-Syn droplets fuse to WT α-Syn droplets and recruit α-Syn monomers into their droplets. Our studies showed that α-Syn A30P, E46K, H50Q, and A53T mutations accelerated the formation of amyloid aggregates in the condensates. In contrast, the α-Syn A53E mutant retarded the aggregation during the liquid-to-solid phase transition. Finally, we observed that WT and mutant α-Syn formed condensates in the cells, whereas the E46K mutation apparently promoted the formation of condensates. These findings reveal that familial PD-associated mutations have divergent effects on α-Syn LLPS and amyloid aggregation in the phase-separated condensates, providing new insights into the pathogenesis of PD-associated α-Syn mutations.
路易体和路易神经纤维是帕金森病（PD）的关键病理标志物。与家族性 PD 相关的单点突变导致α-突触核蛋白（α-Syn）聚集，导致路易体和路易神经纤维的形成。最近的研究表明，α-Syn 通过液-液相分离（LLPS）形成凝聚物途径中的淀粉样蛋白聚集物。PD 相关突变如何影响 α-Syn LLPS 及其与淀粉样蛋白聚集的相关性仍不完全清楚。在这里，我们研究了在 PD 中发现的五个突变（A30P、E46K、H50Q、A53T 和 A53E）对α-Syn 相分离的影响。除了 E46K 突变显著促进α-Syn 凝聚物的形成外，所有其他α-Syn 突变体的 LLPS 行为与 WT α-Syn 相似。突变的α-Syn 液滴融合到 WT α-Syn 液滴中，并将α-Syn 单体招募到其液滴中。我们的研究表明，α-Syn A30P、E46K、H50Q 和 A53T 突变加速了凝聚物中淀粉样蛋白聚集物的形成。相比之下，α-Syn A53E 突变在液-固相变过程中减缓了聚集。最后，我们观察到 WT 和突变的α-Syn 在细胞中形成凝聚物，而 E46K 突变显然促进了凝聚物的形成。这些发现表明，家族性 PD 相关突变对α-Syn LLPS 和相分离凝聚物中的淀粉样蛋白聚集具有不同的影响，为 PD 相关α-Syn 突变的发病机制提供了新的见解。
