PDF(Pubmed)
Abstract：
The Parkinson\'s-associated protein α-synuclein (α-syn) can undergo liquid-liquid phase separation (LLPS), which typically leads to the formation of amyloid fibrils. The coincidence of LLPS and amyloid formation has complicated the identification of the molecular determinants unique to LLPS of α-syn. Moreover, the lack of strategies to selectively perturb LLPS makes it difficult to dissect the biological roles specific to α-syn LLPS, independent of fibrillation. Herein, using a combination of subtle missense mutations, we show that LLPS of α-syn is highly sensitive to its sequence complexity. In fact, we find that even a highly conservative mutation (V16I) that increases sequence complexity without perturbing physicochemical and structural properties, is sufficient to reduce LLPS by 75%; this effect can be reversed by an adjacent V-to-I mutation (V15I) that restores the original sequence complexity. A18T, a complexity-enhancing PD-associated mutation, was likewise found to reduce LLPS, implicating sequence complexity in α-syn pathogenicity. Furthermore, leveraging the differences in LLPS propensities among different α-syn variants, we demonstrate that fibrillation of α-syn does not necessarily correlate with its LLPS. In fact, we identify mutations that selectively perturb LLPS or fibrillation of α-syn, unlike previously studied mutations. The variants and design principles reported herein should therefore empower future studies to disentangle these two phenomena and distinguish their (patho)biological roles.
摘要：
帕金森相关蛋白α-突触核蛋白(α-syn)可以进行液-液相分离(LLPS),这通常导致淀粉样原纤维的形成。LLPS和淀粉样蛋白形成的重合使α-syn的LLPS特有的分子决定簇的鉴定变得复杂。此外，缺乏选择性干扰LLPS的策略使得难以剖析α-synLLPS特有的生物学作用，独立于纤颤。在这里，使用微妙的错义突变的组合，我们表明α-syn的LLPS对其序列复杂性高度敏感。事实上,我们发现，即使是高度保守的突变（V16I），增加序列的复杂性，而不干扰物理化学和结构性质，足以将LLPS降低75%;这种效应可以通过恢复原始序列复杂性的相邻V到I突变(V15I)来逆转。A18T,复杂性增强的PD相关突变，同样被发现降低LLPS，α-syn致病性涉及序列复杂性。此外，利用不同α-syn变体之间LLPS倾向的差异，我们证明α-syn的原纤化不一定与其LLPS相关。事实上,我们确定了选择性干扰LLPS或α-syn纤维化的突变，与以前研究的突变不同。因此，本文报道的变体和设计原理应赋予未来的研究以解开这两种现象并区分它们的（病理）生物学作用。
