Proteins including FUS, hnRNPA2, and TDP-43 reversibly aggregate into amyloid-like fibrils through interactions of their low-complexity domains (LCDs). Mutations in LCDs can promote irreversible amyloid aggregation and disease. We introduce a computational approach to identify mutations in LCDs of disease-associated proteins predicted to increase propensity for amyloid aggregation. We identify several disease-related mutations in the intermediate filament protein keratin-8 (KRT8). Atomic structures of wild-type and mutant KRT8 segments confirm the transition to a pleated strand capable of amyloid formation. Biochemical analysis reveals KRT8 forms amyloid aggregates, and the identified mutations promote aggregation. Aggregated KRT8 is found in Mallory–Denk bodies, observed in hepatocytes of livers with alcoholic steatohepatitis (ASH). We demonstrate that ethanol promotes KRT8 aggregation, and KRT8 amyloids co-crystallize with alcohol. Lastly, KRT8 aggregation can be seeded by liver extract from people with ASH, consistent with the amyloid nature of KRT8 aggregates and the classification of ASH as an amyloid-related condition.

包括 FUS、hnRNPA2 和 TDP-43 在内的蛋白质通过其低复杂性结构域 (LCD) 的相互作用可逆地聚集成淀粉样蛋白样原纤维。LCD 中的突变可以促进不可逆的淀粉样蛋白聚集和疾病。我们引入了一种计算方法来识别预测会增加淀粉样蛋白聚集倾向的疾病相关蛋白的 LCD 突变。我们在中间丝蛋白角蛋白 8 (KRT8) 中发现了几种与疾病相关的突变。野生型和突变型 KRT8 片段的原子结构证实了向能够形成淀粉样蛋白的折叠链的转变。生化分析显示 KRT8 形成淀粉样蛋白聚集体，并且已识别的突变促进聚集。聚集的 KRT8 存在于 Mallory-Denk 体中，在酒精性脂肪性肝炎 (ASH) 的肝脏肝细胞中观察到。我们证明乙醇促进 KRT8 聚集，并且 KRT8 淀粉样蛋白与酒精共结晶。最后，KRT8 聚集体可以通过 ASH 患者的肝脏提取物接种，这与 KRT8 聚集体的淀粉样蛋白性质和 ASH 分类为淀粉样蛋白相关病症一致。