The composition of the polyglutamine-containing proteins influences their co-aggregation properties
The composition of the polyglutamine-containing proteins influences their co-aggregation properties
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DOI：
10.1042/cbi20090474
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发表时间：
2010-09-01
影响因子：
3.9
通讯作者：
Milewski, Michel
中科院分区：
文献类型：
--
作者：
Bak, Daniel;Milewski, Michel
关键细胞蛋白质螯合成由含有扩展的多聚谷氨酰胺束的多肽形成的不溶性聚集体已被提出是负责所谓的多聚谷氨酰胺疾病中的异常细胞功能的关键机制。为了评估多聚谷氨酰胺序列在多大程度上招募其他蛋白质进入细胞内聚集体的能力取决于聚集肽的组成，我们分析了亨廷顿蛋白的N-末端片段与不相关的非聚集和/或自聚集肽融合的共聚集特性。我们表明，突变的N-末端亨廷顿蛋白片段螯合非相关蛋白的能力可以显着增加与非聚集性报告蛋白[GFP（绿色荧光蛋白）]融合。相比之下，与CFTR（囊性纤维化跨膜传导调节因子）的自聚集C末端片段的融合显著减少了相关非融合亨廷顿蛋白片段的隔离。我们还表明，不同的非融合的N-末端亨廷顿蛋白片段的共聚集取决于它们的长度，与野生型亨廷顿蛋白的长片段不仅排除从核内含物，但也非常低效地隔离到由突变蛋白的短片段形成的细胞质聚集体。此外，我们的研究结果表明，非典型的细胞内聚集模式，其中包括不寻常的分布和/或形态的蛋白质聚集体，与改变的能力积累蛋白质与其他肽共聚集。
The sequestration of crucial cellular proteins into insoluble aggregates formed by the polypeptides containing expanded polyglutamine tracts has been proposed to be the key mechanism responsible for the abnormal cell functioning in the so-called polyglutamine diseases. To evaluate to what extent the ability of polyglutamine sequences to recruit other proteins into the intracellular aggregates depends on the composition of the aggregating peptide, we analysed the co-aggregation properties of the N-terminal fragment of huntingtin fused with unrelated non-aggregating and/or self-aggregating peptides. We show that the ability of the mutated N-terminal huntingtin fragment to sequester non-related proteins can be significantly increased by fusion with the non-aggregating reporter protein [GFP (green fluorescence protein)]. By contrast, fusion with the self-aggregating C-terminal fragment of the CFTR (cystic fibrosis transmembrane conductance regulator) dramatically reduces the sequestration of related non-fused huntingtin fragments. We also demonstrate that the co-aggregation of different non-fused N-terminal huntingtin fragments depends on their length, with long fragments of the wild-type huntingtin not only excluded from the nuclear inclusions, but also very inefficiently sequestered into the cytoplasmic aggregates formed by the short fragments of mutant protein. Additionally, our results suggest that atypical intracellular aggregation patterns, which include unusual distribution and/or morphology of protein aggregates, are associated with altered ability of accumulating proteins to co-aggregate with other peptides.