Huntingtin and mutant SOD1 form aggregate structures with distinct molecular properties in human cells
Huntingtin and mutant SOD1 form aggregate structures with distinct molecular properties in human cells
复制标题
DOI：
10.1074/jbc.m509201200
复制
发表时间：
2006-02-17
影响因子：
4.8
通讯作者：
Morimoto, RI
中科院分区：
文献类型：
--
作者：
Matsumoto, G;Kim, S;Morimoto, RI
与神经退行性疾病相关的许多蛋白质的表达导致容易采用交替折叠状态的错误折叠种类的出现。在体内，这些表现为点状亚细胞结构，通常称为聚集体或包涵体。尽管将这些不同的蛋白质分组到一个共同的形态学类别中在概念上是有用的，但有一些建议认为聚集体不是均匀的，并且可以表现出一系列生物学特性。在这项研究中，我们使用动态成像分析活细胞的聚集和生长特性的突变亨廷顿蛋白与多聚谷氨酰胺的扩展或突变SOD 1（G85 R/G93 A），检查形成的聚集体结构和与其他细胞蛋白质的相互作用进行比较。使用双条件表达系统顺序表达荧光标记的蛋白质，我们表明，突变亨廷顿蛋白形成多个细胞内的细胞质和细胞核结构组成的致密核心不可接近新生的多肽所包围的表面，稳定地隔离某些转录因子和相互作用瞬时分子伴侣。相反，突变体SOD 1（G85 R/G93 A）形成了一个独特的聚集体结构，是多孔的，通过新生蛋白质扩散。这些结果表明，蛋白质聚集体不对应于一个单一的常见类别的亚细胞结构，而是可能有一个广泛的聚集体结构，也许每个对应于特定的疾病相关的蛋白质与不同的后果的生化状态的细胞。
Expression of many proteins associated with neurodegenerative disease results in the appearance of misfolded species that readily adopt alternate folded states. In vivo, these appear as punctated subcellular structures typically referred to as aggregates or inclusion bodies. Whereas groupings of these distinct proteins into a common morphological class have been useful conceptually, there is some suggestion that aggregates are not homogeneous and can exhibit a range of biological properties. In this study, we use dynamic imaging analysis of living cells to compare the aggregation and growth properties of mutant huntingtin with polyglutamine expansions or mutant SOD1 (G85R/G93A) to examine the formation of aggregate structures and interactions with other cellular proteins. Using a dual conditional expression system for sequential expression of fluorescence- tagged proteins, we show that mutant huntingtin forms multiple intracellular cytoplasmic and nuclear structures composed of a dense core inaccessible to nascent polypeptides surrounded by a surface that stably sequesters certain transcription factors and interacts transiently with molecular chaperones. In contrast, mutant SOD1 (G85R/G93A) forms a distinct aggregate structure that is porous, through which nascent proteins diffuse. These results reveal that protein aggregates do not correspond to a single common class of subcellular structures, and rather that there may be a wide range of aggregate structures, perhaps each corresponding to the specific disease-associated protein with distinct consequences on the biochemical state of the cell.