Nollen Ellen A A, Garcia Susana M, van Haaften Gijs, Kim Soojin, Chavez Alejandro, Morimoto Richard I, Plasterk Ronald H A
Division of Functional Genomics, Hubrecht Laboratories/Netherlands Institute for Developmental Biology, 3584 CT Utrecht, The Netherlands.
Proc Natl Acad Sci U S A. 2004 Apr 27;101(17):6403-8. doi: 10.1073/pnas.0307697101. Epub 2004 Apr 14.
Protein misfolding and the formation of aggregates are increasingly recognized components of the pathology of human genetic disease and hallmarks of many neurodegenerative disorders. As exemplified by polyglutamine diseases, the propensity for protein misfolding is associated with the length of polyglutamine expansions and age-dependent changes in protein-folding homeostasis, suggesting a critical role for a protein homeostatic buffer. To identify the complement of protein factors that protects cells against the formation of protein aggregates, we tested transgenic Caenorhabditis elegans strains expressing polyglutamine expansion yellow fluorescent protein fusion proteins at the threshold length associated with the age-dependent appearance of protein aggregation. We used genome-wide RNA interference to identify genes that, when suppressed, resulted in the premature appearance of protein aggregates. Our screen identified 186 genes corresponding to five principal classes of polyglutamine regulators: genes involved in RNA metabolism, protein synthesis, protein folding, and protein degradation; and those involved in protein trafficking. We propose that each of these classes represents a molecular machine collectively comprising the protein homeostatic buffer that responds to the expression of damaged proteins to prevent their misfolding and aggregation.
蛋白质错误折叠和聚集体的形成日益被认为是人类遗传疾病病理学的组成部分以及许多神经退行性疾病的标志。以多聚谷氨酰胺疾病为例，蛋白质错误折叠的倾向与多聚谷氨酰胺扩展的长度以及蛋白质折叠稳态的年龄依赖性变化相关，这表明蛋白质稳态缓冲器起着关键作用。为了确定保护细胞免受蛋白质聚集体形成影响的蛋白质因子的补充物，我们测试了在与蛋白质聚集的年龄依赖性出现相关的阈值长度下表达多聚谷氨酰胺扩展黄色荧光蛋白融合蛋白的转基因秀丽隐杆线虫菌株。我们使用全基因组RNA干扰来鉴定那些被抑制时会导致蛋白质聚集体过早出现的基因。我们的筛选鉴定出了186个基因，它们对应于多聚谷氨酰胺调节因子的五个主要类别：参与RNA代谢、蛋白质合成、蛋白质折叠和蛋白质降解的基因；以及参与蛋白质运输的基因。我们提出，这些类别中的每一个都代表一种分子机器，它们共同构成了蛋白质稳态缓冲器，该缓冲器对受损蛋白质的表达做出反应，以防止其错误折叠和聚集。
