Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, Illinois, United States of America.
PLoS Genet. 2011 Dec;7(12):e1002438. doi: 10.1371/journal.pgen.1002438. Epub 2011 Dec 29.
A hallmark of diseases of protein conformation and aging is the appearance of protein aggregates associated with cellular toxicity. We posit that the functional properties of the proteostasis network (PN) protect the proteome from misfolding and combat the proteotoxic events leading to cellular pathology. In this study, we have identified new components of the proteostasis network that can suppress aggregation and proteotoxicity, by performing RNA interference (RNAi) genetic screens for multiple unrelated conformationally challenged cytoplasmic proteins expressed in Caenorhabditis elegans. We identified 88 suppressors of polyglutamine (polyQ) aggregation, of which 63 modifiers also suppressed aggregation of mutant SOD1(G93A). Of these, only 23 gene-modifiers suppressed aggregation and restored animal motility, revealing that aggregation and toxicity can be genetically uncoupled. Nine of these modifiers were shown to be effective in restoring the folding and function of multiple endogenous temperature-sensitive (TS) mutant proteins, of which five improved folding in a HSF-1-dependent manner, by inducing cytoplasmic chaperones. This triage screening strategy also identified a novel set of PN regulatory components that, by altering metabolic and RNA processing functions, establish alternate cellular environments not generally dependent on stress response activation and that are broadly protective against misfolded and aggregation-prone proteins.
蛋白质构象疾病和衰老的一个标志是与细胞毒性相关的蛋白质聚集物的出现。我们假设，质量控制系统（PN）的功能特性可以保护蛋白质组免受错误折叠，并对抗导致细胞病变的蛋白毒性事件。在这项研究中，我们通过在秀丽隐杆线虫中表达多种不相关的构象挑战细胞质蛋白的 RNA 干扰（RNAi）遗传筛选，鉴定了新的质量控制系统组件，这些组件可以抑制聚集和蛋白毒性。我们鉴定了 88 种聚谷氨酰胺（polyQ）聚集的抑制剂，其中 63 种调节剂也抑制突变型 SOD1（G93A）的聚集。在这些抑制剂中，只有 23 种基因调节剂既能抑制聚集又能恢复动物的运动能力，这表明聚集和毒性可以在遗传上解耦。其中 9 种调节剂被证明能有效地恢复多个内源性温度敏感（TS）突变蛋白的折叠和功能，其中 5 种通过诱导细胞质伴侣蛋白以 HSF-1 依赖的方式改善折叠。这种分类筛选策略还鉴定了一组新的 PN 调节成分，这些成分通过改变代谢和 RNA 处理功能，建立了替代的细胞环境，这些环境通常不依赖于应激反应的激活，并且对错误折叠和易于聚集的蛋白质具有广泛的保护作用。
