Prothymosin-α Interacts with Mutant Huntingtin and Suppresses Its Cytotoxicity in Cell Culture
Prothymosin-α Interacts with Mutant Huntingtin and Suppresses Its Cytotoxicity in Cell Culture
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DOI：
10.1074/jbc.m111.294280
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发表时间：
2012-01-06
影响因子：
4.8
通讯作者：
Wang, Hongmin
中科院分区：
文献类型：
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作者：
Dong, Gaofeng;Callegari, Eduardo A.;Wang, Hongmin
亨廷顿病（HD）是一种致命的神经退行性疾病，由亨廷顿（Htt）蛋白中的多聚谷氨酰胺束的延长引起。尽管付出了相当大的努力，但迄今为止还没有治愈或治疗这种疾病的方法。使用串联亲和纯化的方法，我们最近发现，胸腺素原-α（ProT α），一个小的高度酸性蛋白质，与突变型Htt（mHtt）相互作用。免疫共沉淀和谷胱甘肽S-转移酶（GST）下拉试验证实了这一点。在表达N-末端mHtt片段的非神经元和神经元细胞模型中，ProT α的过表达显著降低了mHtt诱导的细胞毒性，而在细胞中敲低ProT α表达增强了mHtt引起的细胞死亡。删除ProT α的中心酸性结构域不仅消除了其与mHtt的相互作用，而且还消除了其对mHtt引起的细胞毒性的保护作用。此外，ProT α的过表达抑制caspase-3的活化，但增强mHtt的聚集。此外，当添加到表达mHtt的培养细胞中时，纯化的重组ProT α蛋白不仅进入细胞，而且还显著抑制mHtt引起的细胞毒性。总之，这些数据表明，ProT α可能是治疗HD和其他多聚谷氨酰胺扩增疾病的新的治疗靶点。
Huntington disease (HD), a fatal neurodegenerative disorder, is caused by a lengthening of the polyglutamine tract in the huntingtin (Htt) protein. Despite considerable effort, thus far there is no cure or treatment available for the disorder. Using the approach of tandem affinity purification we recently discovered that prothymosin-alpha (ProT alpha), a small highly acidic protein, interacts with mutant Htt (mHtt). This was confirmed by co-immunoprecipitation and a glutathione S-transferase (GST) pull-down assay. Overexpression of ProT alpha remarkably reduced mHtt-induced cytotoxicity in both non-neuronal and neuronal cell models expressing N-terminal mHtt fragments, whereas knockdown of ProT alpha expression in the cells enhanced mHtt-caused cell death. Deletion of the central acidic domain of ProT alpha abolished not only its interaction with mHtt but also its protective effect on mHtt-caused cytotoxicity. Additionally, overexpression of ProT alpha inhibited caspase-3 activation but enhanced aggregation of mHtt. Furthermore, when added to cultured cells expressing mHtt, the purified recombinant ProT alpha protein not only entered the cells but it also significantly suppressed the mHtt-caused cytotoxicity. Taken together, these data suggest that ProT alpha might be a novel therapeutic target for treating HD and other polyglutamine expansion disorders.