Screening of compounds for protecting polyglutamine diseases

筛选预防多聚谷氨酰胺疾病的化合物

基本信息

批准号：
13557058
负责人：
NUKINA Nobuyuki
金额：
$ 7.68万
依托单位：
RIKEN
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13557058/
关键词：
Polyglutamine CAG repeat Aggregate Cell death Myoglobin

项目摘要

A major hallmark of the polyglutamine (pQ) diseases is the formation of pQ inclusions. Recently, misfolding has come to be considered one of the primary factors for pQ protein aggregation, although, the nature of misfolding and the relationship between misfolding and ubiquitination of the expanded pQ protein is not yet known. By using ataxin-3, the defective gene product of SCA3/MJD, we demonstrated that the cellular toxicity of a pQ protein is directly proportional to the length of the glutamine repeats and inversely dependent on the size of the corresponding protein. The pQ expansion and truncation enhance the reactivity of 1C2 antibody (specific to expanded pQ), chaperone association and ubiquitination, suggesting that pQ expansion and protein truncation enhance the protein misfolding.The protein misfolding induced by pQ expansion was further investigated with our molecular model system using mutant myoglobin which is inserted different size of pQ. Polyglutamine stretches form intra … More molecular β-sheets when pQ expanded and they form intermolecular β-sheets and amyloid fibrils after certain incubation time. The surface of the mutant myoglobin with expanded pQ was partially unfolded and destabilized. We also investigated the early phase of fibrillization of the mutant myoglobin in which 35 or 50 glutamine repeats are inserted. Small-angle X-ray scattering and electron microscopic studies revealed that the expansion of pQ to 50 repeats induced the formation of quasi-aggregate in the earliest stage of the protein fibrillization. We found that β-sheets of pQ in quasi-aggregate were exposed on the surface and were not regularly oriented, as opposed to those in amyloid fibril. X-ray diffraction analysis indicated that the expansion of glutamine repeat did not show substantial effects on the β-sheet structure of pQ in fibril. Since the expansion of glutanine repeat in certain proteins is responsible for pQ diseases, the present study suggests that the condensed and non-oriented β-sheets exposed on the surface of quasi-aggregate, rather than the regularly aligned β-sheets in fibrils, are closely involved in recruitment of various functional proteins into aggregates, leading to the cellular dysfunction that causes pQ diseases. Thus, the quasi-aggregate form also should be targeted to the therapeutic strategy for pQ diseases.Base on those structural change, we searched for compounds to stabilize the molecule with expanded polyglutamine and found some effective compounds. Less

聚谷氨酰胺（PQ）疾病的主要标志是PQ夹杂物的形成。最近，错误折叠已被认为是PQ蛋白聚集的主要因素之一，尽管尚不清楚折叠折叠的性质以及扩展的PQ蛋白的错误折叠和泛素化之间的关系。通过使用SCA3/MJD的有缺陷的基因产物Ataxin-3，我们证明了PQ蛋白的细胞毒性与谷氨酰胺重复序列的长度成正比，并取决于相应蛋白质的大小。 PQ的扩展和截断增强了1C2抗体（特异于扩展的PQ），伴侣关联和泛素化的反应性，这表明PQ膨胀和蛋白质截断增强了蛋白质错误折叠的蛋白质折叠。使用PQ扩展诱导的蛋白质折叠率使用PQ扩展诱导的蛋白质折叠率使用了我们的分子模型系统，该蛋白使用PQ扩展使用了PER，使用了PERTINANS MOTICLANT MONICLOB蛋白。聚谷氨酰胺在PQ扩展时会伸展……更多的分子β-折叠，并在一定的孵育时间后形成分子间β-折叠和淀粉样蛋白纤维。具有扩展PQ的突变体肌红蛋白的表面被部分展开和不稳定。我们还研究了突变体肌球蛋白的纤维化的早期阶段，其中插入了35或50个谷氨酰胺重复。小角度的X射线散射和电子显微镜研究表明，PQ向50个重复的膨胀诱导了蛋白质纤维化最早的准聚集酸盐的形成。我们发现，与淀粉样蛋白原纤维中的PQ相比，与淀粉样蛋白原纤维中的PQ相比，PQ的β-折叠暴露在表面上，并未定期定向。 X射线衍射分析表明，谷氨酰胺重复的膨胀对原纤维中PQ的β-折叠结构没有实质性影响。 Since the expansion of glutanine repeat in certain proteins is responsible for pQ diseases, the present Study suggests that the condensed and non-oriented β-sheets exposed on the surface of quasi-aggregate, rather than the regularly aligned β-sheets in fibrils, are closely involved in recruiting of various functional proteins into aggregates, leading to the cellular dysfunction that causes pQ diseases.这也应针对PQ疾病的治疗策略。在这些结构变化上，我们搜索化合物以稳定分子，并发现了一些有效的化合物。较少的