Modulation of ataxin-1 phosphorylation

描述（由申请人提供）： 脊髓小脑共济失调 1 型 (SCA1) 是一种常染色体显性神经退行性疾病，由 SCA1 编码的蛋白 ataxin-1 内谷氨酰胺重复序列的扩展引起。突变ataxin-1的亚细胞定位和沉积是SCA1发病机制的关键因素。控制这些事件的机制尚不清楚，但是，磷酸化是控制蛋白质定位和降解的一种手段。我们试图确定 ataxin-1 是否被磷酸化，并表明野生型和突变型 ataxin-1 的丝氨酸 776 (S776) 在体内和体外均被磷酸化。通过用丙氨酸取代该残基来防止该残基的磷酸化，会产生在细胞核中发现的非致病性突变蛋白。下面描述的研究的目标是开发一种基于细胞培养的测定法，可用于筛选 ataxin-1 丝氨酸 776 磷酸化调节剂的化合物库。这样的筛选将鉴定出新的分子工具来帮助阐明 SCA1 发病机制。此外，已鉴定的化合物将为 SCA1 治疗方法的开发提供潜在的线索。已验证的先导化合物将用于使用 SCA1 小鼠模型开始临床前测试。

DESCRIPTION (provided by applicant): Spinocerebeltar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disorder caused by the expansion of a glutamine repeat within the SCAl-encoded protein ataxin-l. The subcellular localization and deposition of mutant ataxin-1 is a critical factor in the pathogenesis of SCA1. The mechanism(s) that control these events are not understood, however, phosphorylation is a mean to control protein localization and degradation. We sought to determine if ataxin-1 is phosphorylated, and have shown that serine 776 (S776) of both wild type and mutant ataxin-1 is phosphorylated in vivo and in vitro. Preventing phosphorylation of this residue by replacing it with alanine results in a mutant protein found in the nucleus that is not pathogenic. The goal of the research described below is to develop a cell culture based assay that can be used to screen a compound library for modulators of ataxin-1 serine 776 phosphorylation. Such a screen will identify new molecular tools to aid in elucidating the mechanism of SCA1 pathogenesis. Moreover, identified compounds will provide potential leads toward the development of a therapeutic treatment for SCA1. Lead compounds that have been validated will be used to begin preclinical testing using a mouse model of SCA1.