Modulation of ataxin-1 phosphorylation

描述（由申请人提供）： 脊髓小脑性共济失调1型（SCA 1）是由SCA 1编码的蛋白共济失调蛋白-1内的谷氨酰胺重复扩增引起的常染色体显性神经退行性疾病。突变型ataxin-1的亚细胞定位和沉积是SCA 1发病机制中的关键因素。控制这些事件的机制尚不清楚，然而，磷酸化是控制蛋白质定位和降解的一种手段。我们试图确定共济失调蛋白-1是否被磷酸化，并且已经表明野生型和突变型共济失调蛋白-1的丝氨酸776（S776）在体内和体外都被磷酸化。通过用丙氨酸取代该残基来防止其磷酸化，导致在细胞核中发现非致病性的突变蛋白。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，该测定法可用于筛选共济失调蛋白-1丝氨酸776磷酸化调节剂的化合物文库。这样的筛选将确定新的分子工具，以帮助阐明SCA 1发病机制。此外，鉴定的化合物将为开发SCA 1的治疗性治疗提供潜在的线索。已验证的先导化合物将用于开始使用SCA 1小鼠模型的临床前试验。

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.