RAD23 Control of ALS phenotypes

摘要 受损的、错误折叠的和易于聚集的蛋白质在 神经退行性疾病反映了细胞蛋白质稳态的破坏(或 “蛋白质代谢”)。蛋白质平衡是蛋白质合成和蛋白质降解的适当平衡 这是最佳细胞功能所必需的。错折叠蛋白质及其相互作用的鉴定 靶向主要的降解途径(即蛋白酶体或自噬途径) 都是高度受监管的过程。这一过程中的一个关键蛋白质是RAD23。RAD23促进 一些蛋白质的降解，并稳定其他蛋白质的细胞水平。这一机制 这些截然相反的操作背后的原因尚不清楚。有趣的是，烧蚀 RAD23加速破坏几种致病、易聚集的突变蛋白 (即，多聚Q扩展的Aaxin3、TDP43、SOD)，并在各种模型中提供益处 系统。我们假设RAD23将泛素化的错误折叠蛋白与 蛋白酶体，在此过程中，立体或变构抑制蛋白酶体功能。就这样， RAD23损害蛋白平衡。在具体目标#1中，我们将使用成像和生化 测试RAD23作用这一机制的方法。在ALS的体外和线虫模型中， RAD23的缺失是促进健康的--在小鼠模型中是否如此尚不清楚。 哺乳动物有两种RAD23亚型，即rad23A和rad23B。在具体目标2-4中，我们将使用基因 和反义低聚物技术，以消融和/或击倒RAD23A和/或RAD23B 几种肌萎缩侧索硬化症的小鼠模型。我们将全面审问损失的影响 RAD23A/B对小鼠存活、行为学和生化的影响。这些项目的顺利完成 这项研究有可能转化为临床治疗学。

Abstract The accumulation of damaged, misfolded and aggregation-prone proteins in neurodegenerative diseases reflects corruption of cellular protein homeostasis (or “proteostasis”). Proteostasis is the proper balance of protein synthesis and protein degradation that is required for optimal cellular functioning. The identification of misfolded proteins and their targeting to the major degradative pathways (i.e., the proteasome or the autophagy pathway) are highly regulated processes. A key protein in this process is RAD23. RAD23 promotes the degradation of some proteins and stabilizes cellular levels of other proteins. The mechanism underlying these diametrically opposed operations is not understood. Interestingly, ablation of rad23 accelerates the destruction several disease-causing, aggregation-prone mutated proteins (i.e., polyQ expanded Ataxin3, TDP43, SOD) and confers benefits in a variety of model systems. We hypothesize that RAD23 bridges ubiquitinated misfolded proteins with the proteasome and in doing so, sterically or allosterically inhibits proteasome function. In this way, RAD23 impairs proteostasis. In specific aim #1, we will use imaging and biochemical approaches to test this mechanism of RAD23 action. In in vitro and C.elegans models of ALS, loss of RAD23 is health promoting – whether this is true in mouse models is unknown. Mammals have 2 rad23 isoforms, rad23A and rad23B. In specific aims 2-4, we will use genetic and anti-sense oligomer technology to ablate and/or knockdown rad23A, rad23B or both in several mouse models of ALS. We will comprehensively interrogate the effects of loss of rad23A/B on mouse survival, behavior and biochemistry. The successful completion of these studies has the potential to be translated into clinical therapeutics.