RAD23 Control of ALS phenotypes

摘要 受损的、错误折叠的和易聚集的蛋白质在细胞中的积累， 神经退行性疾病反映了细胞蛋白质稳态的破坏（或 “蛋白质稳态”）。蛋白质稳态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。错误折叠蛋白的鉴定及其应用 靶向主要降解途径（即，蛋白酶体或自噬途径） 都是高度规范的过程这个过程中的一个关键蛋白是RAD 23。RAD 23促进了 降解某些蛋白质并稳定其他蛋白质的细胞水平。机制 这些截然相反的操作的基础是不理解的。有趣的是， rad 23加速了几种致病的、易于聚集的突变蛋白的破坏 (i.e., polyQ扩展了Ataxin 3、TDP 43、SOD），并在多种模型中提供益处 系统.我们假设RAD 23将泛素化的错误折叠蛋白与 蛋白酶体，并且在这样做时，空间或变构地抑制蛋白酶体功能。通过这种方式， RAD 23损害蛋白质稳态。在具体目标#1中，我们将使用成像和生化技术， 方法来测试RAD 23作用的这种机制。在ALS的体外和秀丽隐杆线虫模型中， RAD 23的丢失是健康促进的-这在小鼠模型中是否正确尚不清楚。 哺乳动物有2种rad 23亚型，rad 23 A和rad 23 B。在具体目标2-4中，我们将使用遗传 和反义寡聚体技术，以消融和/或敲低 几种ALS小鼠模型。我们将全面询问损失的影响， rad 23 A/B对小鼠存活、行为和生物化学的影响。成功完成这些 研究有可能转化为临床治疗。

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.