Uncovering an Enzymatic Program that Drives Physiological and Pathological Amyloid Formation.

项目摘要 淀粉样蛋白是在各种蛋白质病中积累的富含β折叠的聚集体。这种相关性导致了 淀粉样蛋白与疾病状态的关联。然而，生物体利用淀粉样蛋白，而没有任何 明显的有害影响。这就引出了一个根本问题：细胞如何组装无毒的淀粉样蛋白 根据需要？我们的实验室发现了一个生理性淀粉样蛋白生成的诱导程序， 淀粉样体在研究这些富含淀粉样蛋白的固体状冷凝物时，我们发现， 末端核苷酸转移酶4 b（TENT 4 b）刺激淀粉样蛋白生成的液体向固体的转化 相变我们的初步结果表明，TENT催化异常长的富含poly（A）的尾部驱动 淀粉样变性这些低复杂性RNA分子作为线性聚阴离子辅因子， 淀粉样变性这种活性被降解加尾RNA的RNA外泌体抑制。除了 除了生理性淀粉样蛋白生成外，TENT还催化病理性淀粉样蛋白生成， 在阿尔茨海默病和帕金森病模型中的低聚中间体。RNA外泌体的消耗， 拮抗TENT，延迟这些疾病模型中与年龄相关的蛋白毒性。这些结果表明 以下是K99：R 00应用的假设：RNA加尾机制驱动淀粉样蛋白生成， 对抗有毒的低聚中间体。我们计划通过以下方式来验证这一假设：目标1-研究机制 驱动生理性淀粉样蛋白生成和Aim 2-测试这种机制是否能防止病理性淀粉样蛋白生成， 淀粉样蛋白毒性这项研究计划揭示了一个挑衅性的概念，即细胞拥有专门的酶 制造无毒的淀粉样蛋白，强调细胞淀粉样蛋白生成是一个积极控制的过程。的 细胞使用RNA主动控制蛋白质折叠桥无关的研究领域，并提供了新的 治疗淀粉样蛋白疾病的方法。

Project Summary Amyloids are β-sheet rich aggregates that accumulate in various proteinopathies. This correlation has led to the association of amyloids with the diseased state. However, organisms across biology utilize amyloids without any apparent detrimental effects. This raises the fundamental question; how do cells assemble non-toxic amyloids as needed? Our lab uncovered an inducible program of physiological amyloidogenesis that converts Nucleoli into Amyloid-bodies. While investigating these amyloid-enriched, solid-like condensates, we identified that Terminal End Nucleotidyltransferase 4b (TENT4b) stimulated the conversion of amyloidogenic liquid-to-solid phase transition. Our preliminary results indicate that TENTs catalyze unusually long poly(A)-rich tails to drive amyloidogenesis. These low-complexity RNA molecules act as linear polyanionic cofactors that stimulate amyloidogenesis. This activity is inhibited by the RNA exosome which degrades tailed RNA. In addition to physiological amyloidogenesis, TENTs also catalyze pathological amyloidogenesis which exhausts toxic oligomeric intermediates in Alzheimer’s and Parkinson’s disease models. Depletion of the RNA exosome that antagonizes TENTs, delays age-associated proteotoxicity in these disease models. These results suggest the following hypothesis for this K99:R00 application: The RNA tailing machinery drives amyloidogenesis to protect against toxic oligomeric intermediates. We plan to test this hypothesis by: Aim 1- investigating the mechanism that drives physiological amyloidogenesis and Aim 2- testing if this machinery protects against pathological amyloid toxicity. This research program reveals the provocative concept that cells possess enzymes dedicated to making non-toxic amyloids, highlighting that cellular amyloidogenesis is an actively controlled process. The cellular use of RNA to actively control protein folding bridges unrelated fields of research and offers new approaches to combat amyloid based disease.