Tubulin modifications and cytoskeletal alterations in aging

项目摘要 值得注意的是，我们对导致细胞骨架改变和表型改变的机制的理解， 这些变化对衰老细胞的影响仍然非常有限。我们已经确定并开始描述关键 维持正常核形态所需的蛋白质，包括两种新蛋白质（LRRC 49和C11 orf 49） 其组装成微管蛋白聚谷氨酰胺酶（TPG）复合物。我们最近发现每种蛋白质 调节微管蛋白谷氨酰化和核形态，这些基因的消融改变后， 微管蛋白的翻译修饰（PTM）、细胞骨架网络和核形状。因为类似的 细胞骨架和核缺陷也观察到在细胞中获得的患者与过早老化 综合征，Hutchinson-Gilford早衰综合征（HGPS），这促使我们假设， PTM和微管网络的缺陷可能与衰老有关。此外，据了解， SUN 1是LINC（核骨架和细胞骨架连接体）复合物的一种组分， 细胞骨架和核骨架在正常和过早衰老期间发生改变。但不清楚 SUN 1水平的改变是衰老的原因还是结果。我们将追求两个目标，这两个目标将联合收割机结合起来 生物化学和细胞生物学方法，以（1）研究微管网络缺陷的全局作用 以及在生理老化过程中和在早衰细胞中微管蛋白谷氨酰化和SUN 1水平的改变，以及 (2)确定与正常和过早衰老相关的缺陷如何转化为全基因组变化 在染色质拓扑学中。在这里，我们将特别关注TPG和SUN 1蛋白如何全局调节 衰老过程中微管网络和核组装。我们的研究将解决基本问题 与SUN 1和微管蛋白修饰在核形状变化和生理和病理变化中的作用有关。 衰老的病理模型，我们的研究将确定这些变化是否是一个原因， 老化的后果。我们的研究还将提供深入了解染色质拓扑结构的变化持续 通过正常或病理机制老化的细胞。

Project Summary Remarkably, our understanding of the mechanisms that lead to cytoskeletal alterations and the phenotypic impact of these alterations in aging cells remains very limited. We have identified and begun characterizing key proteins required to maintain normal nuclear morphology, including two novel proteins (LRRC49 and C11orf49) that assemble into a tubulin poly-glutamylase (TPG) complex. We have recently shown that each protein regulates both tubulin glutamylation and nuclear morphology, and ablation of these genes alters post- translational modifications (PTM) of tubulin, cytoskeletal networks, and nuclear shape. Since similar cytoskeletal and nuclear defects are also observed in cells obtained from patients with the premature aging syndrome, Hutchinson-Gilford progeria syndrome (HGPS), this prompted us to hypothesize that specific defects in PTMs and microtubule networks could be associated with aging. Furthermore, it is known that levels of SUN1, a component of the LINC (Linkers of Nucleoskeleton and Cytoskeleton) complex that connects the cytoskeleton and the nucleoskeleton, are altered during normal and premature aging. However, it is unknown whether altered SUN1 levels are a cause or consequence of aging. We will pursue two Aims that combine biochemical and cell biological approaches to (1) investigate a global role for defects in microtubule networks and alterations in tubulin glutamylation and SUN1 levels during physiological aging and in progeroid cells, and (2) identify how defects associated with normal and premature aging are translated into genome-wide changes in chromatin topology. Here, we will specifically focus on how the TPG and SUN1 protein globally regulate microtubule networks and nuclear assembly during aging. Our studies will address fundamental questions related to the role of SUN1 and tubulin modifications in nuclear shape changes and in physiological and pathological models of aging, and our studies will determine whether these alterations are a cause or consequence of aging. Our studies will also provide insights into the changes in chromatin topology sustained by cells that age through normal or pathological mechanisms.