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的机制和表型的理解 这些变化对老化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，包括两个新的蛋白质(LRRC49和C11orf49) 它们组装成微管蛋白聚谷氨酰胺酶(TPG)复合体。我们最近已经证明，每种蛋白质 同时调节微管蛋白谷氨酸化和核形态，而这些基因的去除会改变后 微管蛋白、细胞骨架网络和核形状的翻译修饰(PTM)。由于相似 在早衰患者的细胞中也观察到细胞骨架和核的缺陷。 综合症，Hutchinson-Gilford早衰症(HGPS)，这促使我们假设 PTMS和微管网络的缺陷可能与衰老有关。此外，已知的水平 SUN1是LINC(核骨架和细胞骨架的连接物)复合体的一个组成部分，连接着 细胞骨架和核骨架在正常和过早衰老过程中会发生变化。然而，它是未知的 SUN1水平的改变是衰老的原因还是结果。我们将追求两个目标相结合 生化和细胞生物学方法：(1)研究微管网络中缺陷的全球作用 以及生理性衰老和孕激素细胞中微管蛋白谷氨化和SUN1水平的变化，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的变化 在染色质拓扑中。在这里，我们将特别关注TPG和SUN1蛋白如何在全球范围内调节 衰老过程中的微管网络和核组装。我们的研究将解决基本问题 与SUN1和微管蛋白修饰在核形状变化中的作用以及在生理和 衰老的病理模型，我们的研究将确定这些变化是原因还是 衰老的后果。我们的研究还将为染色质拓扑结构的持续变化提供见解 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.