Caspase-mediated nuclear pore complex trimming in myogenesis and muscular dystrophies

项目摘要/摘要 半胱氨酸天冬氨酸氨基转移酶是一组蛋白水解酶，因其在细胞凋亡中的破坏性作用而广为人知。而他们的 激活通常等同于细胞死亡，但在骨骼肌中，这并不成立。例如，在 在肌源性分化过程中，半胱氨酸天冬氨酸氨基转移酶以一种短暂的、可调节的、可逆的方式被激活。这些 蛋白水解酶也可以在Duchenne或四肢带状肌营养不良症中被慢性激活。尽管如此，非常 关于半胱氨酸天冬氨酸酶在肌肉形成和退变中的非凋亡性作用，人们知之甚少。通过专注于 Caspase介导的核孔复合体(NPC)的修剪，这个K01项目将阐明如何亚致死 半胱氨酸酶带来了如此截然不同的结果。半胱氨酸天冬氨酸氨基转移酶可以降解鼻咽癌的四个末端亚基， 损害核出口，并捕获几种含有核出口信号的蛋白质，其中许多具有 基因组的调节功能。在目标1中，含有NES的蛋白质在核中积累 将以公正的方式确定肌肉发生和驱动基因组重组。此外，还有一个重点突出的 将进行一项研究，以了解FAK，一种含有NES的焦点黏附蛋白，其双重功能是 细胞核中的转录辅助因子，与甲基CpG结合蛋白Mbd2相互作用，抑制生肌 基因。在目标2中，将评估caspase介导的营养不良肌肉中NPC的修剪。鉴于这种谦虚的态度 内质网应激源激活caspase足以导致鼻咽癌修剪和核出口关闭 肌管，营养不良肌肉中的鼻咽癌也会发生类似的改变和功能障碍。因此，蛋白质组- 将进行广泛的搜索，以确定营养不良患者核水平异常高的蛋白质 肌核并有可能导致基因组失调。 简而言之，通过剖析caspase-npc-核输出轴的拮抗多效性，本提案 旨在为促进两种健康人群肌肉健康的新治疗方法提供基础 个人和肌营养不良症患者。这项研究结合了马丁·赫策实验室(The Martin Hetzer Lab)的专业知识 索尔克研究所)和洛伦佐·普里实验室(Sanford-Burnham-Prebys)的肌肉生物学研究。Dr。 Cho的长期目标是领导一个研究小组，研究核蛋白质组和蛋白质酶在 肌发生和肌营养不良。K01奖将为他提供稳定、人际交往的机会 有信心发展成为肌肉生物学领域的年轻领导者，精通简化论者和 系统方法。

PROJECT SUMMARY/ABSTRACT Caspases are a group of proteases most well known for their destructive role in apoptosis. While their activation is often equated with cell death, in skeletal muscles, this does not hold true. For example, during myogenic differentiation, caspases are activated in a transient, regulated, and reversible manner. These proteases can also be activated chronically in Duchenne or limb-girdle muscular dystrophies. Nevertheless, very little is known about the non-apoptotic roles of caspases in muscle formation and degeneration. By focusing on caspase-mediated trimming of the nuclear pore complex (NPC), this K01 project will elucidate how sublethal caspases bring about such contrasting outcomes. Caspases can proteolyze four distal subunits of the NPC, impair nuclear export, and entrap several NES (nuclear export signal)-containing proteins, many of which have genome regulatory functions. In Aim 1, NES-containing proteins that accumulate in the nucleus during myogenesis and drive genome reconfiguration will be identified in an unbiased manner. In addition, a focused study will be conducted to understand how FAK, an NES-containing focal adhesion protein that doubles as a transcription cofactor in the nucleus, interacts with MBD2, a methyl CpG-binding protein, to de-repress myogenic genes. In Aim 2, caspase-mediated NPC trimming in dystrophic muscles will be assessed. Given that modest activation of caspases by ER stressors is sufficient to cause NPC trimming and nuclear export shutdown in myotubes, the NPC in dystrophic muscles will be similarly modified and dysfunctional. Therefore, a proteome- wide search will be performed to identify proteins whose nuclear levels are abnormally high in dystrophic myonuclei and have potential to induce genome dysregulation. In short, by dissecting the antagonistic pleiotropy of the caspase-NPC-nuclear export axis, this proposal aims to provide a foundation for new therapeutic approaches that promote muscular health in both healthy individuals and muscular dystrophy patients. This research combines the expertise of the Martin Hetzer lab (the Salk Institute) in the NPC and that of the Lorenzo Puri lab (Sanford-Burnham-Prebys) in muscle biology. Dr. Cho’s long-term goal is to lead a research group that studies nuclear proteome and proteases in the context of myogenesis and muscular dystrophies. K01 award will provide him the stability, networking opportunity, and confidence to develop into a young leader in the field of muscle biology who is proficient in both reductionist and systems approaches.