Recognition and removal of organelle damage at the endoplasmic reticulum membrane

内质网膜细胞器损伤的识别和去除

• 批准号: 455429207
• 负责人: Professor Dr. Sebastian Schuck
• 金额: --
• 依托单位: Biochemie-Zentrum (BZH)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/455429207?language=en
• 关键词: Recognition; removal; organelle; damage; endoplasmic

Cells employ numerous quality control mechanisms to ensure organelle integrity. Compared to quality control in the cytosol, quality control of membrane-enclosed organelles poses unique challenges. Organelle membranes present barriers for the detection and elimination of damaged proteins, yet these barriers need to be maintained at all times. The endoplasmic reticulum (ER) is a central protein folding compartment liable to the accumulation of misfolded proteins. In earlier work, we focused on two related quality control mechanisms in yeast that respond to ER stress. First, we showed that selective microautophagy of ER (micro-ER-phagy) involves the formation of multi-lamellar ER whorls that are degraded in lysosomes, presumably to remove ER damage. We recently found that ESCRT proteins are essential for micro-ER-phagy because they mediate lysosomal membrane fission to complete microautophagy of whorls. We also found that the control of protein entry into whorls likely is critical for the selectivity of micro-ER-phagy. Second, we discovered that ER stress triggers a striking recruitment of ESCRT proteins to morphologically aberrant ER subdomains. We call this mechanism REMED (Recruitment of ESCRT Machinery to sites of ER Damage). We hypothesize that REMED repairs ER membrane damage and cooperates with micro-ER-phagy. Here, we propose to investigate the mechanisms of micro-ER-phagy and REMED, and explore the functional links between them. In Aim 1, we will apply proteomic approaches to determine the protein contents of ER whorls and thus define cargo selectivity. In Aim 2, we will elucidate the mechanism of REMED through yeast genetic screens and cell biological experiments, and ask whether REMED exists in human cells. In Aim 3, we will use genetic interaction studies and functional assays in yeast to understand the physiological roles of micro-ER-phagy and REMED. This project will yield new insight into ER damage recognition and removal. Moreover, given that manipulating ER quality control promises health benefits, our research may identify new therapeutic approaches.

细胞采用多种质量控制机制来确保细胞器的完整性。与细胞质溶胶的质量控制相比，膜封闭细胞器的质量控制面临着独特的挑战。细胞器膜为检测和消除受损蛋白质提供屏障，但这些屏障需要始终保持。内质网（ER）是一个中心的蛋白质折叠室，容易积聚错误折叠的蛋白质。在早期的工作中，我们关注酵母中响应内质网应激的两种相关的质量控制机制。首先，我们发现内质网的选择性微自噬（微内质网吞噬）涉及多层内质网螺旋的形成，这些内质网螺旋在溶酶体中降解，可能是为了消除内质网损伤。我们最近发现ESCRT蛋白对微er吞噬至关重要，因为它们介导溶酶体膜裂变以完成螺旋的微自噬。我们还发现，蛋白质进入螺旋的控制可能对微er吞噬的选择性至关重要。其次，我们发现内质网应激触发了ESCRT蛋白在形态学异常的内质网亚结构域的显著募集。我们称这种机制为REMED （ESCRT机械向内质网损伤部位的招募）。我们假设REMED修复内质网膜损伤并与微内质网吞噬协同作用。在此，我们拟探讨微er吞噬与REMED的机制，并探讨两者之间的功能联系。在目标1中，我们将应用蛋白质组学方法来确定内质网螺旋的蛋白质含量，从而定义货物选择性。在Aim 2中，我们将通过酵母遗传筛选和细胞生物学实验来阐明REMED的机制，并探讨REMED是否存在于人类细胞中。在Aim 3中，我们将使用酵母的遗传相互作用研究和功能分析来了解微er吞噬和REMED的生理作用。该项目将对内质网损伤识别和清除产生新的见解。此外，考虑到操纵ER质量控制承诺健康益处，我们的研究可能会确定新的治疗方法。