Dynamic Glycosylation Governs the Vertebrate COPII Protein Trafficking Pathway
Dynamic Glycosylation Governs the Vertebrate COPII Protein Trafficking Pathway
复制标题
DOI：
10.1021/acs.biochem.7b00870
复制
发表时间：
2018-01-09
期刊：
影响因子：
2.9
通讯作者：
Boyce, Michael
中科院分区：
文献类型：
--
作者：
Cox, Nathan J.;Unlu, Gokhan;Boyce, Michael
介导内质网分泌货物运输的COPII外壳复合物是亚细胞蛋白靶向的关键控制点。由于错误导向的蛋白质无法发挥作用，COPII的蛋白质分选对于建立和维持正常的细胞和组织稳态至关重要。事实上，COPE基因的突变会导致一系列人类疾病，包括以胶原转运缺陷、颅面异常和骨骼畸形为特征的颅骨-透镜体-缝合线发育不良（CLSD）。要了解COPII通路在正常细胞生理学中的作用，并设计出新的治疗方法，需要详细了解COPII通路。然而，对于脊椎动物如何动态调节COPII活性以响应发育、代谢或病理线索，我们知之甚少。一些COPE蛋白被O-linked β - n -乙酰氨基葡萄糖（O-GlcNAc）修饰，这是一种细胞内蛋白糖基化的动态形式，但这些修饰的生化和功能影响尚不清楚。在这里，我们使用化学、生化、细胞和遗传方法的组合来证明COPE蛋白的位点特异性o - glcn酰化介导它们之间的蛋白质相互作用并调节货物分泌。特别是，我们发现SEC23A的单个o - glcn酰化位点（COPII的重要成分）在人类细胞和脊椎动物发育中发挥作用是必需的，因为这些位点的突变会损害SEC23A依赖的体内胶原运输和斑马鱼CLSD模型中的骨骼形成。我们的研究结果表明，O-GlcNAc在脊椎动物cope依赖的转运途径中是一个保守而关键的调控修饰。
The COPII coat complex, which mediates secretory cargo trafficking from the endoplasmic reticulum, is a key control point for subcellular protein targeting. Because misdirected proteins cannot function, protein sorting by COPII is critical for establishing and maintaining normal cell and tissue homeostasis. Indeed, mutations in COPE genes cause a range of human pathologies, including cranio-lenticulo-sutural dysplasia (CLSD), which is characterized by collagen trafficking defects, craniofacial abnormalities, and skeletal dysmorphology. Detailed knowledge of the COPII pathway is required to understand its role in normal cell physiology and to devise new treatments for disorders in which it is disrupted. However, little is known about how vertebrates dynamically regulate COPII activity in response to developmental, metabolic, or pathological cues. Several COPE proteins are modified by O-linked beta-N-acetylglucosamine (O-GlcNAc), a dynamic form of intracellular protein glycosylation, but the biochemical and functional effects of these modifications remain unclear. Here, we use a combination of chemical, biochemical, cellular, and genetic approaches to demonstrate that site specific O-GlcNAcylation of COPE proteins mediates their protein protein interactions and modulates cargo secretion. In particular, we show that individual O-GlcNAcylation sites of SEC23A, an essential COPII component, are required for its function in human cells and vertebrate development, because mutation of these sites impairs SEC23A-dependent in vivo collagen trafficking and skeletogenesis in a zebrafish model of CLSD. Our results indicate that O-GlcNAc is a conserved and critical regulatory modification in the vertebrate COPE-dependent trafficking pathway.