Regulation of developmental signaling pathways by glycosylation and deglycosylation

到目前为止，所研究的所有细胞类型的大多数分泌和细胞表面蛋白都是糖基化的，即 装饰着糖分子。这些碳水化合物修饰起着不同的结构和功能作用。 在生物体中，并参与动物的正常发育和生理。各种不同基因的突变 糖基化机制的组成部分已被证明会导致100多种人类疾病， 影响到几乎所有的器官系统。然而，在动物蛋白质上发现的糖链结构是复杂的 异质性，每一种形式的糖基化都可以在数十到数千种蛋白质上找到。因此，它是 难以理解在糖基化中观察到的表型的分子机制 精神错乱。我们研究的长期目标是了解碳水化合物修饰是如何调节 动物发育，利用这一知识洞察人类糖基化的病理生理学 疾病，并为新的治疗方法建立框架，以治疗由 影响蛋白质糖基化的突变。我们主要感兴趣的领域是糖生物学和 以及发育信号通路，这是进化上保守的少量细胞间信号通路 广泛用于动物胚胎发育和成年维持的信号机制。一 我们的主要研究重点是连接到Notch蛋白上的O-连接的多糖，它构成了受体 这是动物最重要的发育信号通路之一。我们之前已经将其描述为 木糖-葡萄糖-O-葡聚糖加成相关酶在果蝇调控中的作用 发展和陷波信令。我们还研究了第一种酶在这个途径中的作用。 (POGLUT1)，并将POGLUT1与两种人类疾病联系起来，一种是发育障碍，另一种是 肌肉营养不良症。在目前的应用中，我们建议表征酶的作用 在哺乳动物发育和Notch信号通路中位于POGLUT1下游。此外，我们还发现， 参与从蛋白质中去除N-连接的糖链的酶调节另一个主要的信号通路( 骨形态发生蛋白或骨形态发生蛋白途径)在果蝇中以组织特异性的方式表达。这种酶的突变 (NGLY1)在人类患者中引起多系统发育障碍，但 疾病尚不为人所知。我们建议确定潜在的分子机制的调节 NGLY1在果蝇中的BMP途径，并确定哺乳动物BMP信号的哪些方面受到调控 通过这种酶。除了提供对糖基化在主要信号调节中的作用的洞察 途径，这些项目有可能建立新的工具来改变Notch和BMP的活性 在疾病背景下和再生医学中的信号。

The majority of secreted and cell-surface proteins of all cell types studied so far are glycosylated, i.e. decorated with sugar molecules. These carbohydrate modifications play diverse structural and functional roles in organisms, and are involved in proper animal development and physiology. Mutations in various components of the glycosylation machinery have been shown to cause more than 100 human diseases, affecting virtually all organ systems. However, the glycan structures found on animal proteins are complex and heterogeneous, and each form of glycosylation can be found on tens to thousands of proteins. Therefore, it is difficult to understand the molecular mechanisms underlying the phenotypes observed in glycosylation disorders. The long-term goals of our research are to understand how carbohydrate modifications regulate animal development, to use this knowledge to provide insight into the pathophysiology of human glycosylation disorders, and to establish frameworks for novel therapeutic approaches in diseases caused or impacted by mutations affecting protein glycosylation. Our primary area of interest is the intersection between glycobiology and developmental signaling pathways, which are a small number of evolutionarily conserved, intercellular signaling mechanisms broadly used during embryonic development and adult maintenance of animals. One major focus of our research is on O-linked glycans attached to Notch proteins, which constitute the receptors for one of the most important developmental signaling pathways in animals. We have previously characterized the role of the enzymes involved in the addition of xylose-glycose-O glycans in the regulation of Drosophila development and Notch signaling. We have also studied the role of the first enzyme in this pathway (POGLUT1) in mice, and have linked POGLUT1 to two human diseases, a developmental disorder and a muscular dystrophy. In the current application, we propose to characterize the role of the enzymes downstream of POGLUT1 in mammalian development and Notch signaling. Moreover, we have found that an enzyme involved in removing N-linked glycans from proteins regulates another major signaling pathway (the bone morphogenetic protein or BMP pathway) in flies in a tissue-specific manner. Mutations in this enzyme (NGLY1) cause a multi-system developmental disorder in human patients, but the pathophysiology of the disease is not known. We propose to determine the molecular mechanisms underlying the regulation of the BMP pathway by NGLY1 in flies, and to determine which aspects of mammalian BMP signaling are regulated by this enzyme. In addition to providing insight into the roles of glycosylation in the regulation of major signaling pathways, these projects have the potential to establish novel tools to alter the activity of Notch and BMP signaling in disease contexts and in regenerative medicine.