Deciphering molecular details of cellular sugar transport and their roles in disease

摘要 糖，尤其是葡萄糖，不仅是几乎所有生物体中普遍存在的细胞燃料来源，而且 也是关键的代谢中间体，在其中活化的葡萄糖分子被运输到 内质网和高尔基体，用于糖基化蛋白质、脂类和其他有机化合物，作为 生物合成-分泌途径。为了完成这些多样化和本地化的功能，该机构 利用膜转运蛋白和通道将葡萄糖及其中间体 包裹在所有细胞和细胞器周围的不透膜的膜脂双层。次要的 在这一过程中，活跃的转运蛋白是关键的调节者。或者，与电压相关的阴离子 通道将葡萄糖中间体输送到线粒体，在那里它们进入TCA循环 三磷酸腺苷的生产。在它们对生理的基本功能中，这些蛋白质牵涉到许多 并被指定为药物化合物的靶标。 在题为《破译细胞糖运输和它们的分子细节》的父R35中 在疾病中的作用“我们的目标是描述几个转运蛋白家族的结构和功能 参与细胞糖和代谢物的运输。具体地说，我们想要研究葡萄糖钠 辅转运体(SGLT)、核苷酸糖转运体(NST)和唾液酸转运体(SIAT)以及 电压依赖阴离子通道(VDAC)。人SGLT是已知的治疗类风湿关节炎的靶点 II型糖尿病，但抑制的分子细节和异构体之间的功能差异是 不是很清楚。这在很大程度上是因为缺乏结构性信息。NST导入各种 活性糖化合物进入高尔基体和内质网，而SIAT用于输入清除的唾液酸 来自寄主的酸。真核生物和病原体NSTs之间的差异可以被利用来 治疗目的。然而，这个运输者家族在很大程度上仍然没有特征。VDAC是 代谢物通过线粒体膜外交换的中心媒介。尽管如此 它的关键作用、功能门控和底物运输的关键方面还不是很清楚。再说一遍， 我们希望，解决VDAC的其他结构将有助于回答这些剩余的问题。 对于所有的结构确定项目，我们都需要收集、存储和处理大量数据。 我们的结构生物学方法与功能研究相辅相成，以获得对 以原子分辨率进行糖的运输。我们需要评估异源的功能- 在项目的早期阶段表达的蛋白质。在获得结构后，我们计划 通过在结构中确定的关键位置插入突变来对它们进行交互作用，并筛选小的- 作为潜在的抑制剂的分子。

Abstract Sugars, in particular glucose, are not only a ubiquitous cellular fuel source in virtually all organisms, but also serve as critical metabolic intermediates in which activated glucose molecules are transported to the ER and Golgi and used for glycosylating proteins, lipids and other organic compounds as part of the biosynthetic-secretory pathway. To accomplish these diverse and localized functions, the body utilizes membrane transporters and channels to transfer glucose and its intermediates across the otherwise impermeable membrane lipid bilayer that surrounds all cells and organelles. Secondary active transporters are key mediators in this process. Alternatively, the Voltage Dependent Anion Channel funnels glucose intermediates into the mitochondria where they enter the TCA cycle for the production of ATP. In their essential function for physiology, these proteins are implicated in numerous diseases and are designated targets for pharmaceutical compounds. In the parent R35 entitled, “Deciphering molecular details of cellular sugar transport and their roles in disease” we aim to characterize the structure and function of several families of transporters involved in cellular sugar and metabolite transport. Specifically, we want to study the Sodium Glucose Cotransporter (SGLT), Nucleotide Sugar Transporters (NST) and Sialic Acid Transporter (SiaT) and the Voltage-Dependent Anion Channel (VDAC). Human SGLTs are well known targets for treating Type II diabetes, but the molecular details of inhibition and the functional differences between isoforms are not well understood. This is in large part due to the lack of structural information. NSTs import various activated sugar compounds into the Golgi and ER, whereas SiaT serves to import scavenged sialic acids from its host. Differences between eukaryotic and pathogen NSTs could be exploited for therapeutic purposes. However, this family of transporters is still largely uncharacterized. VDAC is the central mediator of metabolite exchange through the outer mitochondrial membrane. Despite this critical role, key aspects of its functional gating and substrate transport are not well understood. Again, we hope that resolving additional structures of VDAC will help to answer these remaining questions. For all structure determination projects we need to collect, store and process large amounts of data. Our structural biology approach is complemented by functional studies to obtain a complete picture of sugar transport at an atomic resolution. We need to assess the functionality of heterologously- expressed proteins during the early stages of project. After obtaining the structures, we plan to interogate them by inserting mutations at critical sites identified in the structures and screen small- molecules as potential inhibitors.