Structure and Function of SWEET Sugar Transporters

SWEET糖转运蛋白的结构和功能

• 批准号: 9333389
• 负责人: Liang Feng
• 金额: $ 31.21万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9333389
• 关键词: Active Biological Transport; Amino Acids; Architecture; Biological Assay; Biological Models; Blood Glucose; Carbon; Carrier Proteins; Complement; Crystallization; Cystinosis; Data; Diabetes Mellitus; Diffusion; Dimerization; Disaccharides; Drug Targeting; Electron Spin Resonance Spectroscopy; Energy-Generating Resources; Evolution; Future; Goals; Growth; Homeostasis; Homologous Gene; In Vitro; KDEL receptor; Knowledge; Learning; Light; Link; Lysosomal Storage Diseases; Lysosomes; Maintenance; Malignant Neoplasms; Mediating; Membrane; Membrane Proteins; Membrane Transport Proteins; Metabolism; Mitochondria; Modeling; Molecular; Molecular Conformation; Mono-S; Mutagenesis; Non-Insulin-Dependent Diabetes Mellitus; Organism; Physiological; Physiological Processes; Property; Protein Engineering; Protein Isoforms; Proteins; Research; Resolution; Sorting - Cell Movement; Spielmeyer-Vogt Disease; Structure; Substrate Specificity; Transmembrane Transport; Transport Process; Work; X-Ray Crystallography; Yeasts; biophysical techniques; cancer type; crosslink; dimer; driving force; drug development; improved; member; milk production; mutation screening; novel; novel therapeutics; prototype; public health relevance; pyruvate carrier; receptor; sugar; targeted treatment; therapeutic target; triple helix; uptake

 DESCRIPTION (provided by applicant): Sugar is a key source of energy for multicellular organisms, and its efflux across the membrane is critical to many physiological processes, including blood glucose maintenance and milk production. SWEET transporters (SWEETs) are novel membrane proteins that mediate sugar export. SWEETs are also prototypes of the large MtN3 membrane protein clan, which includes notable members such as mitochondrial pyruvate carrier, PQ-loop transporters and the KDEL receptor. Eukaryotic SWEETs, together with their "half transporter" bacterial homolog, SemiSWEET, are a unique model system to study the widely observed duplication-fusion in membrane protein evolution. Despite the importance of SWEETs in sugar utilization and MtN3 proteins in mitochondrial function, lysosomal amino acid homeostasis, and ER protein retention, we do not understand SWEET and MtN3 mechanisms at the molecular level. To overcome a major barrier to progress-the lack of a structural framework to guide our mechanistic understanding of transport-we have solved high-resolution structures of two SemiSWEET proteins, in two distinct conformational states: outward open and occluded. We will leverage this structural data to gain a detailed understanding of the structure and function of SWEETs and, more broadly, of MtN3s. Specific Aim 1: Elucidate the structural basis of sugar transport by SemiSWEET using X-ray crystallography and biophysical methods. These studies will help us understand the physical basis of sugar transport by SemiSWEETs. Specific Aim 2: Determine the first crystal structure of a eukaryotic SWEET. This structural information will provide a blueprint for the transport process and help elucidate the evolution of membrane transport proteins with internal symmetry. Specific Aim 3: Dissect the transport mechanism of SWEETs and MtN3s through functional studies. Fundamental aspects of SWEET-mediated transport will be elucidated and then extended to members of the MtN3 clan. OVERALL IMPACT: The proposed research will reveal the structural basis of sugar transport by SWEETs, elucidate their transport mechanism, and accelerate exploration of MtN3s as therapeutic targets to treat diabetes, cancer and lysosomal storage diseases.

 描述（由适用提供）：糖是多细胞生物的关键能源，其在整个膜上的外排对于许多物理过程，包括血糖维持和牛奶的产生至关重要。甜味转运蛋白（甜点）是介导糖出口的新型膜蛋白。糖果也是大型MTN3膜蛋白氏族的原型，其中包括著名成员，例如线粒体丙酮酸载体，PQ-LOOP转运蛋白和KDEL接收器。真核糖果及其“半转运蛋白”细菌同源物半甜，是一个独特的模型系统，可研究膜蛋白演化中广泛观察到的重复融合。尽管糖在糖的利用和MTN3蛋白中的重要性在线粒体功能，溶酶体氨基酸稳态和ER蛋白保留方面的重要性，但我们不了解分子水平的甜和MTN3机制。为了克服进步的主要障碍 - 缺乏指导我们对运输的机械理解的结构框架，我们解决了两个半蛋白质的高分辨率结构，在两个不同的构象状态下：向外开放和遮挡。我们将利用这些结构数据来详细了解糖果的结构和功能，更广泛地了解MTN3。特定目标1：使用X射线晶体学和生物物理方法通过半效率阐明糖传输的结构基础。这些研究将有助于我们了解半甜糖运输的物理基础。特定目标2：确定真核甜味的第一个晶体结构。这些结构信息将为运输过程提供蓝图，并有助于用内部对称性阐明膜转运蛋白的演变。特定目的3：通过功能研究剖析糖果和MTN3的运输机制。甜味介导的运输的基本方面将被阐明，然后扩展到MTN3家族的成员。总体影响：拟议的研究将揭示糖果糖运输的结构基础，阐明其运输机制，并加速对MTN3的探索，作为治疗糖尿病，癌症和溶酶体储存疾病的治疗靶标。