Molecular functions of human zinc transporter-8 in pancreatic beta cells

人锌转运蛋白 8 在胰腺 β 细胞中的分子功能

• 批准号: 10321946
• 负责人: Dax Fu
• 金额: $ 49.76万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10321946
• 关键词: Address; Autoantigens; Beta Cell; Binding; Binding Proteins; Biochemistry; Biological; Biological Models; Biology; Biomimetics; Carrier Proteins; Cell physiology; Cell surface; Cells; Cellular Stress; Cellular biology; Client; Complex; Coupling; Crystallization; Cytoplasm; Data; Disease; Endocrine; Endoplasmic Reticulum; Ensure; Equilibrium; Exocytosis; Glucose; Goals; Homeostasis; Homologous Gene; Housekeeping; Human; Human body; Immunoassay; Individual; Inflammation; Inflammatory; Insulin; Islets of Langerhans; Knowledge; Lipids; Location; Mammalian Cell; Mediating; Messenger RNA; Metabolic; Metals; Minor; Modeling; Molecular; Monoclonal Antibodies; Non-Insulin-Dependent Diabetes Mellitus; Pathogenesis; Play; Population; Process; Production; Protein Conformation; Protein Dynamics; Proteins; Proteome; Proteomics; Publishing; Quality Control; Regulation; Research; Role; Secretory Vesicles; Signal Transduction; Specificity; Stimulus; Stress; Structure of beta Cell of islet; Surface; Testing; Time; Tube; Ubiquitination; Vacuum; Zinc; alpha Tubulin; atomic interactions; base; cross reactivity; cytokine; endoplasmic reticulum stress; genetic regulatory protein; insulin secretion; islet; loss of function mutation; response; restoration; spatiotemporal; zinc-binding protein

Abstract Zinc is a ubiquitous biological metal found in about 10% of the eukaryotic proteome. The spatiotemporal zinc dynamics provides crucial cellular signaling opportunities, but also challenges intracellular zinc homeostasis with broad disease implications. Zinc transporters play a central role in regulating cellular zinc balance and subcellular zinc distributions. Current biochemistry of zinc transporters is largely based on purified proteins in test-tubes. However, the molecular functions of zinc transporters in mammalian cells are cell context dependent, vary with subcellular locations and regulated by pathophysiologic stimuli. At present, we have no knowledge of in-cell functions of endogenous zinc transporters at the molecular level. To fill in this knowledge vacuum, we will use an islet-specific zinc transporter ZnT8 and its host cells, the insulin-producing pancreatic β-cells as a mammalian model system to address two questions of the greatest importance to zinc biology: (i) how ZnT8-mediated zinc transport is compartmentalized at the correct subcellular locations to perform intended tasks, (ii) how the biosynthetic burden of ZnT8 is managed by the protein quality control network that ensures clearance of terminally damaged ZnT8 under cell stress. The second question is not directly related to zinc transport, but has a profound impact on β-cell biology with implications in pathogenesis of type-2 diabetes. Our prior studies have uncovered functional coupling of ZnT8 and insulin in two critical cellular processes, glucose-stimulated insulin secretion and inflammation-induced unfolded protein response in the endoplasmic reticulum. The proposed research will characterize subcellular locations and protein levels of endogenous ZnT8 in response to metabolic and inflammatory stress (Aim-1), identify regulators of ZnT8 subcellular functions, and elucidate their mechanism of actions (Aim-2). The proposed research will reveal unprecedented molecular details of ZnT8 subcellular functions in molecular and cellular processes that impact cell biology of host cells, leading to a new paradigm of in-cell molecular functions of zinc transporters in mammalian cells.

摘要 锌是一种普遍存在的生物金属，存在于约10%的真核蛋白质组中。时空锌 动力学提供了关键的细胞信号转导机会，但也挑战了细胞内锌的动态平衡 广泛的疾病含义。锌转运蛋白在调节细胞内锌平衡和亚细胞内起核心作用 锌的分布。目前锌转运蛋白的生物化学主要基于试管中纯化的蛋白质。 然而，哺乳动物细胞中锌转运蛋白的分子功能依赖于细胞环境，不同 亚细胞定位，并受病理生理刺激调节。目前，我们还不了解In-cell 内源性锌转运蛋白在分子水平上的功能。为了填补这一知识真空，我们将使用 胰岛特异性锌转运蛋白ZnT8及其宿主细胞--哺乳动物分泌胰岛素的胰腺β细胞 解决锌生物学最重要的两个问题的模型系统：(I)锌是如何介导锌的 运输在正确的亚蜂窝位置被划分以执行预期的任务，(Ii)如何 锌的生物合成负荷由蛋白质质量控制网络管理，确保清除 在细胞胁迫下，最终破坏了ZnT8。第二个问题与锌的运输没有直接关系，但已经 对β细胞生物学的深刻影响及其在2型糖尿病发病机制中的意义。我们之前的研究已经 在葡萄糖刺激的胰岛素这两个关键的细胞过程中发现了ZnT8和胰岛素的功能偶联 内质网分泌和炎症诱导的未折叠蛋白反应。建议数 研究将表征内源性ZnT8的亚细胞位置和蛋白质水平对代谢的响应 和炎性应激(AIM-1)，鉴定锌锌亚细胞功能的调节因子，并阐明其机制 行动计划(AIM-2)。这项拟议的研究将揭示史无前例的znt8亚细胞分子细节。 在分子和细胞过程中影响宿主细胞生物学的功能，导致了一种新的 哺乳动物细胞中锌转运蛋白的细胞内分子功能。