Calcium and Pancreatic Stimulus-Secretion Coupling

钙和胰腺刺激分泌耦合

• 批准号: 7905584
• 负责人: JOHN A WILLIAMS
• 金额: $ 8.33万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-20 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7905584
• 关键词: Acetylcholine; Acinar Cell; Actins; Acute; Address; Apical; Area; Assimilations; Calcium; Cell membrane; Cholecystokinin; Complex; Coupling; Cyclic AMP; Cytoplasmic Granules; Cytoskeleton; Disease; Docking; Enzymes; Exocytosis; Family; Food; GTP-Binding Proteins; Gastrointestinal Hormones; Goals; Heterotrimeric GTP-Binding Proteins; Hormones; Inflammatory; Lead; Ligands; Mediating; Membrane; Modeling; Molecular; Monomeric GTP-Binding Proteins; Movement; Myosin ATPase; Neurotransmitters; Nutrient; Organ; Pancreas; Pancreatitis; Phosphoric Monoester Hydrolases; Phosphotransferases; Process; Proteins; Proteomics; Public Health; Receptor Activation; Regulation; Research; Role; SNAP receptor; Series; Site; Stimulus; Work; Zymogen Granules; apical membrane; genetic regulatory protein; pancreatic juice; rho; rho GTP-Binding Proteins; trafficking

The overall aim of this research is to understand how regulatory neurotransmitters and gastrointestinal hormones act through changes in intracellular free Ca2+ to bring about digestive enzyme secretion by pancreatic acinar cells. This proposal focuses on the mechanisms involved in the terminal steps in secretion culminating in exocytosis. Using a proteomics discovery strategy, we have identified a number of small GTP binding proteins on the zymogen granule including RabSD, Rab6, Rab11, Rab27B and Rap1. Since Rabs are believed to regulate vesicular trafficking by organizing and regulating effector proteins the focus of this work includes two of these Rab molecules, RabSD and Rab27B as well as Rap1.Two other small G proteins, Rho and Rac which regulate the actin cytoskeleton will also be studied. The overall goal is to determine the role of each of these G proteins in the series of sequential processes by which zymogen granules are brought to the apical membrane, become fusion competent and undergo exocytosis. Specific aims of this proposal include: 1) What is the extent of activation (GTPliganded form) of Rab27B andRap1 on zymogen granules and is it increased by secretagogues such as cholecystokinin (CCK) and acetylcholine? Is Rap1important for secretion as has been shown for RabSD and 27B? Does Rap1 activation mediate the secretory stimulation by cyclic AMP? 2) What are the GEFs or other regulatory protein involved in activating the three granule small G proteins, Rho and Rac? Are they activated by specific heterotrimeric G proteins and/or by intracellular messengers such as Ca2+? Is a cyclic AMP activated GEF (Epac) involved in activating Rap1? 3) What are the downstream effector proteins for RabSD, Rab27B and Rap1? Are linker proteins of the Sip or Slac families involved? Is there a relation of specific small G proteins to myosin Vc? to Noc2? Which small G proteins directly or indirectly regulate SNARE complexes? This work will lead to better molecular understanding of the regulation of digestive enzyme secretion in acinar cells and potential sites for the pathological regulation that occurs in experimental pancreatitis. Relevance to public health: the pancreas is the major organ that secretes digestive breakdown of food and assimilation of nutrients. If these enzymes are not inflammatory disease pancreatitis can result. The present work is directed at understanding of the proteins involved in normal digestive enzyme secretion.

这项研究的总体目标是了解调节神经递质和胃肠 激素通过细胞内游离Ca 2+的变化而起作用， 胰腺腺泡细胞这项建议的重点是在分泌的终端步骤所涉及的机制 最终导致胞吐作用。使用蛋白质组学发现策略，我们已经确定了一些小GTP 酶原颗粒上的结合蛋白包括RabSD、Rab 6、Rab 11、Rab 27 B和Rap 1。自从Rabs 被认为通过组织和调节效应蛋白来调节囊泡运输， 工作包括两个这样的Rab分子，RabSD和Rab 27 B以及Rap 1。 还将研究调节肌动蛋白细胞骨架的蛋白质Rho和Rac。总体目标是 确定这些G蛋白中的每一个在一系列连续过程中的作用， 颗粒被带到顶膜，成为融合感受态并经历胞吐作用。具体 本研究的目的包括：1）Rab 27 B和Rap 1的激活程度（GTP配体形式）是什么 在酶原颗粒上，它是由促分泌素如胆囊收缩素（CCK）和 乙酰胆碱？Rap 1对分泌是否像RabSD和27 B一样重要？Rap 1是否 激活介导的分泌刺激环磷酸腺苷？2)全球环境基金或其他监管机构 蛋白参与激活三个颗粒小G蛋白，Rho和Rac？它们是由 特异性异源三聚体G蛋白和/或细胞内信使，如Ca 2+？是一种环磷酸腺苷 激活GEF（Epac）参与激活Rap 1？3)RabSD的下游效应蛋白是什么， Rab 27 B和Rap 1？是否涉及Sip或Slac家族的连接蛋白？是否存在特定的 小G蛋白转化为肌球蛋白Vc？NOC2？哪些小G蛋白直接或间接调节SNARE 情结？这项工作将有助于从分子水平更好地理解消化酶的调节 腺泡细胞分泌和潜在的网站的病理调节发生在实验 胰腺炎 与公共卫生的相关性：胰腺是分泌消化系统的主要器官。 分解食物和吸收营养。如果这些酶不是 可能导致炎症性疾病胰腺炎。本工作针对 了解参与正常消化酶分泌的蛋白质。