Calcium and Pancreatic Stimulus-Secretion Coupling

这项研究的总体目标是了解调节性神经递质和胃肠道 激素通过改变细胞内游离钙离子，通过以下途径促进消化酶分泌 胰腺腺泡细胞。这项建议侧重于分泌的末端步骤所涉及的机制。 最终导致胞吐。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、Rab6、Rab11、Rab27B和Rap1。自从拉布斯 被认为通过组织和调节效应蛋白来调节囊泡的运输 工作包括两个这样的Rab分子，RabSD和Rab27B以及Rap1。另外两个小G 调节肌动蛋白细胞骨架的蛋白质、Rho和Rac也将被研究。总体目标是 确定这些G蛋白中的每一个在酶原通过的一系列顺序过程中的作用 颗粒被带到顶膜，具有融合能力并经历胞吐作用。特定的 这项建议的目的包括：1)Rab27B和RAP1的激活程度(GT Pliganed Form)是多少 对酶原颗粒的影响以及促分泌剂如CCK和 乙酰胆碱？Rap1对分泌是否像对RabSD和27B一样重要？Rap1有没有 激活介导环状AMP的分泌刺激？2)GEF或其他调节因子是什么 参与激活Rho和Rac三种颗粒小G蛋白的蛋白质？它们是否由 特异的异源三聚体G蛋白和/或细胞内信使，如钙离子？是一个循环AMP 激活的环境蛋白(EPAC)参与激活Rap1？3)RabSD的下游效应蛋白是什么， Rab27B和Rap1？是否与sip或slac家族的连接蛋白有关？是否存在特定的关系 小G蛋白对肌球蛋白VC？转到2号？哪些小G蛋白直接或间接调节SNARE 情结？这项工作将带来对消化酶调节的更好的分子理解。 实验性腺泡细胞分泌及其可能的病理调控部位 胰腺炎。 与公众健康相关：胰腺是分泌消化的主要器官 食物的分解和营养物质的吸收。如果这些酶不是 炎症性疾病可导致胰腺炎。目前的工作是针对 了解正常消化酶分泌所涉及的蛋白质。

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.