RECEPTORS FOR CCK AND OTHER GI-HORMONES

描述：(改编自申请人摘要)：这份修改后的申请 试图了解胰腺腺泡细胞和 蛙皮素(Bn)和胆囊素(CCKA)或胃泌素(CCKb)受体。 胰腺腺泡细胞对食物的消化至关重要，并参与了 病理状态包括胰腺炎和胰腺癌。BN和CCK 受体调节腺泡细胞功能，自身受腺泡细胞调节 细胞机制。Bn和Bn的分子机理和结构特征 影响腺泡细胞功能的CCK受体尚未确定。这个 这项提议的第一个具体目标是确定 Bn、CCKA和CCKB与胰腺腺泡生物学偶联的差异 功能和细胞信号。Bn、CCKA和CCKB受体的功能 来自人类和啮齿动物的细胞将在腺泡细胞中进行比较。为此， 基因转移技术，凋亡腺病毒载体或转基因 动物，将被雇佣。腺泡内表达这些受体的作用 受体上的细胞对包括分泌物在内的生物反应进行耦合， 蛋白质合成和炎性介质的产生，以及 我们将研究与这些响应中的每一个相关的信号机制。 这些研究将允许不同受体之间的第一次直接比较 腺泡细胞环境中不同物种的亚型和受体。 突变受体将被用来确定受体的结构基础 耦合。第二个具体目标是确定细胞机制和 胰腺受体转运中的受体结构特征 腺泡细胞。目前对CCKB或Bn受体贩运一无所知 胰腺腺泡细胞。CCKA受体被固定在腺泡细胞上 通过激动剂职业浮出水面，但不内化。这种图案是独一无二的 到腺泡细胞，因为这些受体在成纤维细胞模型中内化。 人类和啮齿动物CkB和Bn受体的运输特征将 在胰腺腺泡细胞中进行生化和成像检查 技巧。然后，特定的结构域和位点在受体中的作用 将对人口贩运进行审查。此外，重要的分子子集在 将探索受体运输，包括G蛋白偶联受体 人和小鼠胰腺腺泡细胞中的激活酶(GRK)和阻滞素。 过表达相关亚型对受体转运的影响 这些分子和它们的主要负向对应物，或反义 将对构造进行检查。第三个特定目标将决定细胞 受体参与的机制和受体结构特征 胰腺腺泡细胞脱敏。人们对此知之甚少 脱敏特性或参与的分子机制 Bn或CCK受体的脱敏。阿司匹林脱敏特性 不同的受体将在胰腺腺泡细胞生物学上定义 响应和细胞信号。突变受体将被用来确定 受体脱敏的结构基础。此外， 操纵GRK和阻滞剂的脱敏作用将在腺泡上进行检查 细胞生物学反应和相关的细胞内信号。把这些放在一起 研究将为调控机制提供重要的见解。 胰腺腺泡细胞功能。

DESCRIPTION: (Adapted from the Applicant's Abstract): This revised application seeks to understand the interactions between pancreatic acinar cells and receptors for bombesin (Bn) and cholecystokinin (CCKA) or gastrin (CCKB). Pancreatic acinar cells are critical for digestion of food and are involved in pathological states including pancreatitis and pancreatic cancer. Bn and CCK receptors regulate acinar cell function and are themselves regulated by acinar cell mechanisms. The molecular mechanisms and the structural features of Bn and CCK receptors that influence acinar cell function have not been identified. The first specific aim of this proposal is to determine the molecular basis for differences in Bn, CCKA, and CCKB coupling to pancreatic acinar biological functions and cell signaling. The functioning of Bn, CCKA, and CCKB receptors from humans and rodents will be compared in acinar cells. For this purpose, gene transfer techniques, wither adenoviral-based vectors or transgenic animals, will be employed. The effects of expressing those receptors in acinar cells on receptor coupling to biological responses, including secretion, protein synthesis, and the generation of inflammatory mediators, and the signaling mechanisms associated with each of those responses will be examined. These studies will allow the first direct comparison between different receptor subtypes and receptors from different species in an acinar cell environment. Mutant receptors will be utilized to determine the structural basis of receptor coupling. The second specific aim is to determine the cellular mechanisms and receptor structural features involved in receptor trafficking in pancreatic acinar cells. Nothing is known concerning CCKB or Bn receptor trafficking in pancreatic acinar cells. CCKA receptors are immobilized on the acinar cell surface by agonist occupation but are not internalized. This pattern is unique to the acinar cell as these receptors are internalized in fibroblast models. The trafficking characteristics of human and rodent CKB and Bn receptors will be examined in pancreatic acinar cells employing biochemical and imaging techniques. Then, the role of specific domains and sites in receptor trafficking will be examined. Also, the subset of molecules important in receptor trafficking will be explored, including G protein-coupled receptor kinases (GRKs) and arrestins, in pancreatic acinar cells from humans and mice. The effects on receptor trafficking of over-expressing the relevant isoforms of these molecules and their dominant negative counterparts, or anti-sense constructs will be examined. The third specific aim will determine the cellular mechanisms and receptor structural features involved in receptor desensitization in pancreatic acinar cells. Little is known about the desensitization characteristics or molecular mechanisms involved in the desensitization of Bn or CCK receptors. The desensitization characteristics of the different receptors will be defined on pancreatic acinar cell biological responses and cell signals. Mutant receptors will be employed to determine the structural basis for receptor desensitization. Also, the effects of manipulating GRKs and arrestins on desensitization will be examined on acinar cell biological responses and associated intracellular signals. Together these studies will provide important insights into the mechanisms regulating pancreatic acinar cell function.