Molecular signal transduction of cAMP compartments

大量G蛋白偶联受体（GPCR）利用cAMP作为其第二信使， 诱导细胞功能改变。事实上，在同一细胞中，几种不同的GPCR都可以增加cAMP， 这就引出了一个问题，即细胞如何以不同的方式解释来自这些受体的信号。的 cAMP区室化的概念，其中第二信使不是均匀产生的 在整个细胞中，很容易被接受，但了解甚少。我们发现， 腺苷酸环化酶（AC）在血浆中的分布并不均匀 膜的此外，由于共定位，GPCR可以优先与某些AC同种型偶联 在脂筏中。虽然我们在了解特定受体如何与 对于某些AC，在确定细胞内cAMP的区室方面几乎没有进展， 关于不同的cAMP库可以改变什么样的细胞反应，我们知道的甚至更少。一 问题是该领域中使用的普通细胞模型缺乏高度区室化的cAMP库。 我们发现培养的人气道平滑肌细胞表达可识别的cAMP 隔间此外，我们可以根据AC的亚型定义这些区室， 快车 我们已经观察到，由AC 2而不是AC 6或其他AC产生的cAMP的信号传导导致了AC 2的表达。 通过HASM表达IL-6。此外，由AC 6而不是由AC 2产生的cAMP增加， 生长抑素的表达，并刺激细胞形状的变化，称为树枝状。因此，AC 2-和 AC 6特异性应答可用于定义HASM中的cAMP信号传导区室。目标 本项目的目的是通过使用 特异性AKAP和PDE的过表达和敲低。新型AC突变体将用于 操纵AC定位和功能，以确定这些池如何组装。这个项目 提出了新的，多学科的方法来定义负责建立的组件 并维持cAMP信号传导区室。结果将具有广泛的适用性，因为 cAMP信号传导的基本性质，但由于使用了分化良好的细胞模型，我们的 研究结果也将与哮喘和COPD治疗直接相关。 GM 107094奥斯特罗姆，雷诺斯S 2.

A large number of G protein coupled receptors (GPCR) utilize cAMP as their second messenger to induce alterations in cell function. In fact, in the same cell several different GPCR can increase cAMP, leading to the question of how the cell interprets the signals from these receptors differently. The concept of cAMP compartmentation, where the second messenger is not generated uniformly throughout the cell, is readily accepted yet poorly understood. We have found that the enzymes that synthesize cAMP, adenylyl cyclases (AC's), are not uniformly distributed through the plasma membrane. Furthermore, GPCR can preferentially couple to certain AC isoforms due to colocalization in lipid rafts. While we have made progress in understanding how specific receptors can couple to certain AC's, little progress has been made in defining the compartments of cAMP inside cells and even less is known about what cellular responses can be modified by different pools of cAMP. One problem has been that common cell models used in the field lack highly compartmentized cAMP pools. We have found that cultured human airway smooth muscle (HASM) cells express identifiable cAMP compartments. Furthermore, we can define these compartments based on the isoforms of AC they express. We have observed that signaling by cAMP generated by AC2, but not AC6 or other AC's, leads to the expression of IL-6 by HASM. Moreover, cAMP generated by AC6, but not by AC2, increases expression of somatostatin and stimulates a cell shape change called arborization. Thus, AC2- and AC6-specific responses can be used to define the cAMP signaling compartments in HASM. The goal of this project is to characterize the other components of these two cAMP compartments by using overexpression and knockdown of specific AKAP's and PDE's. Novel AC mutants will be used to manipulate AC localization and function to determine how these pools are assembled. This project proposes novel, multidisciplinary approaches to define the components responsible for establishing and maintaining cAMP signaling compartments. Results will have broad applicability due to the fundamental nature of cAMP signaling, but because a well-differentiated cell model is used, our findings will also have direct relevance to asthma and COPD therapy. GM107094 Ostrom, Rennolds S 2.