Exchange Protein directly Activated by cAMP (EPAC): Structure, Function and Therapeutics

项目摘要 这是响应RFA-GM-17-002“最大化研究者研究奖（R35）”的R35申请。 本实验室致力于研究多效性第二信使环腺苷酸（cAMP）系统。营是一个 主要的压力信号，调节无数重要的生物过程下的生理和 病理状况，包括癌症、慢性疼痛、糖尿病、心力衰竭和感染。因此不 令人惊讶的是，cAMP信号级联是目前药物最具靶向的途径之一。在 在多细胞真核生物中，cAMP的作用主要通过两种普遍表达的 细胞内cAMP受体、经典蛋白激酶A/cAMP依赖性蛋白激酶（PKA/cAPK）和 最近发现的由cAMP/cAMP调节的鸟嘌呤直接激活的交换蛋白 核苷酸交换因子（EPAC/cAMP-GEF）。虽然越来越多的证据表明EPAC蛋白是 重要的压力反应开关在各种人类疾病的发展，主要差距，我们的基本 对EPAC结构和功能的理解仍然存在。为了弥合这些差距，我们将采用结构， 药理学和遗传学的方法来询问的作用机制和生物学功能， 这一重要的信号分子家族，导致评估EPAC蛋白作为潜在的 各种疾病模型中的治疗靶点。这项研究是基于17年多的 EPAC介导的信号传导的广泛基础研究，并直接建立在最近的几个 我们实验室的发展，其中包括EPAC敲除小鼠的特征和发现 一流的EPAC特异性抑制剂互补结构方法的组合，新颖 遗传动物模型和药理学探针将使我们能够揭示更渴望的机制见解 以及EPAC蛋白的体内功能。这项研究计划还将有助于推动新的 用于破译EPAC介导的细胞信号传导和疾病机制的药理学工具， 新的，基于机制的治疗策略，特别是针对cAMP/EPAC信号的方式。

PROJECT SUMMARY This is an R35 application in response to RFA-GM-17-002 “Maximizing Investigators’ Research Award (R35)". Our laboratory focuses on studying the pleiotropic second messenger cyclic AMP (cAMP) system. cAMP is a major stress signal that regulates a myriad of important biological processes under both physiological and pathological conditions, including cancer, chronic pain, diabetes, heart failure, and infections. Hence, not surprisingly, the cAMP signaling cascade is one of the most targeted pathways by current pharmaceuticals. In multi-cellular eukaryotic organisms, the effects of cAMP are mainly transduced by two ubiquitously-expressed intracellular cAMP receptors, the classic protein kinase A/cAMP-dependent protein kinase (PKA/cAPK) and the more recently discovered exchange proteins directly activated by cAMP/cAMP-regulated guanine nucleotide exchange factor (EPAC/cAMP-GEF). While accumulating evidence implicates EPAC proteins as important stress response switches in the development of various human diseases, major gaps in our basic understanding of EPAC structures and functions persist. To bridge these gaps, we will apply structural, pharmacological and genetic approaches to interrogate the mechanisms of action and biological functions of this important family of signaling molecules, leading to the assessment of EPAC proteins as potential therapeutic targets in various disease models. The proposed research is based on more than seventeen years of extensive fundamental studies of EPAC-mediated signaling and directly builds on a several recent developments in our laboratory, which include the characterization of EPAC knockout mice and the discovery of first-in-class EPAC specific inhibitors. The combination of complementary structural approaches, novel genetic animal models and pharmacological probes will enable us to reveal much desired mechanistic insight and in vivo functions of EPAC proteins. This research plan will also aid in the advancement of new pharmacological tools for deciphering EPAC-mediated cell signaling and disease mechanisms, which can pave the way for novel, mechanism-based therapeutic strategies specifically targeting cAMP/EPAC signaling.