cAMP-mediated signaling regulates a myriad of important biological processes under physiological conditions and disease states, including diabetes, heart failure and cancer. In eukaryotic cells, the effects of cAMP are mediated by two ubiquitously expressed intracellular cAMP receptors, the classic protein kinase A/cAMP-dependent protein kinase (PKA/cAPK) and the recently discovered exchange protein directly activated by cAMP/cAMP-regulated guanine nucleotide exchange factor (Epac/cAMP-GEF). The existence of two ubiquitously expressed cAMP effectors provides a mechanism for a more precise and integrated control of the cAMP signaling pathways in a spatial and temporal manner. However, little is known about the mechanism of Epac activation. The objective of this proposal is to fill the gap in our current knowledge by mapping the conformational changes associated with Epac activation. Specifically, we have planned experiments with the following Specific Aims: 1) To determine the specific residues important for Epac activation by site-directed mutagenesis;2) to delineate the conformational changes associated with cAMP binding and Epac activation and to determine the protein interface between Epac and its downstream effector, Rap1, using enhanced deuterium exchange-mass spectrometry (DXMS) and small-angle X-ray scattering;and 3) to solve the crystal structure of Epac2-cAMP using X-ray crystallography. The long-term goals of our research are to understand the physiological functions and mechanisms of Epac regulation. Accomplishing the proposed research in this application will significantly move the field forward towards these goals. Furthermore, the medical and pharmacological implications of this research program are also far-reaching. A better understanding of cAMP mediated signal transduction could potentially lead to the identification of novel mechanism-based therapeutic strategies specifically targeting the cAMP-signaling components.
Cyclic AMP-mediated signaling regulates a myriad of important biological processes under both physiological conditions and disease states, including diabetes, heart failure and cancer. Components of the cAMP-signaling cascade have been implicated in abnormal cell growth and drug actions and successfully targeted for diagnosis and chemotherapy of cancer and other diseases. A better understanding of cAMP mediated signal transduction could potentially lead to the identification of novel drug targets and the development of new or improved therapeutic agents.
|Zhu, Yingmin; Mei, Fang; Luo, Pei et al. (2017) A cell-based, quantitative and isoform-specific assay for exchange proteins directly activated by cAMP. Sci Rep 7:6200|
|Wang, Pingyuan; Liu, Zhiqing; Chen, Haiying et al. (2017) Exchange proteins directly activated by cAMP (EPACs): Emerging therapeutic targets. Bioorg Med Chem Lett 27:1633-1639|
|Liu, Zhiqing; Zhu, Yingmin; Chen, Haiying et al. (2017) Structure-activity relationships of 2-substituted phenyl-N-phenyl-2-oxoacetohydrazonoyl cyanides as novel antagonists of exchange proteins directly activated by cAMP (EPACs). Bioorg Med Chem Lett 27:5163-5166|
|Almahariq, Muayad; Mei, Fang C; Cheng, Xiaodong (2016) The pleiotropic role of exchange protein directly activated by cAMP 1 (EPAC1) in cancer: implications for therapeutic intervention. Acta Biochim Biophys Sin (Shanghai) 48:75-81|
|Wild, Christopher T; Zhu, Yingmin; Na, Ye et al. (2016) Functionalized N,N-Diphenylamines as Potent and Selective EPAC2 Inhibitors. ACS Med Chem Lett 7:460-4|
|Singhmar, Pooja; Huo, XiaoJiao; Eijkelkamp, Niels et al. (2016) Critical role for Epac1 in inflammatory pain controlled by GRK2-mediated phosphorylation of Epac1. Proc Natl Acad Sci U S A 113:3036-41|
|Hu, Yaohua; Robichaux 3rd, William G; Mei, Fang C et al. (2016) Role of Exchange Protein Directly Activated by Cyclic AMP Isoform 1 in Energy Homeostasis: Regulation of Leptin Expression and Secretion in White Adipose Tissue. Mol Cell Biol 36:2440-50|
|Wang, Hui; Robichaux, William G; Wang, Ziqing et al. (2016) Inhibition of Epac1 suppresses mitochondrial fission and reduces neointima formation induced by vascular injury. Sci Rep 6:36552|
|Zhu, Yingmin; Chen, Haijun; Boulton, Stephen et al. (2015) Biochemical and pharmacological characterizations of ESI-09 based EPAC inhibitors: defining the ESI-09 ""therapeutic window"". Sci Rep 5:9344|
|Banerjee, Upasana; Cheng, Xiaodong (2015) Exchange protein directly activated by cAMP encoded by the mammalian rapgef3 gene: Structure, function and therapeutics. Gene 570:157-67|
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