Bos Johannes L
Department of Physiological Chemistry and Centre for Biomedical Genetics, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
Trends Biochem Sci. 2006 Dec;31(12):680-6. doi: 10.1016/j.tibs.2006.10.002. Epub 2006 Nov 2.
Epac1 and Epac2 are cAMP-dependent guanine-nucleotide-exchange factors for the small GTPases Rap1 and Rap2, and are known to be important mediators of cAMP signaling. The recent determination of the crystal structure of Epac2 has indicated a mechanism for the activation of the multi-domain Epac proteins. In addition, these proteins have been implicated in various cellular processes such as integrin-mediated cell adhesion and cell-cell junction formation, the control of insulin secretion and neurotransmitter release. In most of these processes, cAMP signaling through protein kinase A (PKA) is also involved, stressing the interconnectivity between Epac- and PKA-mediated signaling.
Epac1和Epac2是小GTP酶Rap1和Rap2的环磷酸腺苷（cAMP）依赖性鸟嘌呤核苷酸交换因子，已知是cAMP信号传导的重要介质。最近对Epac2晶体结构的测定揭示了多结构域Epac蛋白的激活机制。此外，这些蛋白还参与了多种细胞过程，如整合素介导的细胞黏附和细胞间连接形成、胰岛素分泌和神经递质释放的调控。在大多数这些过程中，也涉及通过蛋白激酶A（PKA）的cAMP信号传导，这突出了Epac和PKA介导的信号传导之间的相互联系。
