Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCyclic adenosine monophosphate (cAMP) is a universal second messenger that, in eukaryotes, was believed to act only on cAMP-dependent protein kinase A (PKA) and cyclic nucleotide-regulated ion channels. Recently, guanine nucleotide exchange factors specific for the small GTP-binding proteins Rap1 and Rap2 (Epacs) were described, which are also activated directly by cAMP. Here, we have determined the three-dimensional structure of the regulatory domain of Epac2, which consists of two cyclic nucleotide monophosphate (cNMP)-binding domains and one DEP (Dishevelled, Egl, Pleckstrin) domain. This is the first structure of a cNMP-binding domain in the absence of ligand, and comparison with previous structures, sequence alignment and biochemical experiments allow us to delineate a mechanism for cyclic nucleotide-mediated conformational change and activation that is most likely conserved for all cNMP-regulated proteins. We identify a hinge region that couples cAMP binding to a conformational change of the C-terminal regions. Mutations in the hinge of Epac can uncouple cAMP binding from its exchange activity. Structure and regulation of the cAMP-binding domains of Epac2.,Rehmann H, Prakash B, Wolf E, Rueppel A, de Rooij J, Bos JL, Wittinghofer A Nat Struct Biol. 2003 Jan;10(1):26-32. PMID:12469113[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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