Structural analyses of a constitutively active mutant of exchange protein directly activated by cAMP

• Published in: PloS one Vol. 7; no. 11; p. e49932
• Main Authors: White, Mark A, Li, Sheng, Tsalkova, Tamara, Mei, Fang C, Liu, Tong, Woods, Jr, Virgil L, Cheng, Xiaodong
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26.11.2012; Public Library of Science (PLoS)
• Subjects: Activation; Allosteric properties; Analysis; Biology; Biophysics; Catalytic Domain; Cell adhesion & migration; Cellular signal transduction; Crystal structure; Crystallography; Crystallography, X-Ray; Cyclic adenosine monophosphate; Cyclic AMP; Cyclic AMP - chemistry; Cyclic AMP - metabolism; Deuterium; Deuterium - chemistry; Dynamic structural analysis; Exchanging; Glycerol; Glycine; Guanine Nucleotide Exchange Factors - chemistry; Guanine Nucleotide Exchange Factors - genetics; Humans; Hydrogen; Hydrogen - chemistry; Kinases; Mass spectrometry; Mass spectroscopy; Models, Molecular; Mutagenesis; Mutation; Pharmacology; Protein Binding; Protein Conformation; Protein Interaction Domains and Motifs; Proteins; Regulators; Scientific imaging; Site-directed mutagenesis; Toxicology; Transduction; X-ray crystallography; La Jolla California; California; United States > US; Texas
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0049932

Exchange proteins directly activated by cAMP (EPACs) are important allosteric regulators of cAMP-mediated signal transduction pathways. To understand the molecular mechanism of EPAC activation, we have combined site-directed mutagenesis, X-ray crystallography, and peptide amide hydrogen/deuterium exchange mass spectrometry (DXMS) to probe the structural and conformational dynamics of EPAC2-F435G, a constitutively active EPAC2 mutant. Our study demonstrates that conformational dynamics plays a critical role in cAMP-induced EPAC activation. A glycine mutation at 435 position shifts the equilibrium of conformational dynamics towards the extended active conformation.