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

PLoS One. 2012;7(11):e49932. doi: 10.1371/journal.pone.0049932. Epub 2012 Nov 26.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Catalytic Domain
  • Crystallography, X-Ray
  • Cyclic AMP / chemistry
  • Cyclic AMP / metabolism
  • Deuterium / chemistry
  • Guanine Nucleotide Exchange Factors / chemistry*
  • Guanine Nucleotide Exchange Factors / genetics
  • Humans
  • Hydrogen / chemistry
  • Models, Molecular
  • Mutation
  • Protein Binding
  • Protein Conformation
  • Protein Interaction Domains and Motifs

Substances

  • Guanine Nucleotide Exchange Factors
  • RAPGEF3 protein, human
  • Hydrogen
  • Deuterium
  • Cyclic AMP