Analysis of an activator:coactivator complex reveals an essential role for secondary structure in transcriptional activation

Mol Cell. 1998 Sep;2(3):353-9. doi: 10.1016/s1097-2765(00)80279-8.


Ser-133 phosphorylation of CREB within the kinase-inducible domain (KID) promotes target gene activation via complex formation with the KIX domain of the coactivator CBP. Concurrent phosphorylation of CREB at Ser-142 inhibits transcriptional induction via an unknown mechanism. Unstructured in the free state, KID folds into a helical structure upon binding to KIX. Using site-directed mutagenesis based on the NMR structure of the KID:KIX complex, we have examined the mechanisms by which Ser-133 and Ser-142 phosphorylation regulate CREB activity. Our results indicate that phospho-Ser-133 stablizes whereas phospho-Ser-142 disrupts secondary structure-mediated interactions between CREB and CBP. Thus, differential phosphorylation of CREB may form the basis by which upstream signals regulate the specificity of target gene activation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Casein Kinase II
  • Cell Line
  • Cyclic AMP Response Element-Binding Protein / chemistry*
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Humans
  • Kinetics
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptide Library
  • Phosphorylation
  • Phosphoserine*
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Structure, Secondary*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Serine
  • Substrate Specificity
  • Transcriptional Activation*
  • Transfection


  • Cyclic AMP Response Element-Binding Protein
  • Peptide Library
  • Recombinant Proteins
  • Phosphoserine
  • Serine
  • Casein Kinase II
  • Protein Serine-Threonine Kinases
  • Cyclic AMP-Dependent Protein Kinases