Phosphorylation of CREB by CaM-kinase IV activated by CaM-kinase IV kinase

Biochem Biophys Res Commun. 1995 Feb 27;207(3):1038-43. doi: 10.1006/bbrc.1995.1289.

Abstract

Previous reports have shown that CaM-kinase IV can phosphorylate the transcription factor CREB in vitro on Ser133. Furthermore, transfected CaM-kinase IV can activate CREB-dependent transcription, but at a lower efficiency than the cAMP-kinase. In this paper we examine the kinetics and site-specificity of CREB phosphorylation in vitro by CaM-kinase IV after its phosphorylation and activation by a newly discovered brain CaM-kinase IV kinase. Our results show that activated CaM-kinase IV has the same Km (1-5 microM) for CREB phosphorylation, but the Vmax is about 30-fold higher than with non-activated CaM-kinase IV. Activated CaM-kinase IV still shows specificity for phosphorylation of Ser133, the site necessary for transactivation by CREB. It is likely that the lower efficiency of transcriptional activation by transfected CaM-kinase IV in previous studies was due to the fact that the CaM-kinase IV was not activated by CaM-kinase IV kinase.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Calcium / pharmacology
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • Calcium-Calmodulin-Dependent Protein Kinase Type 4
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
  • Calmodulin / pharmacology
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Enzyme Activation
  • Kinetics
  • Molecular Sequence Data
  • Peptide Mapping
  • Phosphorylation
  • Phosphoserine / metabolism
  • Protein-Serine-Threonine Kinases / metabolism*
  • Recombinant Proteins
  • Substrate Specificity

Substances

  • Calmodulin
  • Cyclic AMP Response Element-Binding Protein
  • Recombinant Proteins
  • Phosphoserine
  • Protein-Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • Calcium-Calmodulin-Dependent Protein Kinase Type 4
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Calcium