Protein kinase-A dependent phosphorylation of transcription enhancer factor-1 represses its DNA-binding activity but enhances its gene activation ability

Nucleic Acids Res. 2000 Aug 15;28(16):3168-77. doi: 10.1093/nar/28.16.3168.

Abstract

The cAMP-dependent signaling pathway has been implicated in cardiac cell growth/differentiation and muscle gene transcription. Previously, we have identified a cAMP-inducible E-box/M-CAT hybrid motif in the cardiac alpha-myosin heavy chain (alpha-MHC) gene promoter. The two factors, TEF-1 and Max, that bind to this motif are found to physically associate with each other and exert a positive cooperative effect for gene regulation. Here we show that TEF-1, but not Max, is a substrate for protein kinase-A (PK-A)-dependent phosphorylation. TEF-1 is phosphorylated by PK-A at residue serine-102. This post-translational modification of TEF-1 repressed its DNA-binding activity, but not its ability to interact with the Max protein. Replacement of serine-102 in TEF-1 by a neutral or a charged amino acid did not abolish its DNA-binding ability, suggesting that changing a charge at the 102 amino-acid position of TEF-1 was not sufficient to inhibit its DNA-binding activity. We also show that PK-A response of the alpha-MHC gene is stimulated by the presence of wild-type TEF-1 but not by mutant TEF-1 having serine-102 replaced by alanine, suggesting that phosphorylation at this residue accounts for the cAMP/PK-A response of the gene. Thus, these data demonstrate that TEF-1 is a direct target of cAMP/PK-A signaling in cardiac myocytes.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Basic-Leucine Zipper Transcription Factors
  • Cell Nucleus / metabolism
  • Cells, Cultured
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Fetus
  • Gene Expression Regulation*
  • Glutathione Transferase / genetics
  • Humans
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Myocardium / cytology
  • Myocardium / metabolism
  • Nuclear Proteins*
  • Phosphorylation
  • Rats
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Serine / metabolism
  • Transcription Factors / chemistry
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation
  • Transfection

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Basic-Leucine Zipper Transcription Factors
  • DNA-Binding Proteins
  • MAX protein, human
  • Max protein, rat
  • Myc associated factor X
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • TEAD1 protein, human
  • Transcription Factors
  • Max protein, mouse
  • Serine
  • Glutathione Transferase
  • Cyclic AMP-Dependent Protein Kinases