Stimulation of RAR alpha activation function AF-1 through binding to the general transcription factor TFIIH and phosphorylation by CDK7

Cell. 1997 Jul 11;90(1):97-107. doi: 10.1016/s0092-8674(00)80317-7.

Abstract

The activity of the N-terminal activation function AF-1 of RAR alpha1 is abrogated upon mutation of a phosphorylatable serine residue (Ser-77). Recombinant RAR alpha was phosphorylated by a variety of proline-directed protein kinases in vitro. However, only the coexpression of cdk7 stimulated Ser-77 phosphorylation in vivo and enhanced transactivation by RAR alpha, but not by a S77A RAR mutant. Both free CAK (cdk7, cyclin H, MAT1) and the CAK-containing general transcription factor TFIIH phosphorylated Ser-77 in vitro. Furthermore RAR alpha bound free CAK and purified TFIIH in vitro, and RAR alpha-TFIIH complexes could be isolated from HeLa nuclear extracts. These findings represent the first example of activation of a transactivator through binding to and phosphorylation by a general transcription factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Cell Nucleus / metabolism
  • Cyclin-Dependent Kinases*
  • DNA Helicases / metabolism
  • Dimerization
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Phosphorylation
  • Point Mutation
  • Protein-Serine-Threonine Kinases / metabolism*
  • Receptors, Retinoic Acid / biosynthesis
  • Receptors, Retinoic Acid / chemistry
  • Receptors, Retinoic Acid / metabolism*
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Retinoic Acid Receptor alpha
  • Sequence Alignment
  • Serine
  • Trans-Activators / metabolism*
  • Transcription Factor TFIIH
  • Transcription Factors / metabolism*
  • Transcription Factors, TFII*
  • Transcriptional Activation
  • Transfection

Substances

  • RARA protein, human
  • Receptors, Retinoic Acid
  • Recombinant Fusion Proteins
  • Recombinant Proteins
  • Retinoic Acid Receptor alpha
  • Trans-Activators
  • Transcription Factors
  • Transcription Factors, TFII
  • Transcription Factor TFIIH
  • Serine
  • Protein-Serine-Threonine Kinases
  • Cyclin-Dependent Kinases
  • cyclin-dependent kinase-activating kinase
  • DNA Helicases