Inhibition of transforming growth factor-beta signaling by low molecular weight compounds interfering with ATP- or substrate-binding sites of the TGF beta type I receptor kinase

Biochemistry. 2002 Sep 10;41(36):11000-7. doi: 10.1021/bi025936u.

Abstract

Transforming growth factor-beta (TGFbeta) is a potent regulator of cell proliferation, differentiation, apoptosis, and migration. TGF-beta type I receptor (TbetaR-I), which has intrinsic serine/threonine kinase activity, is a key component in activation of intracellular TGFbeta signaling. We studied two different classes of TbetaR-I inhibitors, i.e., compounds interfering with the ATP-binding site of the kinase and substrate-mimicking peptides. We found that pyridinylimidazole compounds inhibited TbetaR-I kinase at micromolar concentration. A representative compound, SB203580, inhibited in vivo Smad2 phosphorylation by TbetaR-I and affected TGFbeta-dependent transcriptional activation. Peptides mimicking the TbetaR-I phosphorylation sites at the C-terminus of Smad2 also inhibited the autophosphorylation of TbetaR-I and phosphorylation of Smad2 by TbetaR-I in vitro and in vivo, whereas a similar peptide from Smad5 was without effect. The substrate-mimicking peptide, fused to penetratin, inhibited a TGFbeta1-dependent transcriptional response in a luciferase reporter assay and ligand-dependent growth inhibition of Mv1Lu cells. Thus, the substrate-mimetic peptide is a new type of specific inhibitor of the TGFbeta signaling in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / pharmacology
  • Adenosine Triphosphate / antagonists & inhibitors
  • Adenosine Triphosphate / metabolism*
  • Amino Acid Sequence
  • Animals
  • Antennapedia Homeodomain Protein
  • Binding Sites / drug effects
  • COS Cells
  • Cell Line
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Homeodomain Proteins / pharmacology
  • Imidazoles / pharmacology
  • Mink
  • Molecular Mimicry
  • Molecular Sequence Data
  • Molecular Weight
  • Nuclear Proteins*
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / pharmacology
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Pyridines / pharmacology
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptors, Transforming Growth Factor beta / antagonists & inhibitors*
  • Receptors, Transforming Growth Factor beta / metabolism
  • Recombinant Fusion Proteins / chemical synthesis
  • Recombinant Fusion Proteins / pharmacology
  • Signal Transduction* / drug effects
  • Smad2 Protein
  • Smad3 Protein
  • Substrate Specificity
  • Trans-Activators / metabolism
  • Trans-Activators / pharmacology
  • Transcription Factors*
  • Transforming Growth Factor beta / antagonists & inhibitors*
  • Transforming Growth Factor beta / metabolism
  • Transforming Growth Factor beta / physiology*

Substances

  • Antennapedia Homeodomain Protein
  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • Homeodomain Proteins
  • Imidazoles
  • Nuclear Proteins
  • Peptide Fragments
  • Pyridines
  • Receptors, Transforming Growth Factor beta
  • Recombinant Fusion Proteins
  • Smad2 Protein
  • Smad3 Protein
  • Trans-Activators
  • Transcription Factors
  • Transforming Growth Factor beta
  • 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
  • Adenosine Triphosphate
  • Protein Serine-Threonine Kinases
  • Receptor, Transforming Growth Factor-beta Type I
  • SB 203580