Bisindolylmaleimide I suppresses fibroblast growth factor-mediated activation of Erk MAP kinase in chondrocytes by preventing Shp2 association with the Frs2 and Gab1 adaptor proteins

J Biol Chem. 2007 Feb 2;282(5):2929-36. doi: 10.1074/jbc.M606144200. Epub 2006 Dec 4.

Abstract

Fibroblast growth factors (FGFs) inhibit chondrocyte proliferation via the Erk MAP kinase pathway. Here, we explored the role of protein kinase C in FGF signaling in chondrocytes. Erk activity in FGF2-treated RCS (rat chondrosarcoma) chondrocytes or human primary chondrocytes was abolished by the protein kinase C inhibitor bisindolylmaleimide I (Bis I). Bis I inhibited FGF2-induced activation of MEK, Raf-1, and Ras members of Erk signaling module but not the FGF2-induced tyrosine phosphorylation of Frs2 or the kinase activity of FGFR3, demonstrating that it targets the Erk cascade immediately upstream of Ras. Indeed, Bis I abolished the FGF2-mediated association of Shp2 tyrosine phosphatase with Frs2 and Gab1 adaptor proteins necessary for proper Ras activation. We also determined which PKC isoform is involved in FGF2-mediated activation of Erk. When both conventional and novel PKCs expressed by RCS chondrocytes (PKCalpha, -gamma, -delta, and -epsilon) were down-regulated by phorbol ester, cells remained responsive to FGF2 with Erk activation, and this activation was sensitive to Bis I. Moreover, treatment with PKClambda/zeta pseudosubstrate lead to significant reduction of FGF2-mediated activation of Erk, suggesting involvement of an atypical PKC.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • CHO Cells
  • Cell Line, Tumor
  • Chondrocytes / drug effects
  • Chondrocytes / physiology*
  • Cricetinae
  • Cricetulus
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Fibroblast Growth Factors / physiology*
  • Humans
  • Indoles / pharmacology*
  • Intracellular Signaling Peptides and Proteins / antagonists & inhibitors*
  • Maleimides / pharmacology*
  • Membrane Proteins / metabolism*
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatases / antagonists & inhibitors*
  • Rats

Substances

  • Adaptor Proteins, Signal Transducing
  • Enzyme Inhibitors
  • FRS2 protein, human
  • GAB1 protein, human
  • Indoles
  • Intracellular Signaling Peptides and Proteins
  • Maleimides
  • Membrane Proteins
  • Fibroblast Growth Factors
  • Extracellular Signal-Regulated MAP Kinases
  • PTPN11 protein, human
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatases
  • Ptpn11 protein, rat
  • bisindolylmaleimide I