Expression of two types of neurofibromatosis type 1 gene transcripts in gastric cancers and comparison of GAP activities

Biochem Biophys Res Commun. 1992 Aug 31;187(1):332-9. doi: 10.1016/s0006-291x(05)81497-4.


To understand the molecular mechanism of gastric tumorigenesis, the status of neurofibromatosis type 1 (NF1) gene was analyzed in human gastric cancer cell lines. Although the sequencing of the GTPase activating protein (GAP)-related region of NF1 (NF1-GRD) revealed no apparent mutation, the NF1-GRD transcript (type I) and that containing an additional 63 bp insert in the center of NF1-GRD (type II) were equally expressed in most gastric cancer cells. By contrast, type II was predominantly expressed in normal stomach mucosa. When these two types of NF1-GRD were bacterially expressed and their GAP activities were tested, both types of NF1-GRD similarly stimulated ras GTPase activity. However, arachidonic acid inhibited GAP activities of two types of NF1-GRD to different extents. These results suggest that the increased expression of type I NF1 protein may modulate ras-related signal transduction and it may be related to the control of the gastric cellular proliferation.

Publication types

  • Comparative Study

MeSH terms

  • Arachidonic Acid / pharmacology
  • Base Sequence
  • DNA / chemistry
  • DNA / genetics
  • GTPase-Activating Proteins
  • Gastric Mucosa / metabolism
  • Gene Expression*
  • Genes, Neurofibromatosis 1 / genetics*
  • Humans
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Proteins / chemistry
  • Proteins / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Fusion Proteins / pharmacology
  • Sequence Homology, Nucleic Acid
  • Signal Transduction
  • Stomach Neoplasms / genetics*
  • Transcription, Genetic*
  • ras GTPase-Activating Proteins


  • GTPase-Activating Proteins
  • Proteins
  • Recombinant Fusion Proteins
  • ras GTPase-Activating Proteins
  • Arachidonic Acid
  • DNA