Activating mutations of the c-kit proto-oncogene in a human mast cell leukemia cell line

Yuzuru Kanakura, Takuma Furitsu, Tohru Tsujimura, Joseph H. Butterfield, Leonie K. Ashman, Hirokazu Ikeda, Hitoshi Kitayama, Yoshio Kanayama, Yuji Matsuzawa, Yukihiko Kitamura

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45 Scopus citations


The c-kit proto-oncogene encodes a receptor tyrosine kinase that is known to play a crucial role in mast cell growth and differentiation. In a human mast cell leukemia cell line (HMC-1), KitR was found to be constitutively phosphorylated on tyrosine, activated and associated with phosphatidylinositol 3-kinase (PI3K) in the absence of autocrine production of SCF. Sequencing of c-kit cDNA revealed that c-kit genes of HMC-1 cells were composed of a normal, wild-type allele and a mutant allele with two point mutations in codon 560 and codon 816, resulting in intracellular amino acid substitutions of Gly-560 for Val and Val-816 for Asp, respectively. Murine c-kit mutants encoding Gly-559 and/or Val-814, corresponding to human Gly-560 and/or Val-816, were constructed by site-directed mutagenesis and expressed in cells of a human embryonic kidney cell line (293T). In the transfected cells, KitR (Gly-559 + Val-814) and KitR (Val-814) were strikingly phosphorylated on tyrosine and activated in the absence of SCF, whereas tyrosine phosphorylation and activation of KitR (Gly-559) or wild-type KitR was modest or little, respectively. These results suggest that constitutive activation of KitR in HMC-1 results from the activating mutations of c-kit gene, and raise the possibility that the activating mutations, particularly at codon 814 of murine c-kit or at codon 816 of human c-kit, may participate in oncogenesis of mast cells.

Original languageEnglish (US)
Pages (from-to)S18-S22
Issue numberSUPPL.1
StatePublished - 1994

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Cancer Research


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