Ligand-Independent Activation of c-kit Receptor Tyrosine Kinase in a Murine Mastocytoma Cell Line P-815 Generated by a Point Mutation

• Published in: Blood Vol. 83; no. 9; pp. 2619 - 2626
• Main Authors: Tsujimura, Tohru, Furitsu, Takuma, Morimoto, Masahiro, Isozaki, Koji, Nomura, Shintaro, Matsuzawa, Yuji, Kitamura, Yukihiko, Kanakura, Yuzuru
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01-05-1994; The Americain Society of Hematology
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Blotting, Southern; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; DNA, Complementary - chemistry; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Mast-Cell Sarcoma - genetics; Mice; Molecular and cellular biology; Molecular Sequence Data; Phosphorylation; Phosphotyrosine; Point Mutation; Protein-Tyrosine Kinases - chemistry; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-kit; Receptor Protein-Tyrosine Kinases - genetics; Receptor Protein-Tyrosine Kinases - metabolism; Receptors, Colony-Stimulating Factor - genetics; Receptors, Colony-Stimulating Factor - metabolism; Transfection; Tumor Cells, Cultured; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Cell culture; Skin disease; Membrane receptor; Cell line; Animal; Point mutation; Mastocytoma; Activation; Benign neoplasm; Onc gene
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V83.9.2619.2619

The c-kit proto-oncogene encodes a receptor tyrosine kinase that is known to play a crucial role in hematopoiesis, especially in mast cell growth and differentiation. Although a number of dominant loss-of-function mutations of c-kit gene have been well characterized in mice, rats, and humans, little is known about the c-kit mutations contributing to ligand-independent activation of the c-kit receptor tyrosine kinase (KIT). In a murine mastocytoma cell line, P-815, KIT has been found to be constitutively phosphorylated on tyrosine and activated in a ligand-independent manner. Sequencing of the whole coding region of c-kit cDNA showed that c-kit cDNA of P-815 cells carries a point mutation in codon 814, resulting in amino acid substitution of Tyr for Asp. Murine wild-type c-kit cDNA and mutant-type c-kit cDNA encoding Tyr in codon 814 were expressed in cells of a human embryonic kidney cell line, 293T. In the transfected cells, mutant-form KITTyr814 was strikingly phosphorylated on tyrosine and activated in immune complex kinase reaction regardless of stimulation with a ligand for KIT (stem cell factor), whereas tyrosine phosphorylation and activation was barely detectable in wild-form KIT. The data presented here provide evidence for a novel activating mutation of c-kit gene that might be involved in neoplastic growth or oncogenesis of some cell types, including mast cells.