The Kit-activating mutation D816V enhances stem cell factor--dependent chemotaxis.
The D816V mutation of c-kit has been detected in patients with mastocytosis. This mutation leads to constitutive tyrosine kinase activation of Kit. Because stem cell factor (SCF), the ligand for Kit (CD117(+)), is a chemoattractant for CD117(+) cells and one feature of mastocytosis is an abnormal collection of mast cells in tissues derived from CD34(+)CD117(+) mast cell precursors, the hypothesis was considered that the D816V mutation would enhance chemotaxis of these precursor cells. Constructs encoding wild-type Kit or Kit bearing the D816V mutation were transfected into Jurkat cells, labeled with Calcein-AM, and migration to SCF assessed in the presence or absence of tyrosine kinase inhibitors. Chemotaxis to SCF was enhanced in D816V transfectants compared to wild-type Kit transfectants (P <.002). Migration of both transfectants was inhibited by tyrosine kinase inhibitors, although D816V transfectants were more sensitive. Chemotaxis was next performed on CD34(+)CD117(+) circulating mast cell precursors obtained from patients with mastocytosis. Analysis of prechemotaxis and migrated cells showed that whereas less than 10% in the prechemotaxis sample had the D816V mutation, 40% to 80% of migrated cells had this mutation. These results demonstrate that the D816V Kit mutation enhances chemotaxis of CD117(+) cells, offering one explanation for increased mast cells observed in tissues of patients with mastocytosis. (Blood. 2001;98:1195-1199)
Taylor
M L
ML
Laboratory of Allergic Diseases and Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1881, USA. mtaylor@niaid.nih.gov
Dastych
J
J
Sehgal
D
D
Sundstrom
M
M
Nilsson
G
G
Akin
C
C
Mage
R G
RG
Metcalfe
D D
DD
D018952:Antigens, CD34; D002633:Chemotaxis / Q000187:drug effects* / Q000235:genetics; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D008415:Mastocytosis / Q000209:etiology* / Q000235:genetics / Q000473:pathology; D020125:Mutation, Missense; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism; D019089:Stem Cell Factor / Q000494:pharmacology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D018952:Antigens, CD34; D004791:Enzyme Inhibitors; D019089:Stem Cell Factor; D011505:Protein-Tyrosine Kinases; D019009:Proto-Oncogene Proteins c-kit