Reduced Ca²⁺ mobilization and cell motility in Y567F, Y569F, and Y719F mutant cell lines.

(A) The schematic structure of murine KIT is shown with all tyrosine residue sites in the cytoplasmic region. The cytoplasmic domain contains 22 tyrosine residues. Extracellular indicates extracellular domain; Juxta, juxtamembrane domain; TK, tyrosine kinase domain; KI, kinase insert. (B) SCF-stimulated Ca²⁺ influx in 293T cells expressing WT or YF mutants. Cells were stimulated by 100 ng/mL SCF. Ca²⁺ influx was measured as described in Figure1. (C) SCF-stimulated cell migration in BAF3 cells expressing WT or YF mutants. Cell migration was induced by 30 ng/mL SCF. Data are shown as percentages of cells in lower chamber to the whole applied cells. The results are shown as the means ± SD of triplicate cultures. All experiments were repeated at least 3 times with similar results.