Effect of stem cell factor (SCF) treatment on tyrosine phosphorylation of wild-type Kit and mutant Kit isoforms stably expressed in Chinese hamster ovary cells. Chinese hamster ovary cells stably transfected with wild-type (WT) or mutant KIT isoforms were stimulated with single serial dilutions of stem cell factor, and Kit phosphorylation was assessed. For mutant Kit isoforms, data are expressed as the percentage of vehicle control. For wild-type Kit, data are expressed as the percentage of phosphorylation observed following stimulation with 300 ng/mL SCF. The results of a single experiment are shown.