Dose and time response of KIT and phosphorylated KIT protein to 17-AAG in HMC-1.1 and HMC-1.2 cells. (A) Mast cells were incubated with increasing concentrations of 17-AAG for 8 hours, and levels of KIT protein (i-ii), phosphorylated KIT protein (iii-iv), and tubulin (v-vi) were measured as described in “Patients, materials, and methods.” (B) Mast cells were incubated for increasing time intervals with 1 μM 17-AAG and levels of KIT protein (i-ii), phosphorylated KIT protein (iii-iv), and tubulin (v-vi) were measured as described in “Patients, materials, and methods.” Tubulin protein was measured to confirm that equal amounts of total protein were added in each lane.