Interaction of MAPKs and Ca²⁺ influx in KIT signal transduction.

(A) Effects of MEK1/2 inhibitor and p38 MAPK inhibitor on SCF-induced Ca²⁺ influx. BAF3/KIT cells were loaded with Indo 1-AM and incubated with or without U0126 or SB203580 at the indicated concentration for 30 minutes at 37°C. The intracellular Ca²⁺ concentration was monitored by measuring the relative fluorescence using a spectrofluorometer. (B) Effects of BAPTA-AM on SCF-induced MEK1/2 and p38 MAPK phosphorylation by Western blot analysis. BAF3/KIT cells were incubated with or without 10 μM BAPTA-AM for 30 minutes and then stimulated with 100 ng/mL SCF in the presence of the inhibitors. Similar results were obtained from 3 independent experiments.