Comparison of KL-mediated gene expression profiles in wt and wasp^−/− BMMCs indicates a profound genetic effect through Kit-WASP signaling. Wt or WASP-deficient BMMCs were mock treated or stimulated with KL (500 ng/mL) for 12 hours in replicates (n = 4, wt; n = 3, wasp^−/−). Gene expression analysis was performed and analyzed, as described in “Gene expression profiling.” The effects of WASP on the Kit gene expression profile were either independent, permissive (up- or down-regulation requiring the presence of WASP), or blocking (up- or down-regulation only in the absence of WASP; A, Venn diagram and B, heat map). The Venn diagram was generated comparing genes with a fold-change cutoff of 2 for up-regulated and 0.5 for down-regulated genes. Two heat maps with selected genes that encode for proteins with either actin- or Ca²⁺-binding function are shown (C). Heat map shows the relative expression levels of selected survival/apoptosis-related genes of wt or WASP-deficient BMMCs when exposed to KL (D).