Activation of Akt by wild-type and oncogenic Kit depends on lipid rafts. (A) Effect of lipid rafts disruption on KL-mediated activation of Kit and Akt. Kit and Akt were immunoprecipitated from Mo7e cells that had been preincubated for 20 minutes in media containing the indicated concentration of MβCD and then stimulated with KL for 5 minutes. Immunoprecipitates were analyzed for tyrosine phosphorylation of Kit and phosphorylation of Akt at Ser⁴⁷³. Equal amounts of immunoprecipitated protein were verified by IB the same blots with antibodies against Kit and Akt. (B) Effect of lipid raft disruption on activation of Akt by oncogenic Kit in HMC-1 cells. Lysates from HMC-1 cells incubated in the absence or presence of 1 μM imatinib for 3 hours or in the presence of 1 mM MβCD for 3, 6, or 12 hours were separated by SDS/PAGE and analyzed with antibodies against phosphotyrosine, phosphorylated Akt (Ser⁴⁷³), and Akt.