Activation of AKT, ERK, IKKα/β, JNK, and p38 MAPK after BCR stimulation with sol- and imm-IgM. Immunoblot analysis is shown for one CLL case with unmutated (G31) and one case with mutated (G19) V_H genes. Stimulation was done with sol-IgM for 15 minutes, 45 minutes, and 20 hours, and with imm-IgM for 45 minutes and 20 hours, as described in “Patients, materials, and methods.” Stimulation with PMA (1 μM) was used as a positive control. The antibodies against the phosphorylated and total proteins used for immunoblotting are indicated on the left.