Wild-type (+/+) and calpain-1 null (−/−) BMMCs were sensitized with anti-TNP IgE and stimulated with TNP-BSA for various times. Total cell lysates were analyzed by Western blotting for various phosphorylated and total proteins. A–B, Decrease IκB phosphorylation in calpain-1 null BMMCs was found at 5 min after TNP stimulation when compared with that in wild-type cells. Data are mean ± SEM. n = 3 cultures of BMMCs, **p< 0.01 by comparison with calpain-1 null BMMCs. C, The pattern of TNP-induced phosphorylation of Erk1/2, p38, JNK, Akt, and GSK3β is similar between wild-type and calpain-1 null BMMCs.