Figure 7.

Inhibition of BCR endocytosis does not block BCR-stimulated signaling. DKOS cells were grown with (CHC⁻) or without (CHC⁺) doxycycline for 96 h and pretreated with DMSO or latrunculin B. B cells were either not stimulated (−) or treated with 10 μg/ml goat anti-chicken IgM at 37°C for 10 and 30 min. Ten micrograms of lysate was resolved by electrophoresis and immunoblotted for phosphotyrosine (pTyr), CHC, unphosphorylated and phosphorylated ERK1 and ERK2, and actin. Only the ERK2 isoform is detected in DKOS cells.