Figure 4

Bcr aggregates are degraded by a proteasome-dependent pathway. A) HPAECs were pretreated with 100 μM cystamine for 30 min, then incubated with 20 μM A23187 for 1 h. Cell lysates were subjected to Western blot analysis with the antibodies indicated to the left. B) After incubation with A23187 for 1 h, HPAECs were lysed and separated into Triton X-100 soluble (TX-soluble) or insoluble (TX-insoluble) fractions. The same amount of protein was subjected to Western blot for Bcr, TG2, or β-actin. C) HPAECs were pretreated with a proteasome inhibitor, MG132 (50 μM for 30 min), followed by incubation with the indicated concentrations of A23187. Antibodies used for Western blotting of lysates are indicated to the left. Asterisks, as in Figure 1.