FIGURE 1.

BFA dismantles the Golgi by inhibiting ARF1 activation. A1–A4, immunostaining of pancreatic acini with antibodies against the Golgi marker, P115 (shown in green) and actin (shown in red) under basal conditions (A1) or treated with 100 nm caerulein (CER) alone for 15 min (A2); 50 μm BFA for 2 h (A3); or BFA followed by CER treatment (A4). These changes demonstrate that BFA dismantles the Golgi without causing major changes in actin distribution. Arrows indicate basal relocation of the F-actin. Note that BFA did not prevent caerulein-induced blebbing (A2 and A4). A and B, WBs of ARF1 (A) and ARF6 (B) pulldowns from pancreatic acini after treatment with 100 nm CER at the indicated times show basal activity (Bas) and an increase in ARF1 but not ARF6 activation. BFA (50 μm) blocks CER-induced ARF1 activation (+BFA, 1B). C, no activation of ARF6 was noted. The positive control GTPγS, but not GDP, induces both ARF1 and ARF6 activation.