ADP-ribosylation factor 1 (Arf1), when activated by guanine nucleotide exchange factors (ArfGEFs), plays a key role in regulating secretory traffic and membrane transport within the Golgi of eukaryotic cells. Golgicide A is a reversible inhibitor of the brefeldin A -resistant, cis-Golgi ArfGEF, GBF1 (IC50 = 3.3 μM). Inhibition of GBF1 via golgicide A can result in rapid dissociation of COPI vesicle coat protein from Golgi membranes and disassembly of the Golgi and trans-Golgi network. Golgicide A does not affect the association of the adaptor protein, AP-1, or the Arf1-binding protein, GCA3, with the trans-Golgi network nor does it interfere with the activity of the ArfGEFs, BIG1 or 2. Golgicide A can arrest the secretion of soluble and membrane-associated proteins at the ER-Golgi intermediate compartment, as well as prevent endocytic transport of Shiga toxin to the trans-Golgi network.
