Exo1 is an inhibitor of the exocytic pathway

Exo1 functions as a modifier of Golgi ARF1 GTPase activity, offering a unique approach to modulate Golgi function. Unlike agents like BFA, Exo1 targets a specific subset of membrane processes associated with the Golgi, presumably interacting with a different protein target, which could lead to distinct side effects. It disrupts vesicular traffic between the Endoplasmic Reticulum (ER) and the Golgi apparatus by altering Golgi structures, effectively inhibiting exocytosis with an IC50 value of approximately 20 μM. Furthermore, Exo1 impedes the acquisition of endoglycosidase H resistance in newly synthesized proteins, including VSVGts-GFP, transferrin, and MHC class I[1], indicative of its role in the intricate regulation of protein trafficking and modification.