ARF GTPases Function at the Golgi

ADP-ribosylation factors (ARFs) are small (~21 kDa) GTPases that play a central role in intracellular transport across eukaryotic cells. Structurally related to Ras GTPases, ARFs were initially discovered as allosteric activators of cholera toxin but later emerged as key regulators of membrane trafficking. ARFs function through a GDP-GTP cycle, where guanine nucleotide exchange factors (GEFs) promote the exchange of GDP for GTP, activating ARFs and facilitating their membrane association. Conversely, GTPase-activating proteins (GAPs) stimulate GTP hydrolysis, leading to ARF inactivation and membrane dissociation. This cycle is crucial for ARF-mediated recruitment of cargo adaptors, coat proteins which regulate cargo selection and trafficking pathways through a close interplay with lipid-based signaling.