GTP-binding protein involved in protein trafficking among different compartments. Modulates vesicle budding and uncoating within the Golgi complex. Deactivation induces the redistribution of the entire Golgi complex to the endoplasmic reticulum, suggesting a crucial role in protein trafficking. In its GTP-bound form, its triggers the association with coat proteins with the Golgi membrane. The hydrolysis of ARF1-bound GTP, which is mediated by ARFGAPs proteins, is required for dissociation of coat proteins from Golgi membranes and vesicles. The GTP-bound form interacts with PICK1 to limit PICK1-mediated inhibition of Arp2/3 complex activity; the function is linked to AMPA receptor (AMPAR) trafficking, regulation of synaptic plasicity of excitatory synapses and spine shrinkage during long-term depression (LTD). Interacts (when activated) with GGA1, GGA2 and GGA3; the interaction is required for proper subcellular location of GGA1, GGA2 and GGA3 (By similarity). Interacts with ARHGAP21, ASAP2, GGA1, HERC1, PRKCABP, PIP5K1B, TMED2, PSCD2, TMED10 and GRIA2 (PubMed:11703931, PubMed:14654833). Interacts with ARFGAP1, which hydrolyzes GTP and thus, regulates its function. Interacts with PI4KB in the Golgi complex. Interacts with NCS1/FREQ in the Golgi and at the plasma membrane. Interacts with PLEKHA3. Interacts with PLEKHA8; the interaction, together with phosphatidylinositol 4-phosphate binding, is required for FAPP2-mediated glucosylceramide transfer activity. Interacts (activated) with PICK1 (via PDZ domain); the interaction blocks Arp2/3 complex inhibition (By similarity). Interacts with IQSEC1 (PubMed:24058294). Interacts with C9orf72 (By similarity). Belongs to the small GTPase superfamily. Arf family.