Plays a role in constitutive metalloproteinase (MMP) secretion from the trans Golgi network (PubMed:26507660). May have important functions during vesicle biogenesis at certain cargo subdomains, which could be predominantly utilized by secreted MMPs, such as MMP7 and MMP2 (PubMed:26507660). Also involved in autophagy by regulating the starvation-dependent trafficking of ATG9A vesicles which deliver the phosphatidylinositol 4-kinase beta (PI4KB) to the autophagosome initiation site (PubMed:31204568, PubMed:30917996). Involved in phagophore growth during mitophagy by regulating ATG9A trafficking to mitochondria (PubMed:33773106). In addition, plays a role in NF-kappa-B inhibition by interacting with IKBKB and IKBKG (PubMed:26296658). Forms homodimers or heterodimers with ARFIP1 (PubMed:21239483). Interacts with RAC1 (PubMed:11346801). Specifically binds to GTP-bound ARF1 and ARF6, but binds to RAC1.GTP and RAC1.GDP with similar affinities. Interacts with ARL1 (PubMed:11303027, PubMed:22679020, PubMed:26507660). Interacts (via N-terminus) with IKBKB and IKBKG; these interactions inhibit activation of NF-kappa-B (PubMed:26296658).