Activates the ARF proteins by exchanging bound GDP for free GTP. Plays a role in maintaining mitochondrial morphology, and in the turnover of mitochondria through mitophagy (PubMed:25190516). Interacts with GMH1. Interacts (via N-terminal region) with SEC21 (via C-terminus). Soluble and partially membrane-bound. The SEC7 domain is sufficient for stimulation of nucleotide exchange on myristoylated yeast ARF2. Present with 2940 molecules/cell in log phase SD medium.