Acts as a GTPase-activating protein (GAP) toward guanine nucleotide exchange factors like ARL2, ARL3, ARF1 and ARF6, but not for GTPases outside the Arf family. Regulates IFN-related antiviral responses. Alveolar cells (morphologically type II cells) and alveolar macrophages (at protein level). Expressed in brain, colon, heart, kidney, liver, lung, muscle, placenta, small intestine, spleen, stomach and testis. In lung it is expressed in alveolar macrophages and alveolar walls.