Membrane protein was extracted from A549 cells transduced with adenoviral vectors expressing WT-ABCA3 or ABCA3 variant constructs encoding p.Asn140His, p.Phe1203del, p.Ser1262Gly, p.Val1399Met, or p.Glu292Val (previously characterized type II mutant). ATPase activity was measured as free phosphate (Pi) released as percentage of WT activity and normalized to Western blot with anti-GFP antibody. Mutant proteins p.Asn140His, p.Phe1203del, p.Ser1262Gly, and p.Val1399Met had decreased ATPase activity as compared to WT-ABCA3. Similar to previous results, p.Glu292Val had reduced ATPase activity as compared to WT-ABCA3.*p<0.001