Important for biofilm formation, binding to various extracellular matrix/basal membrane (ECM/BM) proteins, adhesion to collagen type IV, and for survival in a mouse model of lethal infection. Homotrimer. The C-terminal translocator domain is localized in the outer membrane and the passenger domain is at the cell surface. Expression is growth phase dependent. Expressed at high levels during early logarithmic phase, and expression declines throughout the logarithmic and stationary phases. The signal peptide, cleaved at the inner membrane, guides the autotransporter protein to the periplasmic space. Then, insertion of the C-terminal translocator domain in the outer membrane forms a hydrophilic pore for the translocation of the passenger domain to the bacterial cell surface. Deletion decreases biofilm formation and decreases the virulence in the murine model of lethal infection. Might be a good vaccine candidate. The ability of Ata to engender anti-adhesive, bactericidal, opsonophagocytic, and protective antibodies validates its potential use as an antigenic target against multidrug-resistant A.baumannii infections. Belongs to the autotransporter-2 (AT-2) (TC 1.B.40) family.