Required for proper surface expression of the autotransporter adhesin AtaA. Probably assists in the secretion of the passenger domain of AtaA from the periplasm to the extracellular environment across the cell outer membrane. Binds peptidoglycan. Monomer. Stably interacts with AtaA. Associates with the outer membrane in wild-type cells, if the ataA gene is deleted it is found in the periplasm. Part of the ataA-tpgA operon. Decreases adhesiveness of cells to polystyrene. No change in the amount of AtaA associated with the cell outer membrane, but greatly reduced amounts of correctly targeted AtaA; significantly decreased AtaA immunofluorescence and nanofibers on the cell surface, and greatly increased amounts of AtaA passenger domain in the periplasm. No visible change in the amount of Omp38 in the outer membrane.