Salmonella outer membrane protein A (OmpA) (OmpA)

Salmonella outer membrane protein A (OmpA) is a major β-barrel porin in the outer membrane of Salmonella Typhimurium and other Salmonella species, facilitating selective diffusion of ions and solutes while anchoring the outer membrane to the peptidoglycan layer. It plays critical roles in bacterial pathogenesis by protecting against phagocytosis, promoting survival within host macrophages, and maintaining outer membrane integrity against nitrosative and oxidative stresses. OmpA deletion leads to upregulated expression of other porins like OmpC, OmpD, and OmpF, increasing membrane permeability and susceptibility to host defenses, as well as downregulation of SPI-2 effector proteins like SifA and SsaV, causing escape from the Salmonella-containing vacuole (SCV) into the cytosol where bacteria are killed. In infection, OmpA enables adaptation to the acidic phagosome environment, supports SCV stability via LAMP-1 colocalization, and provides SPI-2-independent protection from reactive nitrogen intermediates. As a virulence factor, OmpA contributes to salmonellosis by enhancing intracellular replication and resisting antimicrobial effectors, positioning it as a potential therapeutic target for disrupting Salmonella infections, though no direct drugs are noted.

Other names

outer membrane porin A