ChlaDub1 of Chlamydia trachomatis suppresses NF-κB activation and inhibits IκBα ubiquitination and degradation

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes various human diseases, including blindness caused by ocular infection and sexually transmitted diseases resulting from urogenital infection. After infecting host cells, Chlamydiae avoid alarming the host's immune system. Among the immune evasion mechanisms, Chlamydiae can inhibit NF-kappa B activation, a crucial pathway for host inflammatory responses. In this study, we show that ChlaDub1, a deubiquitinating and deNeddylating protease from C. trachomatis, is expressed in infected cells. In transfection experiments, ChlaDub1 suppresses NF-kappa B activation induced by several pro-inflammatory stimuli and binds the NF-kappa B inhibitory subunit I kappa B alpha, impairing its ubiquitination and degradation. Thus, we provide further insight into the mechanism by which C. trachomatis may evade the host inflammatory response by demonstrating that ChlaDub1, a protease produced by this microorganism, is capable of inhibiting I kappa B alpha degradation and blocking NF-kappa B activation.