Temporal regulation of Salmonella virulence effector function by proteasome-dependent protein degradation

摘要: Salmonella enterica invasion of host cells requires the reversible activation Rho-family GTPases Cdc42 and Rac1 by bacterially encoded GEF SopE GAP SptP, which exert their function at different times during infection are delivered into a type III secretion system. We found that SptP in equivalent amounts early infection. However, is rapidly degraded through proteosome-mediated pathway, while exhibits much slower degradation kinetics. The half-lives these effector proteins determined translocation domains. Chimeric protein analysis indicated delivery domain drastically shortened its half-life. Conversely, signals significantly increased half-life, resulting persistent actin cytoskeleton rearrangements. This regulatory mechanism constitutes remarkable example pathogen's adaptation to modulate cellular functions.