CipA mediates complement resistance of Acinetobacter baumannii by formation of a factor I-dependent quadripartite assemblage.

ABSTRACT: Multidrug-resistant Acinetobacter baumannii is known to be one of the leading pathogens that cause severe nosocomial infections. To overcome eradication by the innate immune system during infection, A. baumannii developed a number of immune evasion strategies. Previously, we identified CipA as a plasminogen-binding and complement-inhibitory protein. Here we show that CipA inhibits all three complement activation pathways and interacts with key complement components C3, C3b, C4b, C5, Factor B, Factor D, and in particular Factor I. CipA also targets function of the C5 convertase as cleavage of C5 was impaired. Systematic screening of CipA variants identified two separate binding sites for C3b and a Factor I-interacting domain located at the C-terminus. Structure predictions usi

SUBMITTER: Ries JI 

PROVIDER: S-EPMC9361855 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature