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VapA of Rhodococcus equi binds phosphatidic acid
Author(s) -
Wright Lindsay M.,
Carpi Emily M.,
Bennett Terry L.,
Hondalus Mary K.,
Starai Vincent J.
Publication year - 2018
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13892
Subject(s) - rhodococcus equi , biology , virulence , microbiology and biotechnology , intracellular parasite , intracellular , pathogen , phagosome , virology , phagocytosis , gene , genetics
Summary Rhodococcus equi is a multihost, facultative intracellular bacterial pathogen that primarily causes pneumonia in foals less than six months in age and immunocompromised people. Previous studies determined that the major virulence determinant of R. equi is the surface bound virulence associated protein A (VapA). The presence of VapA inhibits the maturation of R. equi ‐containing phagosomes and promotes intracellular bacterial survival, as determined by the inability of vapA deletion mutants to replicate in host macrophages. While the mechanism of action of VapA remains elusive, we show that soluble recombinant VapA 32‐189 both rescues the intramacrophage replication defect of a wild type R. equi strain lacking the vapA gene and enhances the persistence of nonpathogenic Escherichia coli in macrophages. During macrophage infection, VapA was observed at both the bacterial surface and at the membrane of the host‐derived R. equi containing vacuole, thus providing an opportunity for VapA to interact with host constituents and promote alterations in phagolysosomal function. In support of the observed host membrane binding activity of VapA, we also found that rVapA 32‐189 interacted specifically with liposomes containing phosphatidic acid in vitro . Collectively, these data demonstrate a lipid binding property of VapA, which may be required for its function during intracellular infection.