Research ArticleHost-Pathogen Interactions

The adhesion GPCR BAI1 mediates macrophage ROS production and microbicidal activity against Gram-negative bacteria

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Science Signaling  02 Feb 2016:
Vol. 9, Issue 413, pp. ra14
DOI: 10.1126/scisignal.aac6250

Bacteria come to a sticky end

Pattern recognition receptors (PRRs) detect microbial products and stimulate the innate immune response to infections. BAI1 is a G protein–coupled receptor of the adhesion GPCR family and is also a PRR that binds to lipopolysaccharide on the surface of Gram-negative bacteria to facilitate their internalization by macrophages. Billings et al. found that BAI1 triggered the killing of the internalized bacteria by stimulating the production of reactive oxygen species. When engaged by bacteria, BAI1 activated Rac1 to stimulate the activity of the NADPH oxidase complex Nox2 in macrophages. Mice deficient in BAI1 were inefficient at clearing Gram-negative bacteria and were likely to die from the infection. Together, these data suggest that BAI1 connects bacterial internalization with their killing.

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