Editors' ChoiceImmunology

Detecting Gram-negative bacteria

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Science Signaling  16 Jun 2015:
Vol. 8, Issue 381, pp. ec163
DOI: 10.1126/scisignal.aac7821

Invariant molecules specific to different classes of microbes, but not expressed by eukaryotic cells, alert the immune system to a potential invader. Gaudet et al. identified one such molecule expressed by a variety of Gram-negative bacteria: the monosaccharide heptose-1,7-bisphosphate (HBP) (see the Perspective by Brubaker and Monack). HBP is an intermediate in the synthesis of lipopolysaccharide, a major component of bacterial cell walls. Rather than alerting the immune system through traditional pathogen detection pathways, such as Toll-like receptors, HBP signals through the host protein TIFA (TRAF-interacting protein with forkhead-associated domain), which activates both innate and adaptive immune responses to control the infection.

R. G. Gaudet, A. Sintsova, C. M. Buckwalter, N. Leung, A. Cochrane, J. Li, A. D. Cox, J. Moffat, S. D. Gray-Owen, Cytosolic detection of the bacterial metabolite HBP activates TIFA-dependent innate immunity. Science 348, 1251–1255 (2015). [Abstract] [Full Text]

S. W. Brubaker, D. M. Monack, Microbial metabolite triggers antimicrobial defense. Science 348, 1207–1208 (2015). [Summary] [Full Text]