Plays a role in the innate immune response. Binds to the lipid A moiety of bacterial lipopolysaccharides (LPS), a glycolipid present in the outer membrane of all Gram-negative bacteria (, ). Acts as an affinity enhancer for CD14, facilitating its association with LPS. Promotes the release of cytokines in response to bacterial lipopolysaccharide (, ).
Subcellular locations: Secreted, Cytoplasmic granule membrane
Membrane-associated in polymorphonuclear Leukocytes (PMN) granules.
Detected in blood serum (at protein level).