HEK-Blue™ TLR4 cells are designed for studying the stimulation of TLR4 by monitoring the activation of NF-κB and AP-1.
TLR4, the first TLR identified, is the receptor for bacterial lipopolysaccharide (LPS) and lipid A, its toxic moiety .
However, TLR4 alone is not sufficient to confer LPS responsiveness. TLR4 requires MD-2, a secreted molecule, to functionally interact with LPS . Furthermore, a third protein, called CD14, was shown to participate in LPS signaling, leading to the activation of NF-κB and the production of proinflammatory cytokines .
1. Chow J. et al., 1999. Toll-like receptor-4 mediates lipopolysaccharide-induced signal transduction. J Biol Chem 274: 10689-92.
2. Shimazu R. et al., 1999. MD-2, a molecule that confers lipopolysaccharide responsiveness on Toll-like receptor 4. J Exp Med, 189(11): 1777-82.
3. Shuto T. et al., 2005. Membrane-anchored CD14 is required for LPS-induced TLR4 endocytosis in TLR4/MD-2/CD14 overexpressing CHO cells. Biochem Biophys Res Commun 338: 1402-9.