CD14 is a glycosylphosphatidylinositol (GPI)-anchored membrane protein which acts as a bacterial pattern recognition receptor .
CD14 is found on cells derived from the monocyte/macrophage lineage, as well as neutrophils and B lymphocytes.
CD14 serves as a member of the heteromeric lipopolysaccharide (LPS) receptor complex that also contains TLR4 and MD2 .
CD14 binds LPS but is not capable of initiating a transmembrane activation signal since it does not contain a cytoplasmic domain.
Upon LPS binding, CD14 physically associates with TLR4 which in turn transduces the signal. CD14 was also shown to interact with TLR2 in response to various microbial infections .
Pugin J. et al., 1994. CD14 is a pattern recognition receptor. Immunity. 1(6):509-16.
Da Silva Correia J. et al., 2001. Lipopolysaccharide is in close proximity to each of the proteins in its membrane receptor complex. transfer from CD14 to TLR4 and MD-2. J Biol Chem. 276(24): 21129-35.
Aderem A. & Ulevitch R.J. , 2000. Tolllike receptors in the induction of the innate immune response. Nature. 406(6797):782-7.