CD14

CD14 is a leucine-rich-repeat glycoprotein expressed mainly by monocytes and macrophages (weakly by granulocytes). It exists as a glycosylphosphatidylinositol-anchored protein on the outer leaflet of the plasma membrane, concentrated in lipid rafts, and as a soluble form in plasma and other body fluids produced by release of the anchored protein or secretion of an anchor-less form. Its bent LRR solenoid carries an amino-terminal hydrophobic pocket that binds acylated microbial molecules. CD14 accepts monomeric bacterial lipopolysaccharide (LPS) from LPS-binding protein (LBP) and transfers it to the TLR4-MD-2 complex, forming with TLR4 and MD-2 the LPS receptor complex; it similarly delivers di- and triacylated lipopeptides to TLR2-TLR6 and TLR2-TLR1 heterodimers and binds lipoteichoic acid and peptidoglycan. Because it lacks a transmembrane and cytoplasmic domain, CD14 does not itself transmit signals across the membrane, but it greatly sensitises cells to low ligand concentrations. Membrane CD14 is also required for LPS-induced TLR4 dimerization and for Syk/PLCgamma2-dependent endocytosis of TLR4, which enables TRIF-dependent interferon production from endosomes. Soluble CD14 confers LPS responsiveness on CD14-negative cells such as epithelial and endothelial cells. CD14 also binds apoptotic cells and mediates their recognition and clearance by macrophages without triggering inflammation. Mice lacking CD14 are resistant to endotoxic shock.

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.