Peptidoglycan recognition proteins

Michel, T., et al., Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein, Nature. 414, 6865, 756, 2001. 

ITOH N, TAKAHASHI K G (2009), A novel peptidoglycan recognition protein containing a goose-type lysozyme domain from the Pacific oyster, Crassostrea gigas. Mol Immunol, 46,1768-1774. 

Fig. 2.2 Simplified schema of the prophenoloxidase activating (melanisation) cascade. Pattern recognition protein will, after binding to compounds (e.g. lipopolysaccharide, 3-l,3-glucans or peptidoglycans) typical for microorganisms, trigger activation of upstream components of serine proteinase cascade.The terminal proteinase will cleave prophenoloxidase to the catalytically active enzyme phenoloxidase. Different phenolic substances will give rise to melanin as well as toxic short-lived intermediates.

In addition to their important roles as stored fuels (starch, glycogen, dextran) and as structural materials (cellulose, chitin, peptidoglycans), polysaccharides and oligosaccharides are information carriers they serve as destination labels for some proteins and as mediators of specific cell-cell interactions and interactions between cells and the extracellular matrix. Specific carbohydrate-containing molecules act in cell-cell recognition and... 

Takenaka et al., 2004), this protein has also been reported to induce interleukin-6 production by macrophages via a TLR2-independent mechanism (Gobert et al., 2004). Recognition of H. pylori peptidoglycan-derived muropeptides by the intracellular pattern recognition molecule Nodi can occur (Viala et al., 2004) and contribute to the development of the subsequent inflammatory response. 

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