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| Aliases | CFP, BFD, PFC, PFD, PROPERDIN, complement factor properdin, properdin | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM:300383;MGI:97545;HomoloGene:1969;GeneCards:CFP;OMA:CFP - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Properdin is aprotein that in humans is encoded by theCFP (complement factor properdin)gene.
Properdin is plasmaglycoprotein that activates thecomplement system of theinnate immune system. This protein binds to bacterial cell walls and dying human cells to stabilize theC3 andC5-convertase enzyme complexes to form anattack complex that leads to thelysis of the cell.
Properdin is a gammaglobulinprotein composed of multiple identical protein subunits with a separate ligand-binding site. Native properdin occurs in head-to-tail dimers, trimers and tetramers in the fixed ratio 22:52:28.[5]
It is known that it participates in some specificimmune responses. It plays a part intissueinflammation as well as the engulfing ofpathogens byphagocytes. In addition it is known to help to neutralize someviruses.
The properdin promotes the association ofC3b withFactor B and provides a focal point for the assembly of C3bBb on a surface. It binds to preformedalternative pathwayC3-convertases.[6] Properdin also inhibits theFactor H – mediated cleavage of C3b by Factor I.
The alternative pathway is not dependent onantibodies. This branch of the complement system is activated byIgA immune complexes and bacterialendotoxins,polysaccharides, andcell walls, and results in producinganaphylatoxins,opsonins,chemotactic factors, and themembrane attack complex, all of which help fight pathogens.
Properdin was discovered in 1954 by Dr.Louis Pillemer of the Institute of Pathology (now the Department of Pathology atCase Western Reserve University).
Properdin deficiency is a rareX-linked disease in which properdin is deficient. Affected individuals are susceptible to fulminantmeningococcal disease.[7]
