Properdin

CFP
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	1W0R, 1W0S
Identifiers
Aliases	CFP, BFD, PFC, PFD, PROPERDIN, complement factor properdin, properdin
External IDs	OMIM: 300383; MGI: 97545; HomoloGene: 1969; GeneCards: CFP; OMA:CFP - orthologs
Gene location (Human)
Chr.	X chromosome (human)
End	47,630,305 bp
Gene location (Mouse)
Chr.	X chromosome (mouse)
End	20,797,794 bp
RNA expression pattern
	Top expressed in
	granulocyte; ; monocyte; ; blood; ; spleen; ; bone marrow; ; bone marrow cells; ; gonad; ; appendix; ; lymph node; ; right lung;
	Top expressed in
	granulocyte; ; stroma of bone marrow; ; spleen; ; mesenteric lymph nodes; ; ankle joint; ; right lobe of liver; ; axillary lymph node; ; white adipose tissue; ; tibiofemoral joint; ; thymus;
	More reference expression data
	n/a
Gene ontology
Molecular function	protein binding; serine-type endopeptidase activity;
Cellular component	extracellular matrix; endoplasmic reticulum lumen; extracellular region; extracellular space; specific granule lumen; tertiary granule lumen; collagen-containing extracellular matrix;
Biological process	immune response; regulation of complement activation; defense response to bacterium; immune system process; complement activation; protein O-linked fucosylation; complement activation, alternative pathway; innate immune response; neutrophil degranulation; proteolysis;
	Sources:Amigo / QuickGO
Orthologs
	5199
	18636
	ENSG00000126759
	ENSMUSG00000001128
	P27918
	P11680
	NM_002621; NM_001145252
	NM_008823
	NP_001138724; NP_002612
	NP_032849
	Wikidata
View/Edit Human	View/Edit Mouse

Properdin or Factor P is the only known positive regulator of complement activation that stabilizes the alternative pathway convertases. It is found in the blood serum of more complex animals.

Structure

Properdin is a gamma globulin protein 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]

Function

It is known that it participates in some specific immune responses. It plays a part in tissue inflammation as well as the engulfing of pathogens by phagocytes. In addition it is known to help to neutralize some viruses.

The properdin promotes the association of C3b with Factor B and provides a focal point for the assembly of C3bBb on a surface. It binds to preformed alternative pathway C3-convertases.^[6] Properdin also inhibits the Factor H – mediated cleavage of C3b by Factor I.

The alternative pathway is not dependent on antibodies. This branch of the complement system is activated by IgA immune complexes and bacterial endotoxins, polysaccharides, and cell walls, and results in producing anaphylatoxins, opsonins, chemotactic factors, and the membrane attack complex, all of which help fight pathogens.

History

Properdin was discovered in 1954 by Dr. Louis Pillemer of the Institute of Pathology (now the Department of Pathology at Case Western Reserve University).

Deficiency

Properdin deficiency is a rare X-linked disease in which properdin is deficient. Affected individuals are susceptible to fulminant meningococcal disease.^[7]

External links

Properdin at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

^ ^a ^b ^c GRCh38: Ensembl release 89: ENSG00000126759 – Ensembl, May 2017
^ ^a ^b ^c GRCm38: Ensembl release 89: ENSMUSG00000001128 – Ensembl, May 2017
^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ Smith C, Pangburn M, Vogel CW, Müller-Eberhard H (1984). "Molecular Architecture of Human Properdin, a Positive Regulator of the Alternative Pathway of Complement". J Biol Chem. 259: R4582-4588.
^ Hourcade D (2006). "The Role of Properdin in the Assembly of the Alternative Pathway C3 Convertases of Complement". J Biol Chem. 281: R2128-2132. doi:10.1074/jbc.m508928200.{{cite journal}}: CS1 maint: unflagged free DOI (link)
^ Dr. Lars Otto Uttenthal Properdin September 01 2005

[refGRCh38Ensembl-1] GRCh38: Ensembl release 89: ENSG00000126759 – Ensembl, May 2017

[refGRCm38Ensembl-2] GRCm38: Ensembl release 89: ENSMUSG00000001128 – Ensembl, May 2017

[3] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[4] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[5] Smith C, Pangburn M, Vogel CW, Müller-Eberhard H (1984). "Molecular Architecture of Human Properdin, a Positive Regulator of the Alternative Pathway of Complement". J Biol Chem. 259: R4582-4588.

[6] Hourcade D (2006). "The Role of Properdin in the Assembly of the Alternative Pathway C3 Convertases of Complement". J Biol Chem. 281: R2128-2132. doi:10.1074/jbc.m508928200.{{cite journal}}: CS1 maint: unflagged free DOI (link)

[7] Dr. Lars Otto Uttenthal Properdin September 01 2005

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