UniProt functional annotation for P27918



	UniProt functional annotation for P27918

UniProt code: P27918.

Organism: Homo sapiens (Human).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.

Function: A positive regulator of the alternate pathway (AP) of complement (PubMed:20382442, PubMed:28264884). It binds to and stabilizes the C3- and C5-convertase enzyme complexes (PubMed:20382442, PubMed:28264884). Inhibits CFI-CFH mediated degradation of Complement C3 beta chain (C3b) (PubMed:31507604). {ECO:0000269|PubMed:20382442, ECO:0000269|PubMed:28264884, ECO:0000269|PubMed:31507604}.

Subunit: In plasma, properdin exists as dimers, trimers or tetramers in the relative proportions of 26:54:20 (PubMed:20382442, PubMed:15491616, PubMed:28264884, PubMed:31507604). Interacts with the pro-C3-convertase enzyme complex (C3b-Bb) comprised of Complement C3 beta chain (C3b) and the Complement factor B Bb fragment (Bb), where it binds (via its TSP type-1 5 domain) with C3b and Bb (PubMed:28264884, PubMed:31507604). This interaction stabilizes the complex and allows it to become the active C3-convertase enzyme complex (C3b-Bb-FP) (PubMed:28264884, PubMed:31507604). Interacts with C3b (PubMed:28264884, PubMed:31507604). Interacts with CFB (PubMed:31507604). {ECO:0000269|PubMed:15491616, ECO:0000269|PubMed:20382442, ECO:0000269|PubMed:28264884, ECO:0000269|PubMed:31507604}.

Subcellular location: Secreted {ECO:0000269|PubMed:28264884, ECO:0000269|PubMed:31507604}.

Domain: TSP type-1 domain 0 binds to TSP type-1 domain 4, and TSP type- 1 domain 1 binds to TSP type-1 domain 6 (PubMed:15491616, PubMed:28264884, PubMed:31507604). These interactions mediate multimerization (PubMed:15491616, PubMed:28264884, PubMed:31507604). {ECO:0000269|PubMed:15491616, ECO:0000269|PubMed:28264884, ECO:0000269|PubMed:31507604}.

Disease: Properdin deficiency (PFD) [MIM:312060]: Results in higher susceptibility to bacterial infections; especially to meningococcal infections. Three phenotypes have been reported: complete deficiency (type I), incomplete deficiency (type II), and dysfunction of properdin (type III). {ECO:0000269|PubMed:10909851, ECO:0000269|PubMed:28264884, ECO:0000269|PubMed:31507604, ECO:0000269|PubMed:8871668, ECO:0000269|PubMed:9710744}. Note=The disease is caused by variants affecting the gene represented in this entry.

Annotations taken from UniProtKB at the EBI.


Organism:		Homo sapiens (Human).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.



Function:		A positive regulator of the alternate pathway (AP) of complement (PubMed:20382442, PubMed:28264884). It binds to and stabilizes the C3- and C5-convertase enzyme complexes (PubMed:20382442, PubMed:28264884). Inhibits CFI-CFH mediated degradation of Complement C3 beta chain (C3b) (PubMed:31507604). {ECO:0000269\|PubMed:20382442, ECO:0000269\|PubMed:28264884, ECO:0000269\|PubMed:31507604}.


Subunit:		In plasma, properdin exists as dimers, trimers or tetramers in the relative proportions of 26:54:20 (PubMed:20382442, PubMed:15491616, PubMed:28264884, PubMed:31507604). Interacts with the pro-C3-convertase enzyme complex (C3b-Bb) comprised of Complement C3 beta chain (C3b) and the Complement factor B Bb fragment (Bb), where it binds (via its TSP type-1 5 domain) with C3b and Bb (PubMed:28264884, PubMed:31507604). This interaction stabilizes the complex and allows it to become the active C3-convertase enzyme complex (C3b-Bb-FP) (PubMed:28264884, PubMed:31507604). Interacts with C3b (PubMed:28264884, PubMed:31507604). Interacts with CFB (PubMed:31507604). {ECO:0000269\|PubMed:15491616, ECO:0000269\|PubMed:20382442, ECO:0000269\|PubMed:28264884, ECO:0000269\|PubMed:31507604}.
Subcellular location:		Secreted {ECO:0000269\|PubMed:28264884, ECO:0000269\|PubMed:31507604}.
Domain:		TSP type-1 domain 0 binds to TSP type-1 domain 4, and TSP type- 1 domain 1 binds to TSP type-1 domain 6 (PubMed:15491616, PubMed:28264884, PubMed:31507604). These interactions mediate multimerization (PubMed:15491616, PubMed:28264884, PubMed:31507604). {ECO:0000269\|PubMed:15491616, ECO:0000269\|PubMed:28264884, ECO:0000269\|PubMed:31507604}.
Disease:		Properdin deficiency (PFD) [MIM:312060]: Results in higher susceptibility to bacterial infections; especially to meningococcal infections. Three phenotypes have been reported: complete deficiency (type I), incomplete deficiency (type II), and dysfunction of properdin (type III). {ECO:0000269\|PubMed:10909851, ECO:0000269\|PubMed:28264884, ECO:0000269\|PubMed:31507604, ECO:0000269\|PubMed:8871668, ECO:0000269\|PubMed:9710744}. Note=The disease is caused by variants affecting the gene represented in this entry.