FunctionA positive regulator of the alternate pathway of complement. It binds to and stabilizes the C3- and C5-convertase enzyme complexes.
Involvement in diseaseDefects in CFP are the cause of properdin deficiency (PFD) [MIM:312060]. PFD 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).