6qsw

Structural highlights

Disease

CFAB_HUMAN Defects in CFB are a cause of susceptibility to hemolytic uremic syndrome atypical type 4 (AHUS4) [MIM:612924. An atypical form of hemolytic uremic syndrome. It is a complex genetic disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal failure and absence of episodes of enterocolitis and diarrhea. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease. Note=Susceptibility to the development of atypical hemolytic uremic syndrome can be conferred by mutations in various components of or regulatory factors in the complement cascade system. Other genes may play a role in modifying the phenotype.^{[1] [2]}

Function

CFAB_HUMAN Factor B which is part of the alternate pathway of the complement system is cleaved by factor D into 2 fragments: Ba and Bb. Bb, a serine protease, then combines with complement factor 3b to generate the C3 or C5 convertase. It has also been implicated in proliferation and differentiation of preactivated B-lymphocytes, rapid spreading of peripheral blood monocytes, stimulation of lymphocyte blastogenesis and lysis of erythrocytes. Ba inhibits the proliferation of preactivated B-lymphocytes.

References

1. ↑ Goicoechea de Jorge E, Harris CL, Esparza-Gordillo J, Carreras L, Arranz EA, Garrido CA, Lopez-Trascasa M, Sanchez-Corral P, Morgan BP, Rodriguez de Cordoba S. Gain-of-function mutations in complement factor B are associated with atypical hemolytic uremic syndrome. Proc Natl Acad Sci U S A. 2007 Jan 2;104(1):240-5. Epub 2006 Dec 20. PMID:17182750 doi:10.1073/pnas.0603420103
2. ↑ Maga TK, Nishimura CJ, Weaver AE, Frees KL, Smith RJ. Mutations in alternative pathway complement proteins in American patients with atypical hemolytic uremic syndrome. Hum Mutat. 2010 Jun;31(6):E1445-60. doi: 10.1002/humu.21256. PMID:20513133 doi:10.1002/humu.21256
3. ↑ Schubart A, Anderson K, Mainolfi N, Sellner H, Ehara T, Adams CM, Mac Sweeney A, Liao SM, Crowley M, Littlewood-Evans A, Sarret S, Wieczorek G, Perrot L, Dubost V, Flandre T, Zhang Y, Smith RJH, Risitano AM, Karki RG, Zhang C, Valeur E, Sirockin F, Gerhartz B, Erbel P, Hughes N, Smith TM, Cumin F, Argikar UA, Haraldsson B, Mogi M, Sedrani R, Wiesmann C, Jaffee B, Maibaum J, Flohr S, Harrison R, Eder J. Small-molecule factor B inhibitor for the treatment of complement-mediated diseases. Proc Natl Acad Sci U S A. 2019 Mar 29. pii: 1820892116. doi:, 10.1073/pnas.1820892116. PMID:30926668 doi:http://dx.doi.org/10.1073/pnas.1820892116