|Protein Name||Complement factor H|
|Ref Sequence ID||NP_001029108.1|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Presence in other biological fluids/tissue/cells||retinal pigment epithelial cells,endothelial cells, epithelial cells, platelets, mesenchymal stem cells, liver|
|Protein Function||Serum glycoprotein; accelerates the decay of the alternative pathway C3 convertase; cofactor for factor I-mediated cleavage and inactivation of C3b; recognize specific markers on host cells and control complement on self surfaces; detects and binds to initial C3b deposits in combination with specific markers on host cells;|
|Biochemical Properties||actual conformation of factor H may be affected by the ionic strength and pH of its local microenvironment;|
|Significance in milk||immune protection against environmental pathogens|
|PTMs||Glycosylation; as found in humans, eight N-glycans; forty disulfide bonds; absence of hybrid and oligomannose structures; presence of complex, diantennary disialylated, non-fucosylated glycans; Disialylated fucosylated and monosialylated non-fucosylated oligosaccharides were also identified; Asn511, Asn700, Asn784, Asn804, Asn864, Asn893, Asn1011 and Asn1077 are glycosylated essentially by diantennary disialylated structures with a relative; absence of hybrid and oligomannose structures|
| Site(s) of PTM(s) |
|Predicted Disorder Regions||NA|
|TM Helix Prediction||No TM helices|
|Additional Comments||In the absence of factor H, spontaneous activation of the alternative pathway of complement occurs in plasma, which leads to consumption of complement components C3 and factor B|
|Bibliography||1. Fenaille, F., Le Mignon, M., Groseil, C., Ramon, C., Riandé, S., Siret, L., & Bihoreau, N. (2007). Site-specific N-glycan characterization of human complement factor H. Glycobiology, 17(9), 932–944. https://doi.org/10.1093/glycob/cwm060. |
2. Okemefuna, A. I., Li, K., Nan, R., Ormsby, R. J., Sadlon, T., Gordon, D. L., & Perkins, S. J. (2009). Multimeric Interactions between Complement Factor H and Its C3d Ligand Provide New Insight on Complement Regulation. Journal of Molecular Biology, 391(1), 119–135. https://doi.org/10.1016/j.jmb.2009.06.013.
3. Harrison, R. A., & Lachmann, P. J. (1980). The physiological breakdown of the third component of human complement. Molecular Immunology, 17(1), 9–20. https://doi.org/10.1016/0161-5890(80)90119-4.
4. Licht, C., Pluthero, F. G., Li, L., Christensen, H., Habbig, S., Hoppe, B., … Kahr, W. H. A. (2009). Platelet-associated complement factor H in healthy persons and patients with atypical HUS. Blood, 114(20), 4538–4545. https://doi.org/10.1182/blood-2009-03-205096.
5. Chen, M., Forrester, J. V, & Xu, H. (2007). Synthesis of complement factor H by retinal pigment epithelial cells is down-regulated by oxidized photoreceptor outer segments. Experimental Eye Research, 84(4), 635–645. https://doi.org/10.1016/j.exer.2006.11.015.
6. Brooimans, R. A., van der Ark, A. A., Buurman, W. A., van Es, L. A., & Daha, M. R. (1990). Differential regulation of complement factor H and C3 production in human umbilical vein endothelial cells by IFN-gamma and IL-1. Journal of Immunology (Baltimore, Md. : 1950), 144(10), 3835–3840. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/2139673.
7. Adinolfi, M., Dobson, N. C., & Bradwell, A. R. (1981). Synthesis of two components of human complement, beta 1H and C3bINA, during fetal life. Acta Paediatrica Scandinavica, 70(5), 705–710. https://doi.org/10.1111/j.1651-2227.1981.tb05772.