Properdin and Factor H: Opposing players on the alternative complement pathway see-saw
Properdin and factor H are two key regulatory proteins having opposite functions in the alternative complement pathway. Properdin up-regulates the alternative pathway by stabilising the C3bBb complex, whereas factor H down-regulates the pathway by promoting proteolytic degradation of C3b. While fact...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-04-01
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| Series: | Frontiers in Immunology |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00093/full |
| _version_ | 1818591811244916736 |
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| author | Lubna eKouser Munirah eAbdul-Aziz Munirah eAbdul-Aziz Annapurna eNayak Cordula M Stover Robert B Sim Robert B Sim Uday eKishore |
| author_facet | Lubna eKouser Munirah eAbdul-Aziz Munirah eAbdul-Aziz Annapurna eNayak Cordula M Stover Robert B Sim Robert B Sim Uday eKishore |
| author_sort | Lubna eKouser |
| collection | DOAJ |
| description | Properdin and factor H are two key regulatory proteins having opposite functions in the alternative complement pathway. Properdin up-regulates the alternative pathway by stabilising the C3bBb complex, whereas factor H down-regulates the pathway by promoting proteolytic degradation of C3b. While factor H is mainly produced in the liver, there are several extrahepatic sources. In addition to the liver, factor H is also synthesized in fetal tubuli, keratinocytes, skin fibroblasts, ocular tissue, adipose tissue, brain, lungs, heart, spleen, pancreas, kidney, muscle, and placenta. Neutrophils are the major source of properdin, and it is also produced by monocytes, T cells and bone marrow progenitor cell line. Properdin is released by neutrophils from intracellular stores following stimulation by N-formyl-methionine-leucine-phenylalanine and tumour necrosis factor alpha. The HEP G2 cells derived from human liver has been found to produce functional properdin. Endothelial cells also produce properdin when induced by shear stress, thus is a physiological source for plasma properdin.. The diverse range of extrahepatic sites for synthesis of these two complement regulators suggests the importance and need for local availability of the proteins. Here, we discuss the significance of the local synthesis of properdin and factor H. This assumes greater importance in view of recently identified unexpected and novel roles of properdin and factor H that are potentially independent of their involvement in the complement regulation. |
| first_indexed | 2024-12-16T10:18:22Z |
| format | Article |
| id | doaj.art-631e8e6522ca4408bb29543f3aa62e4d |
| institution | Directory Open Access Journal |
| issn | 1664-3224 |
| language | English |
| last_indexed | 2024-12-16T10:18:22Z |
| publishDate | 2013-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Immunology |
| spelling | doaj.art-631e8e6522ca4408bb29543f3aa62e4d2022-12-21T22:35:23ZengFrontiers Media S.A.Frontiers in Immunology1664-32242013-04-01410.3389/fimmu.2013.0009347548Properdin and Factor H: Opposing players on the alternative complement pathway see-sawLubna eKouser0Munirah eAbdul-Aziz1Munirah eAbdul-Aziz2Annapurna eNayak3Cordula M Stover4Robert B Sim5Robert B Sim6Uday eKishore7Brunel UniversityBrunel UniversityOxford UniversityBrunel UniversityUniversity of LeicesterOxford UniversityKingston University LondonBrunel UniversityProperdin and factor H are two key regulatory proteins having opposite functions in the alternative complement pathway. Properdin up-regulates the alternative pathway by stabilising the C3bBb complex, whereas factor H down-regulates the pathway by promoting proteolytic degradation of C3b. While factor H is mainly produced in the liver, there are several extrahepatic sources. In addition to the liver, factor H is also synthesized in fetal tubuli, keratinocytes, skin fibroblasts, ocular tissue, adipose tissue, brain, lungs, heart, spleen, pancreas, kidney, muscle, and placenta. Neutrophils are the major source of properdin, and it is also produced by monocytes, T cells and bone marrow progenitor cell line. Properdin is released by neutrophils from intracellular stores following stimulation by N-formyl-methionine-leucine-phenylalanine and tumour necrosis factor alpha. The HEP G2 cells derived from human liver has been found to produce functional properdin. Endothelial cells also produce properdin when induced by shear stress, thus is a physiological source for plasma properdin.. The diverse range of extrahepatic sites for synthesis of these two complement regulators suggests the importance and need for local availability of the proteins. Here, we discuss the significance of the local synthesis of properdin and factor H. This assumes greater importance in view of recently identified unexpected and novel roles of properdin and factor H that are potentially independent of their involvement in the complement regulation.http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00093/fullProperdinbiosynthesiscomplementfactor Hextrahepatic |
| spellingShingle | Lubna eKouser Munirah eAbdul-Aziz Munirah eAbdul-Aziz Annapurna eNayak Cordula M Stover Robert B Sim Robert B Sim Uday eKishore Properdin and Factor H: Opposing players on the alternative complement pathway see-saw Frontiers in Immunology Properdin biosynthesis complement factor H extrahepatic |
| title | Properdin and Factor H: Opposing players on the alternative complement pathway see-saw |
| title_full | Properdin and Factor H: Opposing players on the alternative complement pathway see-saw |
| title_fullStr | Properdin and Factor H: Opposing players on the alternative complement pathway see-saw |
| title_full_unstemmed | Properdin and Factor H: Opposing players on the alternative complement pathway see-saw |
| title_short | Properdin and Factor H: Opposing players on the alternative complement pathway see-saw |
| title_sort | properdin and factor h opposing players on the alternative complement pathway see saw |
| topic | Properdin biosynthesis complement factor H extrahepatic |
| url | http://journal.frontiersin.org/Journal/10.3389/fimmu.2013.00093/full |
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