Complement component 4
| complement component 4A (Rodgers blood group) | |
|---|---|
| Identifiers | |
| Symbol | C4A |
| Entrez | 720 |
| HUGO | 1323 |
| OMIM | 120810 |
| RefSeq | NM_007293 |
| UniProt | P0C0L4 |
| Other data | |
| Locus | Chr. 6 p21.3 |
| complement component 4B (Chido blood group) | |
|---|---|
| Identifiers | |
| Symbol | C4B |
| Entrez | 721 |
| HUGO | 1324 |
| OMIM | 120820 |
| RefSeq | NM_000592 |
| UniProt | P0C0L5 |
| Other data | |
| Locus | Chr. 6 p21.3 |
Complement component 4 is a protein involved in the complement system.
It is cleaved into proteins 4a and 4b; 4b can be further cleaved into 4c and 4d.[1]
- C4a is an anaphylatoxin.
- C4b forms part of C3-convertase, in conjunction with 2a:
- C4b can bind CR1.
Classical pathway. (Some labels are in Polish.)
Clinical significance
It is responsible for the Chido Rodgers blood group system.[2]
C4d has been identified as a biomarker for systemic lupus erythematosus.[3]
References
- ↑ http://www.immunologyreport.com/ATC2013/pdf/MacConmara.pdf
- ↑ Chido Rodgers blood group system at BGMUT Blood Group Antigen Gene Mutation Database at NCBI, NIH
- ↑ Liu CC, Manzi S, Kao AH, Navratil JS, Ruffing MJ, Ahearn JM (2005). "Reticulocytes bearing C4d as biomarkers of disease activity for systemic lupus erythematosus". Arthritis Rheum. 52 (10): 3087–99. doi:10.1002/art.21305. PMID 16200588.
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