ID:C4BPA_HUMAN DESCRIPTION: RecName: Full=C4b-binding protein alpha chain; Short=C4bp; AltName: Full=Proline-rich protein; Short=PRP; Flags: Precursor; FUNCTION: Controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. Alpha chain binds C4b. It interacts also with anticoagulant protein S and with serum amyloid P component. SUBUNIT: Disulfide-linked complex of alpha and beta chains of 3 possible sorts: a 570 kDa complex of 7 alpha chains and 1 beta chain, a 530 kDa homoheptamer of alpha chains or a 500 kDa complex of 6 alpha chains and 1 beta chain. The central body of the alpha chain homopolymer supports tentacles, each with the binding site for C4b at the end. INTERACTION: P13050:arp4 (xeno); NbExp=5; IntAct=EBI-978348, EBI-978341; SUBCELLULAR LOCATION: Secreted. TISSUE SPECIFICITY: Chylomicrons in the plasma. SIMILARITY: Contains 8 Sushi (CCP/SCR) domains. CAUTION: It is uncertain whether Met-1 or Met-17 is the initiator.
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on P04003
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
Biological Process: GO:0002376 immune system process GO:0006958 complement activation, classical pathway GO:0030449 regulation of complement activation GO:0045087 innate immune response GO:0045732 positive regulation of protein catabolic process GO:0045959 negative regulation of complement activation, classical pathway GO:1903027 regulation of opsonization
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Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
