ImmunoDeficiency Resource (IDR)

Names

HUGO name: C4A

Alias(es):

Localization

Reference sequences

Chromosomal location

Maps

Variations / Mutations

Other gene-based resources

Description

Protein function:

C4 plays a central role in the activation of the classical pathway of the complement system. It is processed by activated C1 which remove from the alpha chain the C4a anaphylatoxin.

Subunit:

This protein is synthesized as a single-chain precursor and, prior to secretion, is enzymatically cleaved to form a trimer of nonidentical chains (alpha, beta, and gamma).

Miscellaneous:

C4a allotypes react more rapidly with the amino group of peptide antigens while C4b allotypes react more rapidly with the hydroxyl group of carbohydrate antigens.

Polymorphism:

Human complement component C4 is polymorphic with at least two loci, C4a and C4b. 13 alleles of C4a and 22 alleles of C4b have been detected.

Structures (PDB)

Domains

Anaphylatoxin-like domain: 702-736

Other features

Signal peptide: 1-19

Complement C4, beta chain: 20-675

Propeptide: 676-679

Complement C4, alpha chain: 680-1446

Propeptide: 1447-1453

Complement C4, gamma chain: 1454-1744

Released active peptide C4a anaphylatoxin: 680-756

Disulfide bond: 702-728

Disulfide bond: 703-735

Disulfide bond: 716-736

Other related resourses:

Expression pattern for human

Animal models

Mouse

Fly

C. elegans