Harmonizome 3.0

complement component 4B (Chido blood group)

This gene encodes the basic form of complement factor 4, and together with the C4A gene, is part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion. The trimer provides a surface for interaction between the antigen-antibody complex and other complement components. The alpha chain may be cleaved to release C4 anaphylatoxin, a mediator of local inflammation. Deficiency of this protein is associated with systemic lupus erythematosus. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. Varying haplotypes of this gene cluster exist, such that individuals may have 1, 2, or 3 copies of this gene. In addition, this gene exists as a long form and a short form due to the presence or absence of a 6.4 kb endogenous HERV-K retrovirus in intron 9. [provided by RefSeq, May 2020]

From GeneRIF Biological Term Annotations

genes co-occuring with the biological term c4b in literature-supported statements describing functions of genes from the GeneRIF Biological Term Annotations dataset.

From Pathway Commons Protein-Protein Interactions

interacting proteins for C4B from the Pathway Commons Protein-Protein Interactions dataset.

From LINCS L1000 CMAP CRISPR Knockout Consensus Signatures

genes differentially expressed following the C4B gene perturbation from the LINCS L1000 CMAP CRISPR Knockout Consensus Signatures dataset.

From dbGAP Gene-Trait Associations

genes associated with the trait Complement C4b-Binding Protein in GWAS and other genetic association datasets from the dbGAP Gene-Trait Associations dataset.

From GAD Gene-Disease Associations

genes associated with the disease plasma c4b binding protein levels in GWAS and other genetic association datasets from the GAD Gene-Disease Associations dataset.

From GAD Gene-Disease Associations

genes associated with the disease complement c4b-binding protein in GWAS and other genetic association datasets from the GAD Gene-Disease Associations dataset.

From GO Molecular Function Annotations 2015

genes performing the complement component c4b binding molecular function from the curated GO Molecular Function Annotations 2015 dataset.

From GO Molecular Function Annotations 2015

genes performing the complement component c4b receptor activity molecular function from the curated GO Molecular Function Annotations 2015 dataset.

From GWAS Catalog SNP-Phenotype Associations

genes associated with the C4b binding protein levels phenotype in GWAS datasets from the GWAS Catalog SNP-Phenotype Associations dataset.

From OMIM Gene-Disease Associations

genes associated with the c4b deficiency phenotype from the curated OMIM Gene-Disease Associations dataset.

From DisGeNET Gene-Disease Associations

genes associated with the disease Decreased Serum Complement C4B in GWAS and other genetic association datasets from the DisGeNET Gene-Disease Associations dataset.

From GO Molecular Function Annotations 2023

genes performing the complement component C4b binding molecular function from the curated GO Molecular Function Annotations 2023 dataset.

From GO Molecular Function Annotations 2023

genes performing the complement component C4b receptor activity molecular function from the curated GO Molecular Function Annotations 2023 dataset.

From GO Molecular Function Annotations 2025

genes performing the complement component C4b binding molecular function from the curated GO Molecular Function Annotations 2025 dataset.

From GO Molecular Function Annotations 2025

genes performing the complement component C4b receptor activity molecular function from the curated GO Molecular Function Annotations 2025 dataset.

From GWAS Catalog SNP-Phenotype Associations 2025

genes associated with the C4b binding protein levels phenotype in GWAS datasets from the GWAS Catalog SNP-Phenotype Associations 2025 dataset.