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Aliases for C4B_2 Gene

Aliases for C4B_2 Gene

  • Complement Component 4B (Chido Blood Group), Copy 2 2 3
  • C3 And PZP-Like Alpha-2-Macroglobulin Domain-Containing Protein 3 4
  • Basic Complement C4 4
  • EC 2.1.1.144 64
  • C4B C4B_2 4
  • EC 2.7.11 64
  • CPAMD3 4
  • CO4 4

External Ids for C4B_2 Gene

Summaries for C4B_2 Gene

Entrez Gene Summary for C4B_2 Gene

  • This gene encodes the basic form of complement factor 4, 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. This GeneID and its associated RefSeq record represent a second copy of C4B found on ALT_REF_LOCI_7. [provided by RefSeq, Jul 2011]

GeneCards Summary for C4B_2 Gene

C4B_2 (Complement Component 4B (Chido Blood Group), Copy 2) is a Protein Coding gene. Diseases associated with C4B_2 include systemic lupus erythematosus and c4b deficiency.

UniProtKB/Swiss-Prot for C4B_2 Gene

  • Non-enzymatic component of the C3 and C5 convertases and thus essential for the propagation of the classical complement pathway. Covalently binds to immunoglobulins and immune complexes and enhances the solubilization of immune aggregates and the clearance of IC through CR1 on erythrocytes. C4A isotype is responsible for effective binding to form amide bonds with immune aggregates or protein antigens, while C4B isotype catalyzes the transacylation of the thioester carbonyl group to form ester bonds with carbohydrate antigens

  • Derived from proteolytic degradation of complement C4, C4a anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes

No data available for Tocris Summary , Gene Wiki entry , PharmGKB "VIP" Summary , fRNAdb sequence ontologies and piRNA Summary for C4B_2 Gene

Genomics for C4B_2 Gene

Genomic Location for C4B_2 Gene

Start:
3,283,246 bp from pter
End:
3,303,870 bp from pter
Size:
20,625 bases
Orientation:
Plus strand

Genomic View for C4B_2 Gene

UCSC Golden Path with GeneCards custom track
Cytogenetic band:
  • 6p21.3 alternate reference locus by HGNC

RefSeq DNA sequence for C4B_2 Gene

No data available for Regulatory Elements for C4B_2 Gene

Proteins for C4B_2 Gene

  • Protein details for C4B_2 Gene (UniProtKB/Swiss-Prot)

    Protein Symbol:
    P0C0L5-CO4B_HUMAN
    Recommended name:
    Complement C4-B
    Protein Accession:
    P0C0L5
    Secondary Accessions:
    • A2BHY4
    • P01028
    • P78445
    • Q13160
    • Q13906
    • Q14033
    • Q14835
    • Q6U2E9
    • Q6U2G1
    • Q6U2I5
    • Q6U2L1
    • Q6U2L7
    • Q6U2L9
    • Q6U2M5
    • Q6VCV8
    • Q96SA7
    • Q9NPK5
    • Q9UIP5

    Protein attributes for C4B_2 Gene

    Size:
    1744 amino acids
    Molecular mass:
    192751 Da
    Quaternary structure:
    • Circulates in blood as a disulfide-linked trimer of alpha, beta and gamma chains
    SequenceCaution:
    • Sequence=AAA99717.1; Type=Erroneous gene model prediction; Evidence={ECO:0000305};

neXtProt entry for C4B_2 Gene

Proteomics data for C4B_2 Gene at MOPED

Selected DME Specific Peptides for C4B_2 Gene

Post-translational modifications for C4B_2 Gene

  • Prior to secretion, the single-chain precursor is enzymatically cleaved to yield non-identical chains alpha, beta and gamma. During activation, the alpha chain is cleaved by C1 into C4a and C4b, and C4b stays linked to the beta and gamma chains. Further degradation of C4b by C1 into the inactive fragments C4c and C4d blocks the generation of C3 convertase. The proteolytic cleavages often are incomplete so that many structural forms can be found in plasma
  • Modification sites at PhosphoSitePlus
  • Glycosylation at Asn226, Asn862, Asn1328, and Asn1391

Other Protein References for C4B_2 Gene

Reactome Protein details:
REFSEQ proteins:

Domains for C4B_2 Gene

UniProtKB/Swiss-Prot:

CO4B_HUMAN
Domain:
  • Contains 1 anaphylatoxin-like domain.:
    • P0C0L5
  • Contains 1 NTR domain.:
    • P0C0L5
genes like me logo Genes that share domains with C4B_2: view

No data available for Gene Families for C4B_2 Gene

Function for C4B_2 Gene

Molecular function for C4B_2 Gene

UniProtKB/Swiss-Prot Function: Non-enzymatic component of the C3 and C5 convertases and thus essential for the propagation of the classical complement pathway. Covalently binds to immunoglobulins and immune complexes and enhances the solubilization of immune aggregates and the clearance of IC through CR1 on erythrocytes. C4A isotype is responsible for effective binding to form amide bonds with immune aggregates or protein antigens, while C4B isotype catalyzes the transacylation of the thioester carbonyl group to form ester bonds with carbohydrate antigens
UniProtKB/Swiss-Prot Function: Derived from proteolytic degradation of complement C4, C4a anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes

Enzyme Numbers (IUBMB) for C4B_2 Gene

No data available for Gene Ontology (GO) - Molecular Function , Phenotypes , Animal Models , miRNA , Transcription Factor Targeting and HOMER Transcription for C4B_2 Gene

Localization for C4B_2 Gene

Subcellular locations from UniProtKB/Swiss-Prot for C4B_2 Gene

Secreted.

No data available for Gene Ontology (GO) - Cellular Components for C4B_2 Gene

Pathways for C4B_2 Gene

SuperPathways for C4B_2 Gene

No Data Available

Interacting Proteins for C4B_2 Gene

Selected Interacting proteins: P0C0L5-CO4B_HUMAN for C4B_2 Gene via I2D

Symbol External ID(s) Details
C2
C4BPA

Gene Ontology (GO) - Biological Process for C4B_2 Gene

None

No data available for Pathways by source for C4B_2 Gene

Transcripts for C4B_2 Gene

mRNA/cDNA for C4B_2 Gene

(1) REFSEQ mRNAs :

Alternative Splicing Database (ASD) splice patterns (SP) for C4B_2 Gene

No ASD Table

Relevant External Links for C4B_2 Gene

GeneLoc Exon Structure for
C4B_2
ECgene alternative splicing isoforms for
C4B_2

Expression for C4B_2 Gene

Integrated Proteomics: protein expression from ProteomicsDB and MOPED for C4B_2 Gene

mRNA Expression by UniProt/SwissProt for C4B_2 Gene

P0C0L5-CO4B_HUMAN
Tissue specificity: Complement component C4 is expressed at highest levels in the liver, at moderate levels in the adrenal cortex, adrenal medulla, thyroid gland,and the kidney, and at lowest levels in the heart, ovary, small intestine, thymus, pancreas and spleen. The extra-hepatic sites of expression may be important for the local protection and inflammatory response.

Orthologs for C4B_2 Gene

No data available for Orthologs and Evolution for C4B_2 Gene

Paralogs for C4B_2 Gene

Selected SIMAP similar genes for C4B_2 Gene using alignment to 1 proteins:

genes like me logo Genes that share paralogs with C4B_2: view

No data available for Paralogs for C4B_2 Gene

Variants for C4B_2 Gene

Polymorphic Variants from UniProtKB/Swiss-Prot for C4B_2 Gene

P0C0L5-CO4B_HUMAN
The complement component C4 is the most polymorphic protein of the complement system. It is the product of 2 closely linked and highly homologous genes, C4A and C4B. Once polymorphic variation is discounted, the 2 isotypes differ by only 4 amino acids at positions 1120-1125: PCPVLD for C4A and LSPVIH for C4B. The 2 isotypes bear several antigenic determinants defining Chido/Rodgers blood group system [MIM:614374]. Rodgers determinants are generally associated with C4A allotypes, and Chido with C4B. Variations at these loci involve not only nucleotide polymorphisms, but also gene number and gene size. The second copy of C4B gene present in some individuals has been called C4B_2 by the HUGO Gene Nomenclature Committee (HGNC). Some individuals may lack either C4A, or C4B gene. Partial deficiency of C4A or C4B is the most commonly inherited immune deficiency known in humans with a combined frequency over 31% in the normal Caucasian population (PubMed:11367523).

Relevant External Links for C4B_2 Gene

HapMap Linkage Disequilibrium report
C4B_2

No data available for Sequence variations from dbSNP and Humsavar and Structural Variations from Database of Genomic Variants (DGV) for C4B_2 Gene

Disorders for C4B_2 Gene

UniProtKB/Swiss-Prot

CO4B_HUMAN
  • Systemic lupus erythematosus (SLE) [MIM:152700]: A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow. {ECO:0000269 PubMed:10092831, ECO:0000269 PubMed:17503323}. Note=Disease susceptibility is associated with variations affecting the gene represented in this entry. Interindividual copy-number variation (CNV) of complement component C4 and associated polymorphisms result in different susceptibilities to SLE. The risk of SLE susceptibility has been shown to be significantly increased among subjects with only two copies of total C4. A high copy number is a protective factor against SLE.
  • Complement component 4B deficiency (C4BD) [MIM:614379]: A rare defect of the complement classical pathway associated with the development of autoimmune disorders, mainly systemic lupus with or without associated glomerulonephritis. {ECO:0000269 PubMed:3265961}. Note=The disease is caused by mutations affecting the gene represented in this entry.
genes like me logo Genes that share disorders with C4B_2: view

Publications for C4B_2 Gene

  1. Linkage analysis of the C4A/C4B copy number variation and polymorphisms of the adjacent steroid 21-hydroxylase gene in a healthy population. (PMID: 19505723) Blasko B. … Szilagyi A. (Mol. Immunol. 2009) 2 3
  2. The structural basis of the multiple forms of human complement component C4. (PMID: 6546707) Belt K.T. … Porter R.R. (Cell 1984) 3 4
  3. Structural basis of the polymorphism of human complement components C4A and C4B: gene size, reactivity and antigenicity. (PMID: 2431902) Yu C.Y. … Porter R.R. (EMBO J. 1986) 3 4
  4. Gene copy-number variation and associated polymorphisms of complement component C4 in human systemic lupus erythematosus (SLE): low copy number is a risk factor for and high copy number is a protective factor against SLE susceptibility in European Americans. (PMID: 17503323) Yang Y. … Yu C.Y. (Am. J. Hum. Genet. 2007) 3 4
  5. Low complement C4B gene copy number predicts short-term mortality after acute myocardial infarction. (PMID: 18032375) BlaskA^ B. … Arason G.J. (Int. Immunol. 2008) 3

Products for C4B_2 Gene

  • QIAGEN qRT-PCR Assays for microRNAs that regulate C4B_2
    • QuantiTect SYBR Green Assays in human,mouse,rat
    • Pre-validated RT² qPCR Primer Assay in human,mouse,rat
    • QuantiFast Probe-based Assays in human,mouse,rat
    • Predesigned siRNA for gene silencing in human,mouse,rat for C4B_2
    • Block miRNA regulation of C4B_2 using miScript Target Protectors

    Sources for C4B_2 Gene

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