Seroatlas · Human Serome Atlas

C4BPB

C4b-binding protein beta chain

Also known as: C4BP, C4BPB_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: P20851
Gene: C4BPB
Ensembl: ENSG00000123843
Chromosome: 1
Canonical length: 252 aa
Protein class: Human disease related genes, Plasma proteins, Predicted secreted proteins
Subcellular location: Golgi apparatus
Secretome location: Secreted to blood
Quaternary structure: Homoheptamer

OverviewNCBI Gene

This gene encodes a member of a superfamily of proteins composed predominantly of tandemly arrayed short consensus repeats of approximately 60 amino acids. A single, unique beta-chain encoded by this gene assembles with seven identical alpha-chains into the predominant isoform of C4b-binding protein, a multimeric protein that controls activation of the complement cascade through the classical pathway. C4b-binding protein has a regulatory role in the coagulation system also, mediated through the beta-chain binding of protein S, a vitamin K-dependent protein that serves as a cofactor of activated protein C. The genes encoding both alpha and beta chains are located adjacent to each other on human chromosome 1 in the regulator of complement activation gene cluster. Alternative splicing gives rise to multiple transcript variants. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

252 residues, UniProt reviewed canonical sequence.

>P20851|C4BPB
     1  MFFWCACCLM VAWRVSASDA EHCPELPPVD NSIFVAKEVE GQILGTYVCI KGYHLVGKKT
    61  LFCNASKEWD NTTTECRLGH CPDPVLVNGE FSSSGPVNVS DKITFMCNDH YILKGSNRSQ
   121  CLEDHTWAPP FPICKSRDCD PPGNPVHGYF EGNNFTLGST ISYYCEDRYY LVGVQEQQCV
   181  DGEWSSALPV CKLIQEAPKP ECEKALLAFQ ESKNLCEAME NFMQQLKESG MTMEELKYSL
   241  ELKKAELKAK LL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C4BPB can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.41
Highest tissue expression: 440 nTPM

Expression across tissuesHPA

Tissue

liver: 440 nTPM
ovary: 34 nTPM
pancreas: 9.1 nTPM
stomach: 8.2 nTPM
placenta: 5.8 nTPM
small intestine: 4.2 nTPM

Single-cell type

hepatocytes: 686 nCPM
cholangiocytes: 72 nCPM
breast lactating cells: 56 nCPM
gastric progenitor cells: 50 nCPM
parietal cells: 41 nCPM
ovarian stromal cells: 40 nCPM

Immune cell

plasmacytoid DC: 1.1 nTPM
naive CD4 T-cell: 0.7 nTPM
naive CD8 T-cell: 0.2 nTPM
basophil: 0 nTPM
classical monocyte: 0 nTPM
eosinophil: 0 nTPM

Brain region

white matter: 0.5 nTPM
cerebral cortex: 0.4 nTPM
pons: 0.4 nTPM
amygdala: 0.3 nTPM
basal ganglia: 0.3 nTPM
hypothalamus: 0.3 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about C4BPB.

Disease | ImmuneIEDB

Conditions an epitope on C4BPB was assayed in.

rheumatoid arthritis B cell

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1.3
gnomAD pLI: 0
gnomAD missense Z: 0.46
DepMap mean gene effect: -0.06
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C4BPB as an antibody target. Whether an autoantibody or antibody against C4BPB could matter depends on whether native C4BPB is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C4BPB is annotated as secreted, so native C4BPB circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label C4BPB as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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