Seroatlas · Human Serome Atlas

C8B

Complement component C8 beta chain

Also known as: CO8B_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P07358
Gene
C8B
Ensembl
ENSG00000021852
Chromosome
1
Canonical length
591 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Predicted secreted proteins
Secretome location
Secreted to blood

OverviewNCBI Gene

This gene encodes one of the three subunits of the complement component 8 (C8) protein. C8 is composed of equimolar amounts of alpha, beta and gamma subunits, which are encoded by three separate genes. C8 is one component of the membrane attack complex, which mediates cell lysis, and it initiates membrane penetration of the complex. This protein mediates the interaction of C8 with the C5b-7 membrane attack complex precursor. In humans deficiency of this protein is associated with increased risk of meningococcal infections. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2013]

Canonical amino-acid sequenceUniProt

591 residues, UniProt reviewed canonical sequence.

>P07358|C8B
     1  MKNSRTWAWR APVELFLLCA ALGCLSLPGS RGERPHSFGS NAVNKSFAKS RQMRSVDVTL
    61  MPIDCELSSW SSWTTCDPCQ KKRYRYAYLL QPSQFHGEPC NFSDKEVEDC VTNRPCGSQV
   121  RCEGFVCAQT GRCVNRRLLC NGDNDCGDQS DEANCRRIYK KCQHEMDQYW GIGSLASGIN
   181  LFTNSFEGPV LDHRYYAGGC SPHYILNTRF RKPYNVESYT PQTQGKYEFI LKEYESYSDF
   241  ERNVTEKMAS KSGFSFGFKI PGIFELGISS QSDRGKHYIR RTKRFSHTKS VFLHARSDLE
   301  VAHYKLKPRS LMLHYEFLQR VKRLPLEYSY GEYRDLFRDF GTHYITEAVL GGIYEYTLVM
   361  NKEAMERGDY TLNNVHACAK NDFKIGGAIE EVYVSLGVSV GKCRGILNEI KDRNKRDTMV
   421  EDLVVLVRGG ASEHITTLAY QELPTADLMQ EWGDAVQYNP AIIKVKVEPL YELVTATDFA
   481  YSSTVRQNMK QALEEFQKEV SSCHCAPCQG NGVPVLKGSR CDCICPVGSQ GLACEVSYRK
   541  NTPIDGKWNC WSNWSSCSGR RKTRQRQCNN PPPQNGGSPC SGPASETLDC S

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C8B 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
Cell surface
Secreted
No
Transmembrane segments
4
Mean surface accessibility (rSASA)
0.32
Highest tissue expression
608 nTPM

Expression across tissuesHPA

Tissue

  • liver: 608 nTPM
  • lung: 4.8 nTPM
  • gallbladder: 0.3 nTPM
  • testis: 0.3 nTPM
  • salivary gland: 0.2 nTPM
  • spleen: 0.2 nTPM

Single-cell type

  • hepatocytes: 351 nCPM
  • cholangiocytes: 20 nCPM
  • late spermatids: 18 nCPM
  • early spermatids: 9.6 nCPM
  • respiratory ciliated cells: 5.4 nCPM
  • endometrial ciliated cells: 2.6 nCPM

Immune cell

  • basophil: 2.3 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • amygdala: 0 nTPM
  • basal ganglia: 0 nTPM
  • cerebellum: 0 nTPM
  • cerebral cortex: 0 nTPM
  • choroid plexus: 0 nTPM
  • hippocampal formation: 0 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about C8B.

Disease | AllUniProt

Conditions C8B is implicated in, by any mechanism.

  • Complement component 8 deficiency, 2 (C8D2) MIM:613789

Disease | GeneticClinVar

42 pathogenic / likely-pathogenic of 443 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Disease | ImmuneIEDB

Conditions an epitope on C8B was assayed in.

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)
1.33
gnomAD pLI
0
gnomAD missense Z
-0.74
DepMap mean gene effect
0.05
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 2% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C8B as an antibody target. Whether an autoantibody or antibody against C8B could matter depends on whether native C8B is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C8B is annotated at the cell surface, where native C8B is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label C8B as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C8B. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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