Seroatlas · Human Serome Atlas

C8A

Complement component C8 alpha chain

Also known as: CO8A_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P07357
Gene
C8A
Ensembl
ENSG00000157131
Chromosome
1
Canonical length
584 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Potential drug targets, Predicted secreted proteins, Transporters
Subcellular location
Plasma membrane
Secretome location
Secreted to blood

OverviewNCBI Gene

C8 is a component of the complement system and contains three polypeptides, alpha, beta and gamma. This gene encodes the alpha subunit of C8. C8 participates in the formation of the membrane attack complex (MAC). The MAC assembles on bacterial membranes to form a pore, permitting disruption of bacterial membrane organization. Mutations in this gene cause complement C8 alpha-gamma deficiency. [provided by RefSeq, Nov 2008]

Canonical amino-acid sequenceUniProt

584 residues, UniProt reviewed canonical sequence.

>P07357|C8A
     1  MFAVVFFILS LMTCQPGVTA QEKVNQRVRR AATPAAVTCQ LSNWSEWTDC FPCQDKKYRH
    61  RSLLQPNKFG GTICSGDIWD QASCSSSTTC VRQAQCGQDF QCKETGRCLK RHLVCNGDQD
   121  CLDGSDEDDC EDVRAIDEDC SQYEPIPGSQ KAALGYNILT QEDAQSVYDA SYYGGQCETV
   181  YNGEWRELRY DSTCERLYYG DDEKYFRKPY NFLKYHFEAL ADTGISSEFY DNANDLLSKV
   241  KKDKSDSFGV TIGIGPAGSP LLVGVGVSHS QDTSFLNELN KYNEKKFIFT RIFTKVQTAH
   301  FKMRKDDIML DEGMLQSLME LPDQYNYGMY AKFINDYGTH YITSGSMGGI YEYILVIDKA
   361  KMESLGITSR DITTCFGGSL GIQYEDKINV GGGLSGDHCK KFGGGKTERA RKAMAVEDII
   421  SRVRGGSSGW SGGLAQNRST ITYRSWGRSL KYNPVVIDFE MQPIHEVLRH TSLGPLEAKR
   481  QNLRRALDQY LMEFNACRCG PCFNNGVPIL EGTSCRCQCR LGSLGAACEQ TQTEGAKADG
   541  SWSCWSSWSV CRAGIQERRR ECDNPAPQNG GASCPGRKVQ TQAC

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C8A 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)
0.31
Highest tissue expression
464 nTPM

Expression across tissuesHPA

Tissue

  • liver: 464 nTPM
  • gallbladder: 1.6 nTPM
  • duodenum: 0.6 nTPM
  • small intestine: 0.4 nTPM
  • kidney: 0.1 nTPM
  • pancreas: 0.1 nTPM

Single-cell type

  • hepatocytes: 385 nCPM
  • tuft cells: 12 nCPM
  • cholangiocytes: 7.2 nCPM
  • hepatic stellate cells: 6.5 nCPM
  • kupffer cells: 6.1 nCPM
  • epicardial cells: 2.3 nCPM

Immune cell

  • basophil: 0 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 C8A.

Disease | AllUniProt

Conditions C8A is implicated in, by any mechanism.

  • Complement component 8 deficiency, 1 (C8D1) MIM:613790

Disease | GeneticClinVar

27 pathogenic / likely-pathogenic of 449 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Disease | ImmuneIEDB

Conditions an epitope on C8A 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)
1.18
gnomAD pLI
0
gnomAD missense Z
-1.07
DepMap mean gene effect
0.08
DepMap dependency class
none

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 C8A as an antibody target. Whether an autoantibody or antibody against C8A could matter depends on whether native C8A is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C8A is annotated at the cell surface, where native C8A 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 C8A as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C8A. 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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