Seroatlas · Human Serome Atlas

CD55

Complement decay-accelerating factor

Also known as: CR, CROM, DAF, DAF_HUMAN, TC

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

Protein identityUniProt · HPA

UniProt accession
P08174
Gene
CD55
Ensembl
ENSG00000196352
Chromosome
1
Canonical length
381 aa
Protein class
Blood group antigen proteins, CD markers, Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins, Predicted membrane proteins, Predicted secreted proteins
Secretome location
Secreted to blood
Quaternary structure
Homodimer

OverviewNCBI Gene

This gene encodes a glycoprotein involved in the regulation of the complement cascade. Binding of the encoded protein to complement proteins accelerates their decay, thereby disrupting the cascade and preventing damage to host cells. Antigens present on this protein constitute the Cromer blood group system (CROM). Alternative splicing results in multiple transcript variants. The predominant transcript variant encodes a membrane-bound protein, but alternatively spliced transcripts may produce soluble proteins. [provided by RefSeq, Jul 2014]

Canonical amino-acid sequenceUniProt

381 residues, UniProt reviewed canonical sequence.

>P08174|CD55
     1  MTVARPSVPA ALPLLGELPR LLLLVLLCLP AVWGDCGLPP DVPNAQPALE GRTSFPEDTV
    61  ITYKCEESFV KIPGEKDSVI CLKGSQWSDI EEFCNRSCEV PTRLNSASLK QPYITQNYFP
   121  VGTVVEYECR PGYRREPSLS PKLTCLQNLK WSTAVEFCKK KSCPNPGEIR NGQIDVPGGI
   181  LFGATISFSC NTGYKLFGST SSFCLISGSS VQWSDPLPEC REIYCPAPPQ IDNGIIQGER
   241  DHYGYRQSVT YACNKGFTMI GEHSIYCTVN NDEGEWSGPP PECRGKSLTS KVPPTVQKPT
   301  TVNVPTTEVS PTSQKTTTKT TTPNAQATRS TPVSRTTKHF HETTPNKGSG TTSGTTRLLS
   361  GHTCFTLTGL LGTLVTMGLL T

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CD55 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
0
Mean surface accessibility (rSASA)
0.47
Highest tissue expression
211 nTPM

Expression across tissuesHPA

Tissue

  • lung: 211 nTPM
  • urinary bladder: 169 nTPM
  • adrenal gland: 151 nTPM
  • salivary gland: 115 nTPM
  • skeletal muscle: 113 nTPM
  • blood vessel: 104 nTPM

Single-cell type

  • neutrophils: 7,705 nCPM
  • alveolar cells type 1: 2,488 nCPM
  • ocular epithelial cells: 1,980 nCPM
  • epicardial cells: 1,904 nCPM
  • esophageal apical cells: 1,430 nCPM
  • neutrophil progenitors: 1,332 nCPM

Immune cell

  • neutrophil: 653 nTPM
  • basophil: 321 nTPM
  • eosinophil: 249 nTPM
  • non-classical monocyte: 225 nTPM
  • classical monocyte: 175 nTPM
  • intermediate monocyte: 174 nTPM

Brain region

  • white matter: 57 nTPM
  • hypothalamus: 51 nTPM
  • cerebral cortex: 44 nTPM
  • pons: 43 nTPM
  • basal ganglia: 38 nTPM
  • thalamus: 37 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CD55.

Disease | AllUniProt

Conditions CD55 is implicated in, by any mechanism.

  • Complement hyperactivation, angiopathic thrombosis, and protein-losing enteropathy (CHAPLE) MIM:226300

Disease | GeneticClinVar

28 pathogenic / likely-pathogenic of 292 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • Complement hyperactivation-angiopathic thrombosis-protein-losing enteropathy syndrome
  • CD55-related disorder
  • Cromer blood group system
  • CROMER BLOOD GROUP SYSTEM, Dr(a-) PHENOTYPE

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)
1.27
gnomAD pLI
0
gnomAD missense Z
0.92
DepMap mean gene effect
-0.07
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

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CD55 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CD55 as an antibody target. Whether an autoantibody or antibody against CD55 could matter depends on whether native CD55 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CD55 is annotated at the cell surface, where native CD55 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 CD55 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CD55. 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).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...