Seroatlas · Human Serome Atlas

C3orf20

Uncharacterized protein C3orf20

Also known as: CC020_HUMAN, DKFZP434N1817

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

Protein identityUniProt · HPA

UniProt accession
Q8ND61
Gene
C3orf20
Ensembl
ENSG00000131379
Chromosome
3
Canonical length
904 aa
Protein class
Predicted intracellular proteins
Subcellular location
Plasma membrane,Cytosol

OverviewNCBI Gene

Located in cytoplasm. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

904 residues, UniProt reviewed canonical sequence.

>Q8ND61|C3orf20
     1  MSYIKSNLEL YQQYTAMAPK LLARISKLLM ICQNAGISVP KGIRNIFEFT WEELISDPSV
    61  PTPSDILGLE VSFGAPLVVL MEPTFVQVPT LKKPLPPPPP APPRPVLLAT TGAAKRSTLS
   121  PTMARQVRTH QETLNRFQQQ SIHLLTELLR LKMKAMVESM SVGANPLDIT RRFVEASQLL
   181  HLNAKEMAFN CLISTAGRSG YSSGQLWKES LANMSAIGVN SPYQLIYHSS TACLSFSLSA
   241  GKEAKKKIGK SRTTEDVSMP PLHRGVGTPA NSLEFSDPCP EAREKLQELC RHIEAERATW
   301  KGRNISYPMI LRNYKAKMPS HLMLARKGDS QTPGLHYPPT AGAQTLSPTS HPSSANHHFS
   361  QHCQEGKAPK KAFKFHYTFY DGSSFVYYPS GNVAVCQIPT CCRGRTITCL FNDIPGFSLL
   421  ALFNTEGQGC VHYNLKTSCP YVLILDEEGG TTNDQQGYVV HKWSWTSRTE TLLSLEYKVN
   481  EEMKLKVLGQ DSITVTFTSL NETVTLTVSA NNCPHGMAYD KRLNRRISNM DDKVYKMSRA
   541  LAEIKKRFQK TVTQFINSIL LAAGLFTIEY PTKKEEEEFV RFKMRSRTHP ERLPKLSLYS
   601  GESLLRSQSG HLESSIAETL KDEPESAPVS PVRKTTKIHT KAKVTSRGKA REGRSPTRWA
   661  ALPSDCPLVL RKLMLKEDTR AGCKCLVKAP LVSDVELERF LLAPRDPSQV LVFGIISSQN
   721  YTSTGQLQWL LNTLYNHQQR GRGSPCIQCR YDSYRLLQYD LDSPLQEDPP LMVKKNSVVQ
   781  GMILMFAGGK LIFGGRVLNG YGLSKQNLLK QIFRSQQDYK MGYFLPDDYK FSVPNSVLSL
   841  EDSESVKKAE SEDIQGSSSS LALEDYVEKE LSLEAEKTRE PEVELHPLSR DSKITSWKKQ
   901  ASKK

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C3orf20 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
Intracellular
Secreted
No
Transmembrane segments
1
Mean surface accessibility (rSASA)
0.5
Highest tissue expression
6.2 nTPM

Expression across tissuesHPA

Tissue

  • testis: 6.2 nTPM
  • retina: 0.4 nTPM
  • bone marrow: 0.3 nTPM
  • tonsil: 0.3 nTPM
  • lymph node: 0.2 nTPM
  • appendix: 0.1 nTPM

Single-cell type

  • late spermatids: 65 nCPM
  • neutrophils: 30 nCPM
  • early spermatids: 28 nCPM
  • late primary spermatocytes: 23 nCPM
  • medullary thymic epithelial cells: 17 nCPM
  • thymocytes: 16 nCPM

Immune cell

  • naive CD8 T-cell: 0.1 nTPM
  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM

Brain region

  • white matter: 1.9 nTPM
  • cerebral cortex: 1.8 nTPM
  • pons: 1.7 nTPM
  • basal ganglia: 1.5 nTPM
  • midbrain: 1.5 nTPM
  • hippocampal formation: 1.4 nTPM

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)
1.14
gnomAD pLI
0
gnomAD missense Z
0.43
DepMap mean gene effect
0.07
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C3orf20 as an antibody target. Whether an autoantibody or antibody against C3orf20 could matter depends on whether native C3orf20 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C3orf20 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label C3orf20 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C3orf20. 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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