Seroatlas · Human Serome Atlas

C11orf21

Uncharacterized protein C11orf21

Also known as: CK021_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
Q9P2W6
Gene
C11orf21
Ensembl
ENSG00000110665
Chromosome
11
Canonical length
132 aa
Protein class
Predicted intracellular proteins
Subcellular location
Nucleoplasm,Cytosol

OverviewNCBI Gene

Predicted to be located in cytoplasm. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

132 residues, UniProt reviewed canonical sequence.

>Q9P2W6|C11orf21
     1  MGRTWCGMWR RRRPGRRSAV PRWPHLSSQS GVEPPDRWTG TPGWPSRDQE APGSMMPPAA
    61  AQPSAHGALV PPATAHEPVD HPALHWLACC CCLSLPGQLP LAIRLGWDLD LEAGPSSGKL
   121  CPRARRWQPL PS

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C11orf21 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
0
Mean surface accessibility (rSASA)
0.69
Highest tissue expression
48 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 48 nTPM
  • heart muscle: 19 nTPM
  • spleen: 15 nTPM
  • lymph node: 13 nTPM
  • tonsil: 6.9 nTPM
  • appendix: 6.7 nTPM

Single-cell type

  • cardiomyocytes: 222 nCPM
  • platelets: 92 nCPM
  • megakaryocytes: 74 nCPM
  • neutrophil progenitors: 53 nCPM
  • nk-cells: 30 nCPM
  • monocyte progenitors: 25 nCPM

Immune cell

  • basophil: 81 nTPM
  • non-classical monocyte: 59 nTPM
  • eosinophil: 46 nTPM
  • intermediate monocyte: 31 nTPM
  • NK-cell: 24 nTPM
  • gdT-cell: 24 nTPM

Brain region

  • medulla oblongata: 2.5 nTPM
  • white matter: 2.5 nTPM
  • pons: 2 nTPM
  • spinal cord: 1.6 nTPM
  • midbrain: 1.5 nTPM
  • thalamus: 1.3 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)
1.08
gnomAD pLI
0.02
gnomAD missense Z
0.98
DepMap mean gene effect
0.03
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

  • Protein of unknown function DUF4620
  • Domain of unknown function (DUF4620)

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C11orf21 as an antibody target. Whether an autoantibody or antibody against C11orf21 could matter depends on whether native C11orf21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C11orf21 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 C11orf21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C11orf21. 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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