Seroatlas · Human Serome Atlas

C2orf81

Uncharacterized protein C2orf81

Also known as: CB081_HUMAN, hCG40743, LOC388963

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

Protein identityUniProt · HPA

UniProt accession: A6NN90
Gene: C2orf81
Ensembl: ENSG00000284308
Chromosome: 2
Canonical length: 582 aa
Protein class: Predicted intracellular proteins
Subcellular location: Nucleoplasm,Nucleoli,Nucleoli fibrillar center

OverviewNCBI Gene

Predicted to be involved in regulation of DNA-templated transcription. Predicted to be located in nucleus. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

582 residues, UniProt reviewed canonical sequence.

>A6NN90|C2orf81
     1  MAHEGSRQVR DRGVTRSKAE KVRPPTVPVP QVDIVPGRLS EAEWMALTAL EEGEDVVGDI
    61  LADLLARVMD SAFKVYLTQQ CIPFTISQAR EAMLQITEWR FLARDEGESA VAEDPTWGED
   121  EEPSACTTDS WAQGSVPVLH ASTSEGLENF QGEDPGGVDR IPLGRSWMGR GSQEQMESWE
   181  PSPQLRVTSA PPPTSELFQE AGPGGPVEEA DGQSRGLSSA GSLSASFQLS VEEAPADDAD
   241  PSLDPYLVAS PQASTGRGHP LGFHLSLEDL YCCMPQLDAA GDRLELRSEG VPCIASGVLV
   301  SYPSVGGATR PSASCQQQRA GHSDVRLSAH HHRMRRKAAV KRLDPARLPC HWVRPLAEVL
   361  VPDSQTRPLE AYRGRQRGEK TKARAEPQAL GPGTRVSPAA FFPLRPGIPF RDLDSGPALL
   421  FPTLNLGLSS PSLESKLPLP NSRIRFLTTH PVLPDVARSR SPKLWPSVRW PSGWEGKAEL
   481  LGELWAGRTR VPPQGLELAD REGQDPGRWP RTTPPVLEAT SQVMWKPVLL PEALKLAPGV
   541  SMWNRSTQVL LSSGVPEQED KEGSTFPPVE QHPIQTGAPK PR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C2orf81 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: Unknown
Secreted: No
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.68
Highest tissue expression: 18 nTPM

Expression across tissuesHPA

Tissue

fallopian tube: 18 nTPM
testis: 18 nTPM
pituitary gland: 12 nTPM
choroid plexus: 8.6 nTPM
parathyroid gland: 5.6 nTPM
hippocampal formation: 4.8 nTPM

Single-cell type

ependymal cells: 97 nCPM
choroid plexus epithelial cells: 23 nCPM
other brain neurons: 9.9 nCPM
brain excitatory neurons: 8 nCPM
brain inhibitory neurons: 8 nCPM
oligodendrocytes: 2.8 nCPM

Immune cell

plasmacytoid DC: 13 nTPM
memory B-cell: 6.7 nTPM
myeloid DC: 6.2 nTPM
naive B-cell: 5.9 nTPM
naive CD4 T-cell: 3.4 nTPM
NK-cell: 3.1 nTPM

Brain region

choroid plexus: 20 nTPM
midbrain: 12 nTPM
medulla oblongata: 12 nTPM
spinal cord: 8.6 nTPM
hippocampal formation: 7.9 nTPM
hypothalamus: 7.9 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): 0.8
gnomAD pLI: 0.13
gnomAD missense Z: 1.6

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

Protein domainsUniProt · Pfam · InterPro

Protein of unknown function DUF4639
Domain of unknown function (DUF4639)

KeywordsUniProt

Phosphoprotein

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C2orf81 as an antibody target. Whether an autoantibody or antibody against C2orf81 could matter depends on whether native C2orf81 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C2orf81 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 C2orf81 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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