Seroatlas · Human Serome Atlas

C3orf33

Protein C3orf33

Also known as: AC3-33, CC033_HUMAN, FLJ31139

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

Protein identityUniProt · HPA

UniProt accession: Q6P1S2
Gene: C3orf33
Ensembl: ENSG00000174928
Chromosome: 3
Canonical length: 294 aa
Protein class: Predicted intracellular proteins, Predicted membrane proteins, Predicted secreted proteins
Secretome location: Secreted in other tissues

OverviewNCBI Gene

Involved in negative regulation of ERK1 and ERK2 cascade and regulation of DNA-binding transcription factor activity. Located in extracellular space. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

294 residues, UniProt reviewed canonical sequence.

>Q6P1S2|C3orf33
     1  MAGQPAATGS PSADKDGMEP NVVARISQWA DDHLRLVRNI STGMAIAGIM LLLRSIRLTS
    61  KFTSSSDIPV EFIRRNVKLR GRLRRITENG LEIEHIPITL PIIASLRKEP RGALLVKLAG
   121  VELAETGKAW LQKELKPSQL LWFQLLGKEN SALFCYLLVS KGGYFSVNLN EEILRRGLGK
   181  TVLVKGLKYD SKIYWTVHRN LLKAELTALK KGEGIWKEDS EKESYLEKFK DSWREIWKKD
   241  SFLKTTGSDF SLKKESYYEK LKRTYEIWKD NMNNCSLILK FRELISRINF RRKG

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C3orf33 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: Secreted
Secreted: Yes
Transmembrane segments: 1
Mean surface accessibility (rSASA): 0.39
Highest tissue expression: 10 nTPM

Expression across tissuesHPA

Tissue

adrenal gland: 10 nTPM
thyroid gland: 8.1 nTPM
parathyroid gland: 7 nTPM
pancreas: 6.3 nTPM
kidney: 5.8 nTPM
heart muscle: 5.7 nTPM

Single-cell type

oocytes: 28 nCPM
bergmann glia: 27 nCPM
ependymal cells: 26 nCPM
other brain neurons: 25 nCPM
brain excitatory neurons: 24 nCPM
brain inhibitory neurons: 22 nCPM

Immune cell

MAIT T-cell: 5.1 nTPM
NK-cell: 4.2 nTPM
naive CD8 T-cell: 4.1 nTPM
gdT-cell: 4 nTPM
naive CD4 T-cell: 3.9 nTPM
memory CD8 T-cell: 3.6 nTPM

Brain region

choroid plexus: 4.4 nTPM
cerebral cortex: 3.9 nTPM
hypothalamus: 3.2 nTPM
basal ganglia: 3 nTPM
hippocampal formation: 2.8 nTPM
thalamus: 2.8 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): 1.41
gnomAD pLI: 0
gnomAD missense Z: 0.41
DepMap mean gene effect: 0.15
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Cellular components

Protein domainsUniProt · Pfam · InterPro

SNase-like, OB-fold superfamily
Protein C3orf33-like

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C3orf33 as an antibody target. Whether an autoantibody or antibody against C3orf33 could matter depends on whether native C3orf33 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C3orf33 is annotated as secreted, so native C3orf33 circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label C3orf33 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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