Seroatlas · Human Serome Atlas

C1QC

Complement C1q subcomponent subunit C

Also known as: C1QC_HUMAN, C1QG

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

Protein identityUniProt · HPA

UniProt accession
P02747
Gene
C1QC
Ensembl
ENSG00000159189
Chromosome
1
Canonical length
245 aa
Protein class
Disease related genes, Human disease related genes, Plasma proteins, Predicted intracellular proteins, Predicted secreted proteins
Secretome location
Secreted to blood

OverviewNCBI Gene

This gene encodes the C-chain polypeptide of serum complement subcomponent C1q, which associates with C1r and C1s to yield the first component of the serum complement system. C1q is composed of 18 polypeptide chains which include 6 A-chains, 6 B-chains, and 6 C-chains. Each chain contains an N-terminal collagen-like region and a C-terminal C1q globular domain. C1q deficiency is associated with lupus erythematosus and glomerulonephritis. [provided by RefSeq, Dec 2016]

Canonical amino-acid sequenceUniProt

245 residues, UniProt reviewed canonical sequence.

>P02747|C1QC
     1  MDVGPSSLPH LGLKLLLLLL LLPLRGQANT GCYGIPGMPG LPGAPGKDGY DGLPGPKGEP
    61  GIPAIPGIRG PKGQKGEPGL PGHPGKNGPM GPPGMPGVPG PMGIPGEPGE EGRYKQKFQS
   121  VFTVTRQTHQ PPAPNSLIRF NAVLTNPQGD YDTSTGKFTC KVPGLYYFVY HASHTANLCV
   181  LLYRSGVKVV TFCGHTSKTN QVNSGGVLLR LQVGEEVWLA VNDYYDMVGI QGSDSVFSGF
   241  LLFPD

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C1QC 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
893 nTPM

Expression across tissuesHPA

Tissue

  • spleen: 893 nTPM
  • lymph node: 345 nTPM
  • lung: 273 nTPM
  • adipose tissue: 266 nTPM
  • placenta: 192 nTPM
  • adrenal gland: 184 nTPM

Single-cell type

  • kupffer cells: 3,478 nCPM
  • hofbauer cells: 2,312 nCPM
  • macrophages: 1,291 nCPM
  • microglia: 326 nCPM
  • cdc: 252 nCPM
  • monocytes: 186 nCPM

Immune cell

  • intermediate monocyte: 57 nTPM
  • non-classical monocyte: 10 nTPM
  • classical monocyte: 1.3 nTPM
  • total PBMC: 1.2 nTPM
  • neutrophil: 0.1 nTPM
  • basophil: 0 nTPM

Brain region

  • white matter: 294 nTPM
  • medulla oblongata: 219 nTPM
  • thalamus: 182 nTPM
  • pons: 180 nTPM
  • spinal cord: 168 nTPM
  • choroid plexus: 150 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about C1QC.

Disease | AllUniProt

Conditions C1QC is implicated in, by any mechanism.

Disease | GeneticClinVar

2 pathogenic / likely-pathogenic of 178 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Disease | ImmuneIEDB

Conditions an epitope on C1QC was assayed in.

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)
1.09
gnomAD pLI
0.05
gnomAD missense Z
0.43
DepMap mean gene effect
-0.01
DepMap dependency class
none

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

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C1QC as an antibody target. Whether an autoantibody or antibody against C1QC could matter depends on whether native C1QC is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C1QC is annotated at the cell surface, where native C1QC 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 C1QC as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C1QC. 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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