Seroatlas · Human Serome Atlas

C1QBP

Complement component 1 Q subcomponent-binding protein, mitochondrial

Also known as: C1QBP_HUMAN, gC1Q-R, gC1qR, HABP1, p32, SF2p32

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

Protein identityUniProt · HPA

UniProt accession
Q07021
Gene
C1QBP
Ensembl
ENSG00000108561
Chromosome
17
Canonical length
282 aa
Protein class
Cancer-related genes, Disease related genes, Human disease related genes, Plasma proteins, Potential drug targets, Predicted intracellular proteins, Predicted secreted proteins, Transporters
Subcellular location
Plasma membrane,Mitochondria
Secretome location
Secreted to blood
Quaternary structure
Homotrimer

OverviewNCBI Gene

The human complement subcomponent C1q associates with C1r and C1s in order to yield the first component of the serum complement system. The protein encoded by this gene is known to bind to the globular heads of C1q molecules and inhibit C1 activation. This protein has also been identified as the p32 subunit of pre-mRNA splicing factor SF2, as well as a hyaluronic acid-binding protein. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

282 residues, UniProt reviewed canonical sequence.

>Q07021|C1QBP
     1  MLPLLRCVPR VLGSSVAGLR AAAPASPFRQ LLQPAPRLCT RPFGLLSVRA GSERRPGLLR
    61  PRGPCACGCG CGSLHTDGDK AFVDFLSDEI KEERKIQKHK TLPKMSGGWE LELNGTEAKL
   121  VRKVAGEKIT VTFNINNSIP PTFDGEEEPS QGQKVEEQEP ELTSTPNFVV EVIKNDDGKK
   181  ALVLDCHYPE DEVGQEDEAE SDIFSIREVS FQSTGESEWK DTNYTLNTDS LDWALYDHLM
   241  DFLADRGVDN TFADELVELS TALEHQEYIT FLEDLKSFVK SQ

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against C1QBP 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)
0.46
Highest tissue expression
247 nTPM

Expression across tissuesHPA

Tissue

  • choroid plexus: 247 nTPM
  • skeletal muscle: 163 nTPM
  • tongue: 149 nTPM
  • esophagus: 134 nTPM
  • rectum: 133 nTPM
  • colon: 131 nTPM

Single-cell type

  • esophageal basal cells: 790 nCPM
  • esophageal suprabasal cells: 627 nCPM
  • gastric progenitor cells: 552 nCPM
  • migrating cytotrophoblasts: 545 nCPM
  • extravillous trophoblasts: 454 nCPM
  • oocytes: 405 nCPM

Immune cell

  • total PBMC: 433 nTPM
  • myeloid DC: 390 nTPM
  • memory B-cell: 331 nTPM
  • plasmacytoid DC: 326 nTPM
  • naive B-cell: 291 nTPM
  • naive CD4 T-cell: 291 nTPM

Brain region

  • choroid plexus: 129 nTPM
  • white matter: 81 nTPM
  • hypothalamus: 74 nTPM
  • medulla oblongata: 74 nTPM
  • spinal cord: 72 nTPM
  • midbrain: 71 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about C1QBP.

Disease | AllUniProt

Conditions C1QBP is implicated in, by any mechanism.

  • Combined oxidative phosphorylation deficiency 33 (COXPD33) MIM:617713

Disease | GeneticClinVar

12 pathogenic / likely-pathogenic of 212 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

ReferencesPubMed · IEDB

Publications for C1QBP from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Reference: AutoantibodyPubMed

2 publications

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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)
1.47
gnomAD pLI
0
gnomAD missense Z
1.06
DepMap mean gene effect
-0.4
DepMap dependency class
selective

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

  • Mitochondrial glycoprotein
  • Mitochondrial glycoprotein superfamily
  • Mitochondrial glycoprotein

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of C1QBP in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads C1QBP as an antibody target. Whether an autoantibody or antibody against C1QBP could matter depends on whether native C1QBP is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

C1QBP is annotated at the cell surface, where native C1QBP 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 C1QBP as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/C1QBP. 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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