Seroatlas · Human Serome Atlas

CBX3

Chromobox protein homolog 3

Also known as: CBX3_HUMAN, HP1Hs-gamma

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

Protein identityUniProt · HPA

UniProt accession
Q13185
Gene
CBX3
Ensembl
ENSG00000122565
Chromosome
7
Canonical length
183 aa
Protein class
Plasma proteins, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Nuclear bodies

OverviewNCBI Gene

At the nuclear envelope, the nuclear lamina and heterochromatin are adjacent to the inner nuclear membrane. The protein encoded by this gene binds DNA and is a component of heterochromatin. This protein also can bind lamin B receptor, an integral membrane protein found in the inner nuclear membrane. The dual binding functions of the encoded protein may explain the association of heterochromatin with the inner nuclear membrane. This protein binds histone H3 tails methylated at Lys-9 sites. This protein is also recruited to sites of ultraviolet-induced DNA damage and double-strand breaks. Two transcript variants encoding the same protein but differing in the 5' UTR, have been found for this gene.[provided by RefSeq, Mar 2011]

Canonical amino-acid sequenceUniProt

183 residues, UniProt reviewed canonical sequence.

>Q13185|CBX3
     1  MASNKTTLQK MGKKQNGKSK KVEEAEPEEF VVEKVLDRRV VNGKVEYFLK WKGFTDADNT
    61  WEPEENLDCP ELIEAFLNSQ KAGKEKDGTK RKSLSDSESD DSKSKKKRDA ADKPRGFARG
   121  LDPERIIGAT DSSGELMFLM KWKDSDEADL VLAKEANMKC PQIVIAFYEE RLTWHSCPED
   181  EAQ

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CBX3 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)
0.46
Highest tissue expression
177 nTPM

Expression across tissuesHPA

Tissue

  • thymus: 177 nTPM
  • bone marrow: 159 nTPM
  • lymph node: 136 nTPM
  • tonsil: 132 nTPM
  • retina: 114 nTPM
  • duodenum: 100 nTPM

Single-cell type

  • megakaryocytes: 495 nCPM
  • differentiating spermatogonia: 479 nCPM
  • extravillous trophoblasts: 467 nCPM
  • megakaryocyte progenitors: 402 nCPM
  • monocyte progenitors: 399 nCPM
  • erythrocyte progenitors: 389 nCPM

Immune cell

  • T-reg: 149 nTPM
  • eosinophil: 138 nTPM
  • basophil: 137 nTPM
  • non-classical monocyte: 124 nTPM
  • naive CD8 T-cell: 120 nTPM
  • naive CD4 T-cell: 119 nTPM

Brain region

  • hypothalamus: 66 nTPM
  • white matter: 66 nTPM
  • midbrain: 62 nTPM
  • spinal cord: 60 nTPM
  • medulla oblongata: 60 nTPM
  • pons: 56 nTPM

ReferencesPubMed · IEDB

Publications for CBX3 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

3 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)
0.67
gnomAD pLI
0.41
gnomAD missense Z
1.93
DepMap mean gene effect
-0.1
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 10% 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

InteractionsUniProt · HPA

Protein binding partners of CBX3 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 CBX3 as an antibody target. Whether an autoantibody or antibody against CBX3 could matter depends on whether native CBX3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CBX3 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 CBX3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CBX3. 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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