Seroatlas · Human Serome Atlas

CBX5

Chromobox protein homolog 5

Also known as: CBX5_HUMAN, HP1, HP1-ALPHA, HP1Hs-alpha

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

Protein identityUniProt · HPA

UniProt accession
P45973
Gene
CBX5
Ensembl
ENSG00000094916
Chromosome
12
Canonical length
191 aa
Protein class
Predicted intracellular proteins
Subcellular location
Nucleoplasm
Quaternary structure
Homodimer

OverviewNCBI Gene

This gene encodes a highly conserved nonhistone protein, which is a member of the heterochromatin protein family. The protein is enriched in the heterochromatin and associated with centromeres. The protein has a single N-terminal chromodomain which can bind to histone proteins via methylated lysine residues, and a C-terminal chromo shadow-domain (CSD) which is responsible for the homodimerization and interaction with a number of chromatin-associated nonhistone proteins. The encoded product is involved in the formation of functional kinetochore through interaction with essential kinetochore proteins. The gene has a pseudogene located on chromosome 3. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

191 residues, UniProt reviewed canonical sequence.

>P45973|CBX5
     1  MGKKTKRTAD SSSSEDEEEY VVEKVLDRRV VKGQVEYLLK WKGFSEEHNT WEPEKNLDCP
    61  ELISEFMKKY KKMKEGENNK PREKSESNKR KSNFSNSADD IKSKKKREQS NDIARGFERG
   121  LEPEKIIGAT DSCGDLMFLM KWKDTDEADL VLAKEANVKC PQIVIAFYEE RLTWHAYPED
   181  AENKEKETAK S

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CBX5 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)
0.48
Highest tissue expression
112 nTPM

Expression across tissuesHPA

Tissue

  • choroid plexus: 112 nTPM
  • thymus: 29 nTPM
  • cerebral cortex: 25 nTPM
  • parathyroid gland: 24 nTPM
  • testis: 24 nTPM
  • thyroid gland: 22 nTPM

Single-cell type

  • choroid plexus epithelial cells: 511 nCPM
  • late primary spermatocytes: 312 nCPM
  • megakaryocyte progenitors: 207 nCPM
  • corticotrophs: 207 nCPM
  • erythrocyte progenitors: 200 nCPM
  • early primary spermatocytes: 163 nCPM

Immune cell

  • plasmacytoid DC: 22 nTPM
  • naive B-cell: 14 nTPM
  • memory B-cell: 12 nTPM
  • T-reg: 10 nTPM
  • myeloid DC: 9.4 nTPM
  • non-classical monocyte: 8.2 nTPM

Brain region

  • choroid plexus: 275 nTPM
  • hypothalamus: 138 nTPM
  • white matter: 114 nTPM
  • midbrain: 112 nTPM
  • spinal cord: 110 nTPM
  • thalamus: 109 nTPM

ReferencesPubMed · IEDB

Publications for CBX5 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

1 publication

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)
0.35
gnomAD pLI
0.93
gnomAD missense Z
2.53
DepMap mean gene effect
-0.16
DepMap dependency class
selective

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).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CBX5 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 CBX5 as an antibody target. Whether an autoantibody or antibody against CBX5 could matter depends on whether native CBX5 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CBX5 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 CBX5 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CBX5. 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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