CBX5: Chromobox Protein Homolog 5 – A Key Epigenetic Regulator
Comprehensive gene card for CBX5 (HP1α), including expression, mutations, and disease associations.
Gene Information Card
| Symbol | CBX5 |
|---|---|
| Full Name | Chromobox 5 |
| Gene Type | Protein coding |
| Chromosomal Location | 12q13.13 |
| NCBI Gene ID | 23468 ncbi.nlm.nih.gov/gene/23468 |
| Ensembl ID | ENSG00000111276 |
| UniProt ID | P45973 |
| OMIM ID | 604478 |
| HGNC ID | 1555 |
| Aliases | HP1α, HP1-HS-alpha, MGC1639 |
Description
CBX5 encodes chromobox protein homolog 5, also known as heterochromatin protein 1 alpha (HP1α). This protein is a key component of heterochromatin, involved in gene silencing, chromatin compaction, and epigenetic regulation. It binds to methylated histone H3 lysine 9 (H3K9me) via its chromodomain and recruits other silencing factors. CBX5 plays roles in cell cycle control, DNA repair, and transcriptional repression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cancer (various types) | Dysregulation of CBX5 expression alters heterochromatin stability and gene silencing, promoting tumorigenesis. | COSMIC, ClinVar |
| Breast cancer | Overexpression of CBX5 correlates with poor prognosis; may drive proliferation via aberrant chromatin silencing. | NCBI, PubMed |
| Prostate cancer | CBX5 upregulation linked to aggressive disease and metastasis. | COSMIC, PubMed |
| Hepatocellular carcinoma | CBX5 overexpression associated with tumor progression and reduced survival. | PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 28.5 | High |
| Bone marrow | 22.1 | High |
| Lymph node | 18.7 | Medium |
| Spleen | 16.3 | Medium |
| Brain | 8.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| K562 (leukemia) | 32.4 | High expression |
| HeLa (cervical) | 25.1 | High expression |
| A549 (lung) | 20.8 | Medium expression |
| MCF7 (breast) | 18.5 | Medium expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.1% | Potential loss of start codon; likely loss of function |
| c.154G>A (p.Glu52Lys) | Missense | <0.1% | Unknown significance; reported in COSMIC |
| c.421C>T (p.Arg141Trp) | Missense | <0.1% | Rare; possibly damaging (in silico prediction) |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations in CBX5 are rare; they may impair heterochromatin formation and gene silencing.
Gain of Function (GOF)
Gain-of-function mutations are not well documented; overexpression is more common in cancer.
Dominant Negative (DN)
No dominant-negative mutations have been reported for CBX5.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Epigenetic regulation of gene expression (Reactome: R-HSA-212165)
• Chromatin modifying enzymes (Reactome: R-HSA-3247509)
• HP1-mediated heterochromatin formation (Reactome: R-HSA-2559580)
Protein Summary
CBX5 (HP1α) is a 191-amino-acid protein containing an N-terminal chromodomain and a C-terminal chromoshadow domain. It binds methylated histone H3K9 and self-associates to compact chromatin. HP1α is essential for heterochromatin maintenance, telomere stability, and mitotic progression. Post-translational modifications (e.g., phosphorylation) regulate its localization and function.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CBX5 Knockout HEK293 Cell Line | EDJ-KQ3155 | Human | 23468 | Details Get a Quote |
| CBX5 Knockout A-549 Cell Line | EDJ-KQ24553 | Human | 23468 | Details Get a Quote |
| CBX5 Knockout HCT 116 Cell Line | EDJ-KQ24554 | Human | 23468 | Details Get a Quote |
| CBX5 Knockout HeLa Cell Line | EDJ-KQ24555 | Human | 23468 | Details Get a Quote |
