HOPX Homeobox Gene: A Key Regulator of Cardiac and Placental Development
Comprehensive genomic and proteomic overview of HOPX, a non-DNA-binding homeodomain protein involved in cell differentiation and cancer.
Gene Information Card
| Symbol | HOPX |
|---|---|
| Full Name | HOP homeobox |
| Gene Type | Protein coding |
| Chromosomal Location | 4q12 |
| NCBI Gene ID | 84525 ncbi.nlm.nih.gov/gene/84525 |
| Ensembl ID | ENSG00000171476 |
| UniProt ID | Q9BPY8 |
| OMIM ID | 607275 |
| HGNC ID | 24922 |
| Aliases | HOP, OB1, LAGY, NECC1, SMAP31, TOTO |
Description
HOPX (HOP homeobox) encodes a homeodomain-containing protein that lacks DNA-binding activity. It acts as a transcriptional cofactor, modulating gene expression by interacting with serum response factor (SRF) and other transcription factors. HOPX is essential for cardiac development, placental trophoblast differentiation, and has been implicated as a tumor suppressor in various cancers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cardiac hypertrophy | HOPX modulates SRF-dependent gene expression; loss leads to hypertrophic cardiomyopathy | PMID: 12446788 |
| Placental insufficiency | HOPX deficiency disrupts trophoblast differentiation and placental vascularization | PMID: 20081193 |
| Lung cancer | HOPX promoter hypermethylation and reduced expression contribute to tumor progression | PMID: 23285129 |
| Gastric cancer | HOPX acts as a tumor suppressor; loss of expression correlates with poor prognosis | PMID: 25695626 |
| Colorectal cancer | HOPX downregulation promotes epithelial-mesenchymal transition and metastasis | PMID: 27323853 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 12.5 | Medium |
| Placenta | 8.2 | Medium |
| Lung | 3.1 | Low |
| Stomach | 2.8 | Low |
| Colon | 1.5 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| H9c2 (rat cardiomyoblasts) | 15.0 | High expression; used in cardiac differentiation studies |
| BeWo (human placental choriocarcinoma) | 9.4 | Moderate expression; trophoblast model |
| A549 (lung adenocarcinoma) | 0.8 | Low expression; consistent with tumor suppressor role |
| MCF7 (breast cancer) | 1.2 | Low 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% | Likely loss of start codon; predicted loss of function |
| c.124C>T (p.Arg42Trp) | Missense | <0.1% | Located in homeodomain; may disrupt protein interactions |
| c.256_257insA (p.Thr86Asnfs*5) | Frameshift | <0.1% | Truncating; loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported HOPX mutations are loss-of-function, including frameshift and nonsense variants that truncate the protein or disrupt the homeodomain.
Gain of Function (GOF)
No gain-of-function mutations have been documented in HOPX.
Dominant Negative (DN)
No dominant-negative mutations have been reported for HOPX.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Cardiac progenitor differentiation (SRF-HOPX pathway)
• Trophoblast differentiation (HOPX-GATA3 axis)
• Hippo signaling pathway (HOPX interacts with YAP/TAZ)
Protein Summary
HOPX is a 73-amino-acid protein containing a homeodomain that does not bind DNA. It functions as a transcriptional cofactor by interacting with SRF to regulate cardiac and smooth muscle gene expression. HOPX also modulates Hippo signaling via interaction with YAP/TAZ, influencing cell proliferation and differentiation. The protein is predominantly nuclear and expressed in heart, placenta, and certain epithelial tissues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| HOPX Knockout HEK293 Cell Line | EDJ-KQ10110 | Human | 84525 | Details Get a Quote |
| HOPX Knockout HeLa Cell Line | EDJ-KQ57608 | Human | 84525 | Details Get a Quote |
| HOPX Knockout A-549 Cell Line | EDJ-KQ66106 | Human | 84525 | Details Get a Quote |
| HOPX Knockout HCT 116 Cell Line | EDJ-KQ74526 | Human | 84525 | Details Get a Quote |
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