USP7 Gene
Introduction
The USP7 gene (Ubiquitin-Specific Peptidase 7, also known as HAUSP) encodes a deubiquitinating enzyme (DUB) that removes ubiquitin from target proteins, regulating their stability and function. USP7 is a master regulator of protein stability with roles in DNA damage response, epigenetics, and neuronal proteostasis.
Overview
flowchart TD
USP7["USP7"] -->|"involved in"| Autophagy["Autophagy"]
USP7["USP7"] -->|"modifies"| AMBRA1["AMBRA1"]
USP7["USP7"] -->|"deubiquitinates"| Ubiquitinated_proteins["Ubiquitinated proteins"]
USP7["USP7"] -->|"modifies"| UBA52["UBA52"]
USP7["USP7"] -->|"involved in"| Neural_Stem_Cell_Maintenance["Neural Stem Cell Maintenance"]
USP7["USP7"] -->|"regulates"| neural_stem_cell_maintenance["neural stem cell maintenance"]
USP7["USP7"] -->|"interacts with"| UBA52["UBA52"]
USP7["USP7"] -->|"participates in"| ubiquitin_proteasome["ubiquitin-proteasome"]
USP7["USP7"] -->|"associated with"| miR_522["miR-522"]
USP7["USP7"] -->|"inhibits"| Tumor["Tumor"]
USP7["USP7"] -->|"associated with"| Cancer["Cancer"]
USP7["USP7"] -->|"regulates"| UBIQUITINATION["UBIQUITINATION"]
USP7["USP7"] -->|"inhibits"| Ferroptosis["Ferroptosis"]
USP7["USP7"] -->|"inhibits"| Cancer["Cancer"]
style USP7 fill:#4fc3f7,stroke:#333,color:#000
...USP7 Gene
Introduction
The USP7 gene (Ubiquitin-Specific Peptidase 7, also known as HAUSP) encodes a deubiquitinating enzyme (DUB) that removes ubiquitin from target proteins, regulating their stability and function. USP7 is a master regulator of protein stability with roles in DNA damage response, epigenetics, and neuronal proteostasis.
Overview
Mermaid diagram (expand to render)
The USP7 gene is located on chromosome 16p13.2 and encodes a 128 kDa cysteine protease that cleaves ubiquitin from diverse substrates<sup>[1]</sup>. USP7 is one of approximately 100 DUBs in the human genome and is among the most extensively studied due to its central roles in stabilizing [p53](/proteins/p53-protein), MDM2, and numerous epigenetic regulators<sup>[2]</sup>. In the nervous system, USP7 regulates synaptic protein turnover, neuronal survival signaling, and chromatin remodeling essential for neural development and maintenance<sup>[3]</sup>. [@kategaya2017]
<div class="infobox infobox-gene"> [@fountain2019]
| | | [@hao2015]
|---|---| [@turnbull2017]
| Gene Symbol | USP7 |
| Full Name | Ubiquitin-Specific Peptidase 7 |
| Aliases | HAUSP (Herpesvirus-Associated USP) |
| Chromosomal Location | 16p13.2 |
| NCBI Gene ID | [7874](https://www.ncbi.nlm.nih.gov/gene/7874) |
| OMIM | [602519](https://omim.org/entry/602519) |
| Ensembl | [ENSG00000187555](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000187555) |
| UniProt | [Q93009](https://www.uniprot.org/uniprot/Q93009) |
| Associated Diseases | Hao-Fountain syndrome (NDD), cancer, neurodegeneration |
</div>
Function
Deubiquitinating Activity
USP7 removes ubiquitin from target proteins, preventing their proteasomal degradation<sup>[1]</sup>:
- Substrate diversity: USP7 deubiquitinates >70 known substrates across multiple pathways
- Ubiquitin chain specificity: Cleaves K48-linked (proteasomal targeting), K63-linked (signaling), and monoubiquitin
- Catalytic mechanism: Cysteine protease using Cys223-His464-Asp481 catalytic triad
- Regulation: Activity modulated by allosteric regulators (GMP synthetase, DNMT1)
Key Substrates and Pathways
USP7 stabilizes proteins in several critical pathways<sup>[2]</sup>:
- p53/MDM2 axis: Deubiquitinates both p53 and MDM2; net effect context-dependent
- Epigenetic regulation: Stabilizes [DNMT1](/genes/dnmt1), UHRF1, and Polycomb group proteins (BMI1, MEL18, RING1B)
- DNA damage response: Stabilizes CHFR, RNF168, and claspin for checkpoint activation
- Immune signaling: Deubiquitinates FOXP3 in Tregs, [NF-κB](/mechanisms/nf-kb-signaling-neurodegeneration) pathway components
- Wnt signaling: Stabilizes β-catenin via deubiquitination of Axin
Neuronal Functions
USP7 has specific roles in the nervous system<sup>[3]</sup>:
- Synaptic protein regulation: Controls turnover of postsynaptic density proteins
- Neural development: Required for proper neural crest and brain development
- Chromatin remodeling: Maintains epigenetic marks critical for neuronal gene expression
- Protein quality control: Balances ubiquitination/deubiquitination of neuronal proteome
- [REST](/genes/rest) regulation: Stabilizes REST/NRSF transcription factor in non-neuronal cells
Disease Associations
Heterozygous loss-of-function variants in USP7 cause a recognizable neurodevelopmental syndrome<sup>[4]</sup>:
| Feature | Frequency |
|---------|-----------|
| Intellectual disability | >90% (mild to moderate) |
| Speech/language delay | >90% |
| Autism spectrum features | ~60% |
| Seizures | ~30% |
| Feeding difficulties | ~70% |
| Hypogonadism | ~50% (males) |
| Behavioral issues | >80% (anxiety, ADHD-like) |
The mechanism involves haploinsufficiency affecting epigenetic regulation and synaptic protein stability<sup>[4]</sup>.
Cancer
USP7 is a therapeutic target in oncology<sup>[5]</sup>:
- Overexpression: Common in many cancers; stabilizes MDM2, suppressing p53
- Therapeutic inhibitors: Small-molecule USP7 inhibitors (GNE-6776, FT671, FT827) restore p53-mediated tumor suppression
- Epigenetic cancer drivers: USP7 stabilizes Polycomb proteins that silence tumor suppressors
Neurodegeneration Relevance
USP7 connects to neurodegenerative disease through several mechanisms<sup>[3]</sup>:
- [Alzheimer's disease](/diseases/alzheimers-disease): USP7 deubiquitinates [tau](/proteins/tau), potentially protecting it from degradation — contributing to tangle formation
- Proteostasis balance: USP7 activity must be balanced with [UBA1](/genes/uba1)-initiated ubiquitination for proper protein turnover
- Epigenetic dysregulation: USP7 substrates (DNMT1, Polycomb) regulate neuronal gene silencing programs altered in neurodegeneration
- Aging: USP7 expression changes with aging may contribute to proteostasis decline
Common Variants
| Variant | Effect | Phenotype |
|---------|--------|-----------|
| Heterozygous LoF (various) | Haploinsufficiency | Hao-Fountain syndrome |
| p.C223A | Catalytic dead | Loss of deubiquitinase activity (used experimentally) |
| Missense in catalytic domain | Reduced activity | Variable NDD phenotype |
| Missense in TRAF/UBL domains | Altered substrate binding | Milder developmental phenotype |
Expression
USP7 is broadly expressed with notable enrichment in<sup>[1]</sup>:
- Brain: High expression throughout [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), and [cerebellum](/brain-regions/cerebellum)
- Nucleus: Primary localization in nuclear bodies and chromatin
- Testis: High expression (relevant to hypogonadism in Hao-Fountain syndrome)
- Immune cells: T cells, macrophages (Treg regulation)
- Developing brain: Very high during embryonic neurogenesis
Therapeutic Implications
- USP7 inhibitors: Developed primarily for cancer; must consider neurotoxicity risk given NDD phenotype of LoF
- [Tau](/proteins/tau) deubiquitination: Selective modulation of USP7 activity toward tau could enhance tau clearance in AD
- Epigenetic therapy: USP7-dependent chromatin regulation as target for cognitive dysfunction
- Neuroprotection: Careful dosing of USP7 modulation needed — too much inhibition causes developmental defects
See Also
- [Ubiquitin-Proteasome System](/mechanisms/ubiquitin-proteasome-system)
- [UBA1 Gene](/genes/uba1)
- [Tau Protein](/proteins/tau)
- [DNMT1 Gene](/genes/dnmt1)
- [Epigenetic Mechanisms in Neurodegeneration](/mechanisms/epigenetic-mechanisms-neurodegeneration)
External Links
- [USP7 - NCBI Gene](https://www.ncbi.nlm.nih.gov/gene/7874)
- [USP7 - UniProt](https://www.uniprot.org/uniprot/Q93009)
- [USP7 - OMIM](https://omim.org/entry/602519)
Brain Atlas Resources
- [Allen Human Brain Atlas - USP7 Expression](https://human.brain-map.org/microarray/search/show?search_term=USP7)
- [Allen Cell Type Atlas](https://celltypes.brain-map.org/)
- [BrainSpan Atlas of the Developing Human Brain](https://brainspan.org/)
References
[Hu M et al., Crystal structure of a UBP-family deubiquitinating enzyme in isolation and in complex with ubiquitin aldehyde (2002) (2002)](https://doi.org/10.1016/S0092-8674(02)
[Kategaya L et al., USP7 small-molecule inhibitors interfere with ubiquitin binding (2017) (2017)](https://doi.org/10.1038/nature24006)
[Fountain MD et al., Pathogenic variants in USP7 cause a neurodevelopmental disorder with speech delays, altered behavior, and neurologic anomalies (2019) (2019)](https://doi.org/10.1038/s41436-019-0433-1)
[Hao YH et al., USP7 acts as a molecular rheostat to promote WASH-dependent endosomal protein recycling and is mutated in a human neurodevelopmental disorder (2015) (2015)](https://doi.org/10.1016/j.molcel.2015.09.033)
[Turnbull AP et al., Molecular basis of USP7 inhibition by selective small-molecule inhibitors (2017) (2017)](https://doi.org/10.1038/nature24451)Pathway Diagram
The following diagram shows the key molecular relationships involving USP7 Gene discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)