MDM2 Gene

title: MDM2 Gene

MDM2 (MDM2 Proto-Oncogene)

Overview

MDM2 encodes an E3 ubiquitin ligase that is the primary regulator of p53 tumor suppressor protein. While classically studied in cancer, MDM2-p53 pathway plays complex roles in neuronal survival, DNA damage responses, and neurodegenerative diseases. [@tan2018]

Introduction

MDM2 (Mouse Double Minute 2 Homolog) is a key negative regulator of p53, the guardian of the genome. The MDM2-p53 axis is one of the most important pathways in cell biology, controlling cell cycle, [apoptosis](/entities/apoptosis), and DNA repair. In [neurons](/entities/neurons), this pathway has additional implications for neurodegeneration, as p53 has both pro-survival and pro-death functions depending on context. [@zhang2009]

<div class="infobox infobox-gene">

| Property | Value |
|----------|-------|
| Gene Symbol | MDM2 |
| Full Name | MDM2 Proto-Oncogene, E3 Ubiquitin Protein Ligase |
| Chromosomal Location | 12q15 |
| NCBI Gene ID | 4193 |
| OMIM ID | 164785 |
| Ensembl ID | ENSG00000135679 |
| UniProt ID | Q00978 |
| Encoded Protein | MDM2 protein |
| Associated Diseases | Li-Fraumeni syndrome, various cancers, Alzheimer's disease, Parkinson's disease |

</div>

Function

MDM2 is a RING-finger E3 ubiquitin ligase with multiple functions:

p53 Regulation (Primary Function)

• Catalyzes p53 ubiquitination and degradation
• Nuclear export of p53
• Inhibits p53 transcriptional activity
• Negative feedback loop: p53 activates MDM2 expression

...

title: MDM2 Gene

MDM2 (MDM2 Proto-Oncogene)

Overview

MDM2 encodes an E3 ubiquitin ligase that is the primary regulator of p53 tumor suppressor protein. While classically studied in cancer, MDM2-p53 pathway plays complex roles in neuronal survival, DNA damage responses, and neurodegenerative diseases. [@tan2018]

Introduction

MDM2 (Mouse Double Minute 2 Homolog) is a key negative regulator of p53, the guardian of the genome. The MDM2-p53 axis is one of the most important pathways in cell biology, controlling cell cycle, [apoptosis](/entities/apoptosis), and DNA repair. In [neurons](/entities/neurons), this pathway has additional implications for neurodegeneration, as p53 has both pro-survival and pro-death functions depending on context. [@zhang2009]

<div class="infobox infobox-gene">

| Property | Value |
|----------|-------|
| Gene Symbol | MDM2 |
| Full Name | MDM2 Proto-Oncogene, E3 Ubiquitin Protein Ligase |
| Chromosomal Location | 12q15 |
| NCBI Gene ID | 4193 |
| OMIM ID | 164785 |
| Ensembl ID | ENSG00000135679 |
| UniProt ID | Q00978 |
| Encoded Protein | MDM2 protein |
| Associated Diseases | Li-Fraumeni syndrome, various cancers, Alzheimer's disease, Parkinson's disease |

</div>

Function

MDM2 is a RING-finger E3 ubiquitin ligase with multiple functions:

p53 Regulation (Primary Function)

• Catalyzes p53 ubiquitination and degradation
• Nuclear export of p53
• Inhibits p53 transcriptional activity
• Negative feedback loop: p53 activates MDM2 expression

p53-Independent Functions

• Ubiquitinates other targets: FOXO, [NF-κB](/entities/nf-kb), p73
• Regulates DNA repair proteins
• Controls cell cycle progression
• May have E3 ligase-independent functions

In Neurons

• Responds to neuronal DNA damage
• Controls neuronal apoptosis
• Regulates synaptic plasticity
• May affect age-related neurodegeneration

Disease Associations

Alzheimer's Disease

• MDM2 expression is altered in AD brains
• p53-mediated apoptosis contributes to neuronal loss
• MDM2-p53 axis may be dysregulated
• Some MDM2 polymorphisms affect AD risk

Parkinson's Disease

• MDM2 protects against dopaminergic neuron death
• p53 can promote or inhibit PD pathology
• Mitochondrial dysfunction involves MDM2
• Therapeutic targeting is being explored

ALS

• MDM2 expression is altered in ALS
• Motor neuron survival involves p53 pathways
• DNA damage responses are impaired in ALS

Expression

MDM2 has widespread expression:

• Highest expression: Heart, brain, skeletal muscle
• Ubiquitous: Most tissues
• Cellular localization: Predominantly nuclear

In the brain:

• Expressed in neurons and glia
• Higher expression in [cortex](/brain-regions/cortex) and [hippocampus](/brain-regions/hippocampus)
• Regulated by neuronal activity

Key Publications

[Marine & Lozano, MDM2-mediated p53 degradation (2010)](https://doi.org/10.1101/gad.1921710)

[Oren, MDM2: the role in apoptosis and cancer (2003)](https://doi.org/10.1038/nrc1070)

[Sliwinska et al., MDM2-p53 in neurodegeneration (2016)](https://doi.org/10.1016/j.neuropharm.2015.08.032)

[Tan et al., MDM2 in neuronal death and disease (2018)](https://doi.org/10.1007/s12035-017-0826-6)

Cross-Links

• [MDM2](/proteins/mdm2-protein) - The protein product
• [TP53](/genes/tp53) - p53 tumor suppressor
• [p53 pathway](/mechanisms/p53-pathway) - Cell death pathway
• [DNA repair](/mechanisms/dna-repair-neurodegeneration)) - MDM2 role in DNA repair
• [Alzheimer's disease](/diseases/alzheimers-disease) - Disease association
• [Parkinson's disease](/diseases/parkinsons-disease) - Disease association

See Also

• [Neurodegeneration](/diseases/neurodegeneration) — General mechanisms

External Links

• [GeneCards](https://www.genecards.org/)
• [NCBI Gene](https://www.ncbi.nlm.nih.gov/gene/)

References

[Unknown, Marine & Lozano, MDM2 and p53 in cancer (2010) (2010)](https://doi.org/10.1101/gad.1921710)

[Unknown, Oren, MDM2: the guardian of the genome (2003) (2003)](https://doi.org/10.1038/nrc1070)

[Sliwinska et al., MDM2-p53 axis in neurodegenerative diseases (2016) (2016)](https://doi.org/10.1016/j.neuropharm.2015.08.032)

[Tan et al., MDM2 functions in neurons (2018) (2018)](https://doi.org/10.1007/s12035-017-0826-6)

[Unknown, Zhang & Lu, MDM2/p53 in neuronal apoptosis (2009) (2009)](https://doi.org/10.1016/j.neuroscience.2009.01.023)

Pathway Diagram

Pathway Diagram

The following diagram shows the key molecular relationships involving MDM2 Gene discovered through SciDEX knowledge graph analysis: