MDM4 (also known as MDMX or ** MDM4**) is a critical negative regulator of p53 and plays an important role in genome stability, cell cycle control, and tumor suppression. It is a member of the MDM family of proteins (MDM1, MDM2, MDM4) that regulate p53 activity.
| Property | Value |
|----------|-------|
| **Gene Symbol** | MDM4 (MDMX) |
| **Full Name** | MDM4 Proto-Oncogene |
| **Chromosomal Location** | 1q32.1 |
| **NCBI Gene ID** | 4193 |
| **OMIM** | 602673 |
| **Ensembl** | ENSG00000198625 |
| **UniProt** | O15151 |
| **Associated Diseases** | Retinoblastoma, Li-Fraumeni syndrome, breast cancer, melanoma, neurodegeneration |
MDM4 is a human gene whose product mDM4 is a nuclear protein that contains a p53-binding domain and functions primarily as a transcriptional repressor:. Variants in MDM4 have been implicated in Cancer, Neurodegeneration. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
MDM4 is a nuclear protein that contains a p53-binding domain and functions primarily as a transcriptional repressor:
- Direct Binding: MDM4 binds to p53 transactivation domain, inhibiting p53-mediated gene activation
- Protein Stability: Unlike MDM2, MDM4 does not ubiquitinate p53; instead it stabilizes p53 protein
- Feedback Regulation: p53 activates MDM4 expression, creating a balanced regulatory loop
- G1/S Transition: MDM4 overexpression promotes G1/S cell cycle progression
- S-Phase Entry: Modulates E2F1 activity for proper S-phase entry
- Checkpoint Response: Negatively regulates p53-dependent cell cycle arrest
- ATM Activation: Involved in ATM/ATR-mediated DNA damage response
- Chk2 Phosphorylation: Modulates checkpoint kinase activation
- Genomic Stability: Loss leads to increased genomic instability
- Oncogenic Driver: MDM4 amplification is common in various cancers
- Retinoblastoma: Germline MDM4 mutations predispose to retinoblastoma
- Melanoma: Frequently overexpressed in melanoma
- Breast Cancer: MDM4 overexpression correlates with poor prognosis
- Alzheimer's Disease: MDM4 is upregulated in AD brains and may affect neuronal apoptosis
- P53-mediated Neurodegeneration: Altered MDM4/p53 balance affects neuronal survival
- DNA Repair: MDM4 modulates DNA repair efficiency in neurons
MDM4 shows tissue-specific expression:
- High Expression: Embryonic tissues, testis, thymus
- Moderate Expression: Brain, heart, skeletal muscle
- Low/Restricted Expression: Most adult tissues
In the brain, MDM4 is expressed in neurons and glial cells.
- MDM4 Inhibitors: Small molecules targeting MDM4-p53 interaction in development
- Combination Therapy: MDM4 inhibitors with chemotherapy or radiation
- Understanding MDM4's role in neuronal apoptosis
- Targeting MDM4 in neurodegeneration