| RPL23 Gene |
|---|
| Gene Symbol | RPL23 |
| Full Name | Ribosomal Protein L23 |
| Chromosomal Location | 17q21.31 |
| NCBI Gene ID | [9349](https://www.ncbi.nlm.nih.gov/gene/9349) |
| OMIM | [604563](https://www.omim.org/entry/604563) |
| Ensembl ID | ENSG00000125691 |
| UniProt ID | [P62829](https://www.uniprot.org/uniprot/P62829) |
| Protein Size | 140 amino acids |
| Associated Diseases | Diamond-Blackfan Anemia, Alzheimer's Disease, Parkinson's Disease, Ribosomopathies |
RPL23 encodes ribosomal protein L23, a component of the 60S large ribosomal subunit. While traditionally known for its role in protein synthesis, RPL23 has gained attention for its extraribosomal functions, particularly in p53 activation following ribosomal stress. In neurons, RPL23 is essential for maintaining protein homeostasis, and its dysfunction has been implicated in Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions. Mutations in RPL23 cause Diamond-Blackfan anemia, demonstrating its critical role in hematopoiesis and cellular proliferation .
¶ Gene Structure and Expression
- Chromosomal location: 17q21.31
- Genomic size: ~4.5 kb
- Exon count: 5 exons
- Protein: 140 amino acids, ~14.9 kDa
RPL23 belongs to the ribosomal protein L23 family:
- Paralogs: RPL23A (highly similar, likely from gene duplication)
- Orthologs: Conserved across eukaryotes
- Pseudogenes: RPL23P1 (processed pseudogene)
RPL23 exhibits ubiquitous expression:
- Brain: High expression in cortex, hippocampus, cerebellum
- Bone marrow: High expression in hematopoietic cells
- Liver: Moderate expression
- Kidney: Moderate expression
- Heart: Low-moderate expression
RPL23 has dual localization:
- Ribosomal: Incorporated into 60S ribosomal subunit
- Nuclear: Can localize to nucleolus and nucleus
- Cytoplasmic: Present in cytosol during stress
¶ Protein Structure and Function
RPL23 contains characteristic ribosomal protein domains:
| Domain |
Position |
Function |
| N-terminal domain |
1-50 aa |
rRNA binding, ribosome assembly |
| Central domain |
51-100 aa |
Interprotein interactions |
| C-terminal domain |
101-140 aa |
MDM2 binding, p53 activation |
flowchart TD
A["RPL23 Protein"] --> B["Ribosome Assembly"]
B --> C["60S Subunit Formation"]
B --> D["rRNA Binding"]
C --> E["Polysome Formation"]
E --> F["Protein Synthesis"]
F --> G["Cellular Protein Homeostasis"]
A --> H["Extraribosomal Function"]
H --> I["MDM2 Binding"]
I --> J["p53 Activation"]
J --> K["Cell Cycle Arrest"]
J --> L["Apoptosis"]
style A fill:#e1f5fe
style G fill:#c8e6c9
style L fill:#ffcdd2
Beyond translation, RPL23 has important regulatory roles:
- p53 activation: Binds MDM2 under ribosomal stress
- Cell cycle regulation: Modulates G1/S transition
- Apoptosis: Promotes apoptosis when ribosomal integrity compromised
- DNA repair: Involved in DNA damage response
RPL23 contributes to several translation steps:
- Initiation: Part of 60S joining to 40S initiation complex
- Elongation: Facilitates tRNA translocation
- Termination: Involved in release factor recognition
- Quality control: Monitors translation fidelity
In neurons, protein synthesis is critical for:
- Synaptic plasticity: Local translation at synapses
- Axonal growth: Protein synthesis in growth cones
- Memory formation: Translation-dependent LTP/LTD
- Neurorepair: Response to injury
RPL23 alterations contribute to AD pathogenesis :
Ribosomal dysfunction:
- Global translation reduction in AD brain
- RPL23 levels altered in vulnerable regions
- Correlates with cognitive decline
Mechanistic links:
- Amyloid-β affects ribosomal function
- Tau pathology disrupts translation machinery
- RPL23 may affect amyloid processing
In PD, RPL23 plays several roles :
- Protein homeostasis: Disrupted RPL23 affects proteostasis
- Stress granules: RPL23 in stress granule formation
- Alpha-synuclein: Interaction with aggregation pathways
- Mitochondrial function: Links to PD pathology
RPL23 is central to ribosomal stress signaling :
- Ribosomal perturbation: Leads to RPL23 nucleolar release
- MDM2 inhibition: Free RPL23 binds and inhibits MDM2
- p53 stabilization: Accumulation leads to cell cycle arrest/apoptosis
- Neurodegeneration: Chronic stress leads to neuronal loss
RPL23 mutations cause DBA, a ribosomopathy characterized by:
- Pure red cell aplasia: Impaired erythropoiesis
- Growth retardation: Developmental delays
- Physical anomalies: Variable congenital features
- Cancer risk: Increased malignancy risk
| Defect |
Consequence |
| Haploinsufficiency |
Reduced RPL23 protein |
| Ribosome biogenesis defect |
Impaired 60S assembly |
| p53 activation |
Cell cycle arrest |
| Erythroid precursor death |
Anemia |
- Corticosteroids: First-line treatment
- Lenalidomide: Effective in some patients
- Gene therapy: Potential future approach
| Approach |
Mechanism |
Status |
| Ribosome modulators |
Enhance translation |
Research |
| p53 pathway modulators |
Fine-tune stress response |
Preclinical |
| Protein homeostasis enhancers |
Restore proteostasis |
Discovery |
| Small molecule stabilizers |
Stabilize ribosomal function |
Research |
- Alzheimer's disease: Enhance neuronal protein synthesis
- Parkinson's disease: Modulate stress granule dynamics
- Ribosomopathies: Correct ribosomal function
- Aging: Maintain protein homeostasis
- AD brain: Reduced RPL23 expression
- PD brain: Altered RPL23 levels in substantia nigra
- Aging: Gradual decline in ribosomal function
- Cancer: Often upregulated (pro-proliferative)
RPL23 interactions with pathological proteins:
- Tau: Found in some tau aggregate preparations
- TDP-43: Detected in some ALS inclusions
- Alpha-synuclein: May interact in PD
- RPL23 knockout mice: Embryonic lethal
- Heterozygous mice: Phenotypes similar to DBA
- Knock-in models: Specific human mutations
- Zebrafish: Developmental studies