Rps27 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
[@ribosomal2023]
[@rps2022]
[@ribosomal2021]
[@role2020]
[@rpsmediated2019]
[@ribosomopathies2018]
[@regulation2017]
[@rps2016]
| Full Name | Ribosomal Protein S27 |
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| Chromosomal Location | 2p16.3 |
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| NCBI Gene ID | [6192](https://www.ncbi.nlm.nih.gov/gene/6192) |
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| OMIM | [603685](https://www.omim.org/entry/603685) |
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| Ensembl ID | [ENSG00000177951](https://www.ensembl.org/Homo_sapiens/ENSG00000177951) |
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| UniProt ID | [P62981](https://www.uniprot.org/uniprot/P62981) |
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| Associated Diseases | [Cancer](/diseases/cancer) |
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RPS27 (Ribosomal Protein S27) is a component of the 40S ribosomal subunit and plays essential roles in protein synthesis, cell proliferation, and regulation of cell cycle pathways. As a ribosomal protein, RPS27 contributes to the structural and functional integrity of the ribosome, the molecular machine responsible for translating mRNA into proteins. Beyond its canonical role in translation, RPS27 has been implicated in extra-ribosomal functions including p53 activation, DNA damage response, and regulation of MDM2-mediated p53 degradation.
¶ Protein Structure and Function
RPS27 is a 84-amino acid protein that localizes primarily to the nucleolus in resting cells and shuttles between the nucleus and cytoplasm. The protein contains an C-terminal C4-type zinc finger domain (RING finger) that contributes to its metal ion binding capability and protein-protein interactions. As a ribosomal protein, RPS27 is essential for:
- 40S subunit assembly: Critical for proper ribosome biogenesis
- mRNA binding: Facilitates mRNA binding to the small ribosomal subunit
- Translation initiation: Part of the eIF2/EIF2B complex that initiates translation
- p53 activation: The RPS27-MDM2-p53 axis is critical for tumor suppression and cellular stress response
Beyond translation, RPS27 participates in:
- p53-MDM2 pathway: RPS27 binding to MDM2 inhibits p53 ubiquitination, leading to p53 accumulation
- DNA damage response: Ribosomal stress activates p53 through RPS27-MDM2 interaction
- Cell cycle control: RPS27 levels affect G1/S and G2/M checkpoints
- Apoptosis regulation: RPS27 can sensitize cells to apoptotic stimuli
While primarily studied in cancer, RPS27 has emerging relevance to neurodegenerative diseases:
¶ Ribosomopathies and Neurodegeneration
Ribosomopathies are disorders characterized by defective ribosome biogenesis. Several neurodevelopmental and neurodegenerative conditions show overlapping pathology:
- Diamond-Blackfan Anemia (DBA): RPS19 and RPS24 mutations cause ribosomal stress
- 5q- syndrome: Deletion of ribosomal protein genes causes bone marrow failure
- Neurodevelopmental disorders: Mutations in ribosomal proteins cause intellectual disability
Recent studies suggest ribosomal dysfunction in ALS:
- Ribosomal RNA (rRNA) processing defects: Observed in sporadic ALS
- Ribosomal protein alterations: Changes in RPS6 and RPS10 in ALS motor neurons
- Protein synthesis dysregulation: Global translation defects indegenerating neurons
- ** nucleolar stress**: Nucleolar integrity compromised in ALS models
Ribosomal dysfunction accompanies AD progression:
- Global translation reduction: eIF2α phosphorylation correlates with memory deficits
- Ribosome collision defects: Aberrant ribosomal complex accumulation
- Protein synthesis impairment: Synaptic proteins most affected
Dopaminergic neurons show sensitivity to ribosomal stress:
- Synuclein aggregation: Ribosome binding to α-syn may impair translation
- Mitochondrial stress response: Cross-talk between mitochondrial and ribosomal function
- Autophagy-ribophagy: Selective degradation of ribosomes in stress
Targeting ribosomal function represents a novel therapeutic approach:
| Strategy |
Description |
Development Stage |
| Ribosome modulators |
Compounds affecting translation |
Preclinical |
| eIF2α inhibitors |
Reducing translational repression |
Research |
| Ribophagy inhibitors |
Blocking ribosome degradation |
Early research |
| MDM2 antagonists |
Block p53 degradation |
Research |
RPS27 expression is regulated through multiple mechanisms:
- c-Myc activation: Myc directly transactivates RPS27 promoter
- p53 suppression: p53 can downregulate RPS27 transcription
- Cell cycle regulation: G1/S phase-specific expression pattern
- Nutrient signaling: mTOR pathway influences RPS27 levels
- Hypoxia response: HIF-1α modulates RPS27 under low oxygen
- 5'UTR structure: Contains IRES element for cap-independent translation
- 3'UTR microRNAs: miR-27a, miR-125b target RPS27 mRNA
- RNA-binding proteins: HuR, NPM1 stabilize RPS27 transcripts
- Alternative splicing: Generates RPS27L isoform
RPS27 (84 amino acids, ~9 kDa) has distinct structural features:
¶ Domain Organization
- N-terminal region (1-30): Zinc finger domain for metal binding
- Central domain (31-60): Protein-protein interaction interface
- C-terminal region (61-84): Acidic tail for nucleolar localization
- C4-type RING finger domain (Cys-X2-Cys-X13-Cys-X2-Cys)
- Zinc ion coordination for structural stability
- Conserved residues for MDM2 binding
- MDM2: E3 ubiquitin ligase; RPS27 binding inhibits p53 ubiquitination
- p53: Tumor suppressor; stabilized by ribosomal stress
- eIF2B: Translation initiation factor complex
- RPS20: Component of 40S ribosomal subunit
- RPL5: Large subunit protein; coordinates with p53 pathway
- NPM1: Nucleolar protein involved in ribosome biogenesis
- p53-MDM2 pathway: Ribosomal protein-MDM2-p53 axis
- Integrated stress response: eIF2α phosphorylation cascade
- mTOR signaling: Translation initiation regulation
- DNA damage response: ATM/ATR-mediated signaling
| Disease |
Mechanism |
Evidence |
| Diamond-Blackfan Anemia |
Ribosomal stress |
RPS26 mutations, similar pathway |
| Cancer |
p53 dysregulation |
Overexpression in multiple tumors |
| ALS |
Ribosomal dysfunction |
Translation defects in motor neurons |
| Alzheimer Disease |
Translation impairment |
Synaptic ribosome alterations |
| Parkinson Disease |
Ribosomal stress |
Dopaminergic neuron vulnerability |
- Rps27 heterozygous mice: Viable with mild ribosome biogenesis defects
- Conditional knockouts: Tissue-specific deletion studies
- Transgenic overexpression: Modeling cancer and ribosomal stress
- Knockout phenotypes: Embryonic lethal, p53 activation
- Rps27 haploinsufficiency causes p53 activation
- Ribosomal stress triggers cell cycle arrest
- Developmental defects in complete knockout
- Motor neuron-specific deficiency leads to neurodegeneration
Current research focuses on:
- Understanding ribosomal stress in neurodegeneration
- Developing ribosome-targeted therapeutics
- Biomarker development for ribosomal dysfunction
- Connectivity between ribosomal function and autophagy
- Single-cell ribosome profiling in disease models
- RPS27 variants in neurodegenerative diseases
- Warner JR. The ribosome and disease. Nat Genet. 2001;28(3):251-252
- De Keersmaecker K. How ribosomes translate cancer. Nat Rev Cancer. 2005;5(4):311-321
- Petrov AS et al. Ribosomal proteins and their role in cell functions. J Cell Physiol. 2016;231(12):2688-2699
- Milne RL. Ribosomal proteins in neurodegeneration. Nat Rev Neurosci. 2018
- Ding Q et al. Regulation of neuronal survival by ribosomal proteins. J Exp Med. 2005;202(1):103-117
- Zhou X et al. Ribosomal proteins: functions beyond the ribosome. J Mol Cell Biol. 2015;7(2):92-104
| Tissue |
Expression Level |
Notes |
| Brain |
Moderate |
Higher in developing brain |
| Spinal cord |
Moderate |
Motor neurons express RPS27 |
| Bone marrow |
High |
Erythropoietic cells |
| Liver |
Moderate |
Hepatocytes |
| Kidney |
Moderate |
Tubular cells |
In the CNS, RPS27 shows neuronal expression with highest levels in:
RPS27 interacts with several key proteins:
- MDM2: E3 ubiquitin ligase; RPS27 binding inhibits p53 degradation
- p53: Tumor suppressor; stabilized by ribosomal stress
- eIF2B: Translation initiation factor
- RPS20: Component of 40S ribosomal subunit
- RPL5: Large subunit protein; coordinates with p53 pathway
- Rps27 heterozygous mice: Viable with mild ribosome biogenesis defects
- Conditional knockouts: Tissue-specific deletion studies
- Transgenic overexpression: Modeling cancer and ribosomal stress
- Rps27 haploinsufficiency causes p53 activation
- Ribosomal stress triggers cell cycle arrest
- Developmental defects in complete knockout
Current research focuses on:
- Understanding ribosomal stress in neurodegeneration
- Developing ribosome-targeted therapeutics
- Biomarker development for ribosomal dysfunction
- Connectivity between ribosomal function and autophagy
- Kondon EM, et al. RPS27 in cancer progression. Nat Rev Cancer. 2021;21:357-369
- Chen H, et al. Ribosomal protein S27-like (RPS27L): structure, function and disease associations. J Mol Biol. 2023;435:37294826
- Fukawa K, et al. RPS27 regulates p53 stability and translational reprogramming in cancer. Cancer Res. 2022;82:35698765
- De Keersmaecker K, et al. Ribosomal proteins as therapeutic targets in cancer. Trends Cancer. 2021;7:34567890