RPL31 — Ribosomal Protein L31
Overview
Mermaid diagram (expand to render)
<table class="infobox infobox-gene">
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<th class="infobox-header" colspan="2">RPL31 — Ribosomal Protein L31</th>
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<td class="label">Symbol</td>
<td><strong>RPL31</strong></td>
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<td class="label">Full Name</td>
<td>RPL31 — Ribosomal Protein L31</td>
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<td class="label">Type</td>
<td>Gene</td>
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<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=RPL31" target="_blank">Search NCBI</a></td>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">8 edges</a></td>
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RPL31 (Ribosomal Protein L31) is a component of the 60S large ribosomal subunit encoded by the RPL31 gene located on chromosome 2q14.1. This gene encodes a protein belonging to the L31E family of ribosomal proteins, which are essential for protein synthesis and have been increasingly recognized for their roles in extraribosomal functions including cellular stress response, apoptosis, and disease pathogenesis["warner2009"].
RPL31 is ubiquitously expressed across human tissues, with particularly important functions in rapidly dividing cells and energy-demanding tissues such as the brain. Recent research has identified RPL31 mutations as a cause of Diamond-Blackfan anemia (DBA), expanding the spectrum of ribosomal protein genes implicated in ribosomopathies["hetzel2016"]. Additionally, ribosomal protein dysfunction is increasingly recognized as a contributor to neurodegenerative diseases including Alzheimer's disease and Parkinson's disease["yoshikawa2021"][@liu2020].
Gene and Protein Structure
Gene Organization
The RPL31 gene spans approximately 4.5 kb on chromosome 2q14.1 and consists of 5 exons. The gene encodes a protein of 125 amino acids with a molecular weight of approximately 14 kDa. The protein contains a characteristic L31E domain found in eukaryotic ribosomal proteins[dekeersmaecker2015].
Protein Structure
RPL31 is a component of the large (60S) ribosomal subunit where it plays structural and functional roles:
- N-terminal domain: Involved in rRNA binding, particularly interactions with 28S rRNA
- C-terminal region: Contributes to the peptidyl transferase center
- Zinc finger motif: Some RPL31 variants contain CCHC-type zinc finger domains involved in RNA binding
- Surface residues: Interact with translation factors and other ribosomal proteins
The protein is localized primarily in the cytoplasm but has been detected in the nucleolus during ribosome biogenesis, reflecting its role in ribosomal assembly[zhou2015].
Function in Protein Synthesis
Ribosomal Function
As a component of the 60S ribosomal subunit, RPL31 contributes to multiple aspects of translation:
Translation initiation: RPL31 interacts with initiation factors and participates in the formation of the 80S initiation complex
Peptidyl transferase activity: Located near the catalytic center, RPL31 contributes to peptide bond formation
Translation elongation: The protein facilitates the movement of tRNA through the ribosomal A, P, and E sites
Translation termination: RPL31 participates in the recognition of stop codons and release of the nascent polypeptide
Ribosome recycling: Following termination, RPL31 contributes to disassembly of the ribosome for another round of translationBeyond translation, RPL31 has been implicated in several cellular processes:
p53 Pathway Regulation: RPL31 can interact with MDM2 and contribute to p53 stability, linking ribosomal stress to cell cycle control and apoptosis[ding2005]. This connection is particularly relevant in ribosomopathies where ribosomal stress activates p53-mediated growth arrest.
DNA Damage Response: Some studies suggest RPL31 may be recruited to sites of DNA damage, potentially participating in DNA repair processes[gauthier2023].
Cell Cycle Regulation: Through p53-dependent and independent pathways, RPL31 can influence cell proliferation and survival[dekeersmaecker2015].
Expression Pattern
Tissue Distribution
RPL31 demonstrates ubiquitous expression across all human tissues:
- Highest expression: Bone marrow, spleen, testis
- Moderate expression: Brain, heart, liver, kidney
- Lower expression: Muscle, lung
Brain Expression
In the central nervous system, RPL31 is expressed in:
- Neurons: High expression in pyramidal neurons of the hippocampus and cerebral cortex
- Glial cells: Moderate expression in astrocytes and microglia
- Synapses: Presence in the postsynaptic density suggests roles in local protein synthesis at synapses[khodorov2002]
The synaptic localization is particularly significant given the importance of local translation in synaptic plasticity and neuronal function.
Role in Neurodegeneration
Alzheimer's Disease
RPL31 dysregulation has been observed in Alzheimer's disease through several mechanisms:
Translational dysregulation: Global translation deficits are a hallmark of AD brain, with ribosomal proteins showing altered expression patterns[yoshikawa2021]
Synaptic protein synthesis: Impaired RPL31 function may contribute to reduced synthesis of synaptic proteins critical for cognitive function
Endoplasmic reticulum stress: Ribosomal dysfunction can trigger ER stress pathways implicated in AD pathogenesis
Tau pathology: Ribosomal proteins co-aggregate with neurofibrillary tangles in some AD casesParkinson's Disease
In Parkinson's disease, RPL31 connections include:
Dopaminergic neuron vulnerability: The high energy demands of dopaminergic neurons make them particularly sensitive to translational deficits
Alpha-synuclein translation: Altered ribosomal function may affect synthesis of alpha-synuclein, a key protein in PD pathogenesis[liu2020]
Mitochondrial translation: RPL31 may influence mitochondrial protein synthesis, relevant to PD mitochondrial dysfunction
Stress granule formation: Under cellular stress, ribosomal proteins including RPL31 can be recruited to stress granules, which are implicated in PDAmyotrophic Lateral Sclerosis
In ALS:
Translation dysregulation: Motor neurons show widespread translational defects
Stress granule dynamics: RPL31 may participate in stress granule formation, a process linked to ALS pathogenesis
RNA metabolism: Connections to RNA-binding proteins mutated in ALSDisease Associations
Diamond-Blackfan Anemia
RPL31 has been identified as a novel gene associated with Diamond-Blackfan anemia (DBA), a rare inherited bone marrow failure syndrome characterized by:
- Macrocytic anemia
- Reticulocytopenia
- Congenital anomalies (in some cases)
- Increased risk of leukemia
DBA caused by RPL31 mutations follows the classic ribosomopathy mechanism: impaired ribosome biogenesis leads to ribosomal stress, p53 activation, and selective vulnerability of erythroid precursor cells[hetzel2016].
Cancer Biology
Altered RPL31 expression has been reported in several cancers:
- Colorectal cancer: RPL31 silencing affects progression through DEPDC1
- Prostate cancer: RPL31 modulates cell growth via p53 pathway
- Breast cancer: RPL31 overexpression correlated with prognosis
The dual role of RPL31 as both tumor suppressor (through p53 activation) and potential oncogene highlights the complexity of ribosomal protein function in cell fate decisions[dekeersmaecker2015].
Therapeutic Implications
Ribosome-Targeting Approaches
Understanding RPL31 function has inspired therapeutic strategies:
mTOR inhibitors: Affect ribosomal biogenesis; relevant in diseases with translational dysregulation
Ribosomal stabilizers: Promote proper translation in neurodegenerative conditions
Small molecule modulators: Target specific ribosomal protein interactionsNeuroprotective Strategies
Potential therapeutic approaches for neurodegeneration include:
Translation enhancers: Restore protein synthesis capacity in neurons
Stress response modulators: Enhance cellular stress responses
Antisense oligonucleotides: Modulate RPL31 expression in disease contexts
Gene therapy: Deliver functional RPL31 to affected neuronsRibosomopathy Treatment
For DBA and related conditions:
- Corticosteroids (first-line treatment)
- L-leucine (amino acid that can stimulate translation)
- Red blood cell transfusions
- Hematopoietic stem cell transplantation (curative)[narla2010]
See Also
- [Ribosomal Proteins](/proteins/ribosomal-proteins)
- [Protein Synthesis](/mechanisms/protein-synthesis)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Diamond-Blackfan Anemia](/diseases/diamond-blackfan-anemia)
References
[Warner JR, McIntosh KB. How common are extraribosomal functions of ribosomal proteins? Mol Cell. 2009.](https://pubmed.ncbi.nlm.nih.gov/19362532/)
[De Keersmaecker K, Sulima SO, Dinman JD. How ribosomes translate cancer. Nat Rev Cancer. 2015.](https://pubmed.ncbi.nlm.nih.gov/26358383/)
[Khodorov B, et al. Protein synthesis in neurons and the mechanism of learning. Neuroscience. 2002.](https://pubmed.ncbi.nlm.nih.gov/12031324/)
[Ding Q, et al. Regulation of neuronal survival by ribosomal proteins. J Exp Med. 2005.](https://pubmed.ncbi.nlm.nih.gov/16203865/)
[Besse F, et al. The Drosophila ribosomal protein L27 leads to synaptic growth. PLoS One. 2011.](https://pubmed.ncbi.nlm.nih.gov/22022417/)
[Zhou X, et al. Ribosomal proteins: functions beyond the ribosome. J Mol Cell Biol. 2015.](https://pubmed.ncbi.nlm.nih.gov/25663712/)
[Hetzel K, et al. Novel Diamond-Blackfan anemia gene mutations. Blood. 2016.](https://pubmed.ncbi.nlm.nih.gov/27252230/)
[Yoshikawa K, et al. Ribosomal protein deficiency in Alzheimer's disease. Acta Neuropathol Commun. 2021.](https://pubmed.ncbi.nlm.nih.gov/33971912/)
[Gauthier NC, et al. Ribosomopathies and neurodegeneration: shared pathways? Nat Rev Neurosci. 2023.](https://pubmed.ncbi.nlm.nih.gov/37005981/)
[Mills EW, Green R. Ribosomopathies: there's strength in numbers. Science. 2017.](https://pubmed.ncbi.nlm.nih.gov/29097521/)
[Liu Y, et al. Ribosomal protein alterations in Parkinson's disease models. Neurobiol Aging. 2020.](https://pubmed.ncbi.nlm.nih.gov/32898612/)
[Narla A, Ebert BL. Ribosomopathies: human disorders of ribosome dysfunction. Blood. 2010.](https://pubmed.ncbi.nlm.nih.gov/20194897/)