RPL13A — Ribosomal Protein L13A
Overview
<table class="infobox infobox-gene">
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<th class="infobox-header" colspan="2">RPL13A — Ribosomal Protein L13A</th>
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<td class="label">:---</td>
<td>:---</td>
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<td class="label">Symbol</td>
<td>RPL13A</td>
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<td class="label">Name</td>
<td>Ribosomal Protein L13A</td>
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<td class="label">Chromosome</td>
<td>19q13.3</td>
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<td class="label">NCBI Gene ID</td>
<td>6145</td>
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<td class="label">UniProt ID</td>
<td>P32969</td>
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<td class="label">Ensembl ID</td>
<td>ENSG00000067533</td>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2 edges</a></td>
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RPL13A (Ribosomal Protein L13A) encodes a component of the large (60S) ribosomal subunit. Ribosomal proteins like RPL13A are essential for protein synthesis and have been increasingly recognized for their roles in regulating gene expression beyond canonical translation, including involvement in neurodevelopment and neurodegeneration.
Normal Function
Ribosomal Component
RPL13A is a member of the ribosomal protein L13P family and constitutes an integral component of the 60S large ribosomal subunit. The ribosome is the cellular machinery responsible for protein synthesis (translation), reading mRNA sequences and assembling amino acids into polypeptide chains. The 60S subunit performs the peptidyl transferase activity, catalyzing the formation of peptide bonds between amino acids during translation elongation.
As part of the large ribosomal subunit, RPL13A contributes to the structural integrity of the ribosome and participates in binding of translation factors. Ribosomal proteins are highly conserved across species, reflecting their fundamental importance in cellular physiology.
GAIT Complex Function
Beyond its structural role in the ribosome, RPL13A has a distinct function in the GAIT complex (IFN-γ-activated inhibitor of translation), a heterotetrameric protein complex that mediates interferon-γ (IFN-γ)-dependent translational repression of specific mRNAs.
The GAIT complex consists of four proteins:
RPL13A — the ribosomal anchor component
GLTCR1 (glycosylation-related tumor suppressor 1)
PCBP2 [poly(rC)-binding protein 2]
EPRS (glutamyl-prolyl-tRNA synthetase)RPL13A serves as the ribosomal docking site for the GAIT complex, tethering the complex to the ribosome. When activated by IFN-γ signaling, the GAIT complex binds to specific 3' UTR elements in target mRNAs, represses their translation, and plays a critical role in resolving inflammation by controlling the expression of inflammatory mediators.
Expression Pattern
RPL13A is ubiquitously expressed in all tissues, with high expression in tissues with active protein synthesis, including:
- Liver (hepatocytes)
- Skeletal muscle
- Brain (neurons and glia)
- Placenta
In the brain, RPL13A is expressed in both neurons and glial cells, consistent with its fundamental role in cellular protein synthesis. The protein is localized primarily in the cytoplasm, associated with ribosomes in the rough endoplasmic reticulum (RER) in protein-secreting cells.
Disease Associations
Ribosome and Translational Control in Neurodegeneration
The ribosomal apparatus has emerged as a critical player in neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). Multiple mechanisms link ribosomal dysfunction to neurodegeneration:
1. Translational Dysregulation in AD
In Alzheimer's disease, global protein synthesis is often dysregulated. Key observations include:
- Altered phosphorylation of ribosomal protein S6 (RPS6) in AD brains
- Reduced translation efficiency in hippocampal neurons
- Dysregulation of eukaryotic initiation factors (eIFs)
- Ribosome quality control failure leading to accumulation of defective ribosomal products (DRiPs)
RPL13A, as part of the translational machinery, is affected by these broader patterns of dysregulation. The GAIT complex function is particularly relevant given the inflammatory component of AD pathophysiology.
2. Ribosomal Stress in PD
Parkinson's disease pathology involves:
- Mitochondrial dysfunction leading to oxidative stress
- Alpha-synuclein aggregation
- Lysosomal dysfunction
Ribosomal biogenesis stress—where the cell's capacity to produce functional ribosomes is compromised—has been implicated in PD. Mutations in genes involved in rib biogenesis (e.g.,
GBA,
ATP13A2,
RPL5) are associated with PD risk. While RPL13A itself is not a PD risk gene, ribosomal stress contributes to the broader pathogenic cascade.
3. Ribosomal Protein L13 in Other Neurodegenerative Conditions
- Amyotrophic Lateral Sclerosis (ALS): Ribosomal RNA (rRNA) modifications are altered in ALS, affecting ribosome function
- Frontotemporal Dementia (FTD): Translational dysregulation is a feature of FTD pathology
- Huntington's Disease: Mutant huntingtin protein impairs ribosomal translation
Cancer Associations
Altered RPL13A expression has been reported in various cancers:
- Overexpression in certain lymphomas
- Potential role in tumor proliferation
- May serve as a prognostic marker in some contexts
However, the relationship between RPL13A and cancer is less direct than its role in neurodegeneration.
Molecular Mechanisms
Ribosome Biogenesis
Ribosome biogenesis is one of the most energy-intensive cellular processes, requiring:
- Transcription of rRNA genes by RNA polymerase I
- Transcription of ribosomal protein mRNAs by RNA polymerase II
- Assembly of ribosomal proteins with rRNAs in the nucleolus
- Transport of pre-60S subunits to the cytoplasm
RPL13A is synthesized in the cytoplasm and incorporated into pre-60S subunits during assembly. The process is regulated by:
- c-Myc (master regulator of ribosome biogenesis)
- mTOR signaling
- p53 (ribosomal stress sensor)
The GAIT Pathway in Neuroinflammation
The GAIT complex represents a specialized regulatory mechanism:
Activation: IFN-γ signaling activates EPRS, which becomes phosphorylated
Complex Assembly: Phosphorylated EPRS recruits GLTCR1, PCBP2, and RPL13A
Target Recognition: The complex binds GAIT elements in 3' UTRs of target mRNAs
Translation Repression: The complex blocks translation initiation or elongation
Resolution: This represses inflammatory gene expression to resolve immune responsesIn the brain, chronic neuroinflammation is a hallmark of AD and PD. The GAIT pathway may contribute to dysregulated inflammatory responses in neurodegeneration.
Mermaid Diagram: RPL13A Functions
Mermaid diagram (expand to render)
Therapeutic Implications
Targeting Translational Dysregulation
Therapeutic strategies targeting ribosomal function in neurodegeneration include:
mTOR inhibitors (e.g., rapamycin): Reduce translational burden, activate autophagy
Small molecule stabilizers: Enhance ribosomal assembly/f function
GAIT pathway modulators: Could fine-tune inflammatory responsesRibosome-Targeting Compounds
- Anisomycin: Protein synthesis inhibitor affecting the 60S subunit
- Puromycin: Causes premature chain termination
- Cycloheximide: Blocks translocation on the 60S subunit
These compounds have research but not therapeutic applications due to toxicity.
Key Research Findings
RPL13A in the GAIT complex: The ribosomal protein serves as an anchor for the IFN-γ-activated translational repressor complex, linking inflammatory signaling to translational control.
Ribosomal stress in neurodegeneration: Studies show that ribosomal biogenesis is impaired in AD and PD brains, with downstream effects on protein homeostasis.
Ribosomal protein mutations: While RPL13A mutations are not classically associated with neurodegeneration, mutations in other ribosomal proteins (RPL5, RPS14) cause Diamond-Blackfan anemia and predispose to cancer.
DRiPs and protein aggregation: Defective ribosomal products may contribute to proteotoxic stress in neurodegeneration.See Also
- [Ribosome Biogenesis](/mechanisms/ribosome-biogenesis)
- [Protein Synthesis](/mechanisms/protein-synthesis)
- [Proteostasis](/mechanisms/proteostasis)
- [Neuroinflammation](/mechanisms/neuroinflammation)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
External Links
- [NCBI Gene: RPL13A](https://www.ncbi.nlm.nih.gov/gene/6145)
- [UniProt: P32969](https://www.uniprot.org/uniprot/P32969)
- [Ensembl: ENSG00000067533](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000067533)
References
[RPL13A Gene - NCBI Gene Database](https://www.ncbi.nlm.nih.gov/gene/6145)
[RPL13A - UniProt](https://www.uniprot.org/uniprot/P32969)
[The GAIT complex: translational control in immune response (PubMed)](https://pubmed.ncbi.nlm.nih.gov/19779208/)
[Ribosomal biogenesis stress in neurodegeneration (PubMed)](https://pubmed.ncbi.nlm.nih.gov/34293125/)
[Dysregulated translation in Alzheimer's disease (PubMed)](https://pubmed.ncbi.nlm.nih.gov/33264425/)
[Proteostasis failure in neurodegenerative disease (PubMed)](https://pubmed.ncbi.nlm.nih.gov/25481467/)
[c-Myc regulation of ribosome biogenesis (PubMed)](https://pubmed.ncbi.nlm.nih.gov/22751934/)
[p53 as a ribosomal stress sensor (PubMed)](https://pubmed.ncbi.nlm.nih.gov/15635547/)
[GAIT complex-mediated translational control (PubMed)](https://pubmed.ncbi.nlm.nih.govPMC2585936/)
[Ribosomal proteins in cancer and disease (PubMed)](https://pubmed.ncbi.nlm.nih.gov/25212986/)