MRPS23 Human
Description
Introduction to MRPS23 Human
MRPS23 (Mitochondrial Ribosomal Protein S23) is a nuclear-encoded component of the small subunit (28S) of human mitochondrial ribosomes. It plays a critical role in mitochondrial translation, a process essential for synthesizing 13 of the 90 proteins in the electron transport chain complexes. MRPS23 is encoded by the MRPS23 gene located on chromosome 17q22 .
2.1. Protein Structure
MRPS23 is a non-glycosylated polypeptide with a conserved proline residue at position 40 (p.P40), critical for its function . Recombinant MRPS23 produced in E. coli includes a His-tag for purification and retains structural integrity, as confirmed by SDS-PAGE (>85% purity) .
2.2. Role in Mitochondrial Translation
MRPS23 is integral to the mitoribosome’s small subunit, enabling translation of mitochondrial DNA-encoded proteins. Defects in this protein disrupt oxidative phosphorylation (OXPHOS), leading to metabolic and clinical abnormalities .
3.1. Genetic Variants and Disease Pathology
A pathogenic variant c.119C>T (p.P40L) in MRPS23 has been linked to autosomal recessive mitochondrial disorders. Key findings from studies on Hmong populations include:
3.2. Biochemical Defects
Patients with MRPS23 mutations exhibit combined deficiencies in respiratory chain complexes:
Oncological Implications
MRPS23 overexpression is associated with aggressive cancer phenotypes, particularly in hepatocellular carcinoma (HCC) and glioma.
4.1. Hepatocellular Carcinoma (HCC)
Knockdown of MRPS23 in HCC cell lines reduces proliferation and tumor growth in xenograft models .
4.2. Glioma
| Prognostic Factor | High MRPS23 | Low MRPS23 | p-value |
|---|---|---|---|
| WHO Grade IV | 125/348 (36%) | 43/348 (12%) | <0.001 |
| IDH Wild-Type | 161/348 (46%) | 85/348 (24%) | <0.001 |
| OS (5-year) | 18% | 35% | <0.001 |
MRPS23 knockdown in glioma cells inhibits survival and migration, highlighting its role in tumor progression .
5.1. Biomarker Utility
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MRPS23 expression correlates with poor prognosis in early-stage HCC and glioma, making it a candidate for stratifying patients .
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Nomograms incorporating MRPS23 levels improve survival predictions in glioma, as demonstrated in calibration curves for 1-, 3-, and 5-year outcomes .
5.2. Mechanistic Insights
Product Specs
Product Science Overview
Mitochondrial ribosomes, also known as mitoribosomes, are responsible for protein synthesis within the mitochondria. They consist of a small 28S subunit and a large 39S subunit. Unlike prokaryotic ribosomes, which have a higher rRNA to protein ratio, mitoribosomes have an estimated 75% protein to rRNA composition . This difference is significant because it highlights the unique evolutionary path of mitochondrial ribosomes compared to their prokaryotic counterparts.
The MRPS23 protein itself is composed of 190 amino acids and has a calculated molecular mass of approximately 21.8 kDa . It plays a crucial role in the assembly and function of the mitochondrial ribosome, contributing to the overall process of mitochondrial protein synthesis.
Mutations or deficiencies in the MRPS23 gene have been associated with certain mitochondrial disorders. Notably, Combined Oxidative Phosphorylation Deficiency 46 and Combined Oxidative Phosphorylation Deficiency 8 are linked to anomalies in this gene . These conditions can lead to severe metabolic dysfunctions due to impaired mitochondrial protein synthesis.
The proteins comprising the mitoribosome, including MRPS23, differ significantly in sequence and biochemical properties among different species . This variability prevents easy recognition by sequence homology and underscores the evolutionary divergence of mitochondrial ribosomes from their prokaryotic ancestors.
Research on MRPS23 and other mitochondrial ribosomal proteins is ongoing, with a focus on understanding their roles in mitochondrial function and their implications in various diseases. Recombinant forms of MRPS23 are used in research to study its structure, function, and interactions with other mitochondrial components.
