Mitochondrial ribosome small subunit (28S subunit)

The mitochondrial ribosome small subunit (28S) is a specialized ribonucleoprotein complex essential for the translation of the 13 polypeptides encoded by mitochondrial DNA (mtDNA) (Greber & Ban, 2016, Annual Review of Biochemistry). These proteins are core components of the oxidative phosphorylation (OXPHOS) machinery, making the small subunit indispensable for cellular energy production (Amunts et al., 2015, Science). Structurally, it is composed of the 12S ribosomal RNA and approximately 30 mitoribosomal proteins (MRPS) (UniProt, 2024). Due to its evolutionary descent from alphaproteobacteria, the 28S subunit shares significant structural homology with the bacterial 30S ribosome, which explains the off-target toxicity of certain antibiotics like tetracyclines and aminoglycosides (Guan et al., 2000, Human Molecular Genetics). In clinical research, this subunit is being investigated as a therapeutic target in oncology, as many cancer cells rely on upregulated mitochondrial biogenesis for survival and metastasis (Lamb et al., 2015, Oncotarget). Mutations in the genes encoding the 28S subunit components are associated with severe clinical phenotypes, including Leigh syndrome and sensorineural hearing loss (PubMed, 2022).

Other names

28S ribosomal subunitMitoribosomal small subunitSSUSmall mitoribosomal subunit12S rRNA-protein complex

Inhibition of mitochondrial protein synthesis by binding to the 28S subunit, which interferes with the binding of aminoacyl-tRNA to the ribosomal A-site or induces translational misreading (PubMed, 2023).