MRPL3 Gene - Mitochondrial Ribosomal Protein L3 | Function, Mutations & Disease

MRPL3 encodes a 39S subunit protein of the mitochondrial ribosome. This nuclear-encoded ribosomal protein is imported into the mitochondria and assembles into the large ribosomal subunit (mt-LSU). MRPL3 is essential for mitochondrial translation, enabling the synthesis of 13 subunits of the oxidative phosphorylation (OXPHOS) system encoded by mitochondrial DNA. Mutations in MRPL3 cause combined oxidative phosphorylation deficiency 9 (COXPD9), a severe multisystem disorder.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Mitochondrial translation (Reactome: R-HSA-5368287)

• Oxidative phosphorylation (KEGG: hsa00190)

• Organelle biogenesis and maintenance (Reactome: R-HSA-1852241)

MRPL3 is a 39S mitochondrial ribosomal protein (L3) that forms part of the peptidyltransferase center of the large ribosomal subunit. It is synthesized in the cytosol and imported into the mitochondrial matrix. The protein contains a conserved RNA-binding domain and is critical for the accurate decoding of mitochondrial mRNAs. Defects in MRPL3 lead to impaired assembly of the mitochondrial ribosome and a global reduction in the translation of mtDNA-encoded OXPHOS subunits, resulting in combined oxidative phosphorylation deficiency.