Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and play a crucial role in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) are composed of a small 28S subunit and a large 39S subunit, with an estimated protein to rRNA composition of 75% with contrasts with prokaryotic ribosomes, where this ratio is reversed. Another distinction between mammalian mitoribosomes and prokaryotic ribosomes is that the latter includes a 5S rRNA. The proteins that make up the mitoribosome vary significantly in sequence, and sometimes in biochemical properties across different species, which prevents easy recognition by sequence homology. This gene encodes a 39S subunit protein.
