Mitochondrial Ribosomal Protein L2 (MRPL2) is a crucial component of the mitochondrial ribosome, specifically the large 39S subunit. This protein plays a significant role in mitochondrial protein synthesis, which is essential for the proper functioning of the mitochondria and, consequently, cellular energy production.
The MRPL2 gene is located on chromosome 6 and is encoded by nuclear DNA. It belongs to the EcoL2 ribosomal protein family . The gene undergoes alternative splicing, resulting in multiple transcript variants that encode distinct isoforms of the protein . Additionally, a pseudogene corresponding to MRPL2 is found on chromosome 12q .
Mitochondrial ribosomes, or mitoribosomes, are responsible for synthesizing proteins within the mitochondria. Unlike prokaryotic ribosomes, mitoribosomes have a higher protein-to-rRNA ratio, estimated at 75% protein to rRNA . This difference is significant because it highlights the unique composition and function of mitoribosomes compared to their prokaryotic counterparts.
MRPL2 is a structural constituent of the ribosome and is involved in RNA binding . It is essential for the assembly and stability of the 39S subunit, which, along with the small 28S subunit, forms the complete mitochondrial ribosome . The proper functioning of MRPL2 is vital for mitochondrial translation and, by extension, cellular respiration and energy production.
MRPL2 is ubiquitously expressed in various tissues, with cytoplasmic expression observed in all tissues . It is primarily localized to the mitochondria but is also found in the nucleoplasm . This widespread expression underscores the importance of MRPL2 in maintaining mitochondrial function across different cell types.
Mutations or dysregulation of MRPL2 can have significant implications for cellular function and health. For instance, diseases such as chronic gonococcal salpingitis have been associated with MRPL2 . Additionally, the protein’s involvement in mitochondrial translation links it to various mitochondrial disorders, which can manifest in a wide range of clinical symptoms due to the critical role of mitochondria in energy production.