The Other Lives of Ribosomal Proteins

Cellular mRNAs are produced in the nucleus and exported to the cytoplasm through nuclear pore complexes (NPC) that are found in the nuclear membrane. The correctly processed mRNAs are exported in the form of messenger ribonucleoproteins (mRNPs). Since the NPC allows the passage of only one mRNA molecule at a time, export of large ribonucleoproteins (megaRNP) found in the nucleus cannot be transported through the NPC. However, a recent study has discovered an alternative export mechanism known as nuclear envelope budding, which allows megaRNP granules to be exported. This study particularly focuses on identifying ribosomal proteins (RPs) found within large RNA granules within the salivary gland, and neuromuscular junction (NMJ) of Drosophila melanogaster larvae. Although, RPs are known mainly for playing an essential role in ribosome assembly and protein translation that occurs in the cytoplasm, recent discoveries have shown that ribosomal proteins possess ribosome-independent functions, which are essential for a cell survival and proper animal development. This study finds that Rps3 is possibly localized within large RNA granules within NMJ of Drosophila larvae; however, the future in-depth studies are needed to verify this finding and identify the specific function of Rps3 in the megaRNP granules