A putative nuclear function for mammalian Staufen.

In addition to its role in rRNA processing and ribosome assembly, the nucleolus plays a part in the assembly of non-ribosomal ribonucleoprotein particles (RNPs) that are destined for cytoplasmic RNA delivery. Recent evidence indicates that mammalian Staufen2, a brain-specific RNA-binding protein involved in RNA localization, can--at least transiently--enter the nucleolus. Therefore, the assembly of Staufen2 into transport-competent RNPs might occur in the nucleus before their export into the cytoplasm. This could provide new insights into the mechanisms of subcellular RNA localization.