Targeting RNA for processing or destruction by the eukaryotic RNA exosome and its cofactors

The eukaryotic RNA exosome is an essential and conserved protein complex that can degrade or process RNA substrates in the 3'- to- 5' direction. Since its discovery nearly two decades ago, studies have focused on determining how the exosome, along with associated cofactors, achieves the demanding task of targeting particular RNAs for degradation and/or processing in both the nucleus and cytoplasm. In this review, we highlight recent advances that have illuminated roles for the RNA exosome and its cofactors in specific biological pathways, alongside studies that attempted to dissect these activities through structural and biochemical characterization of nuclear and cytoplasmic RNA exosome complexes.