Plays a role in the recruitment of the RNA exosome complex to pre-rRNA to mediate the 3'-5' end processing of the 5.8S rRNA; this function may include MPHOSPH6. Can activate PRKDC not only in the presence of linear DNA but also in the presence of supercoiled DNA. Can induce apoptosis in a p53/TP53 dependent manner. May regulate the TRAX/TSN complex formation. Potentiates transcriptional repression by NR1D1 and THRB (By similarity). Monomer and homodimer. Interacts with NR1D1, THRA, THRB, NCOR1 and NCOR2. Interacts with EXOSC10; the interaction probably mediates the association with the nuclear form of the RNA exosome. The homodimeric form interacts with TSNAX following gamma-radiation. Interacts with RAC3 (By similarity). EXOSC10 is required for nucleolar localization. Colocalizes with TSNAX in the nucleus. Phosphorylated by PRKDC. Belongs to the C1D family.