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 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). Interacts with NR1D1, THRA, THRB, NCOR1 and NCOR2. EXOSC10 is required for nucleolar localization. Colocalizes with TSNAX in the nucleus. Kidney, heart, brain, spleen, lung, testis, liver and small intestine. Up-regulated during adipocyte and myogenic differentiation. Phosphorylated by PRKDC. Belongs to the C1D family.