This gene encodes a transcriptional co-activator that interacts with the acidic domain of Epstein-Barr virus nuclear antigen 2 (EBNA 2), a transcriptional activator that is required for B-lymphocyte transformation. Other transcription factors that interact with this protein are signal transducers and activators of transcription, STATs. This protein is also thought to be essential for normal cell growth. A similar protein in mammals and other organisms is a component of the RNA-induced silencing complex (RISC).