Participates in MYC-mediated cell transformation and apoptosis; induces anchorage-independent growth and clonogenicity in lymphoblastoid cells. Insufficient to induce tumorigenicity when overexpressed but contributes to MYC-mediated tumorigenesis. May play a role as transcriptional regulator (By similarity). Interacts with MYC (via C-terminus), YWHAE and YWHAZ. Predominantly nuclear with some expression also seen in the cytoplasm. Predominantly cytoplasmic when phosphorylated at Thr-163 (By similarity). Phosphorylation at Thr-163 promotes interaction with YWHAE and YWHAZ, dissociation from MYC and sequestration in the cytoplasm.