Tripartite motif-containing protein 29 (TRIM29, ATDC) was isolated as a candidate gene by its ability to complement the radiosensitivity defect of an ataxia-telangiectasia (AT) cell line. This putative transcription regulator belongs to the TRIM (tripartite motif) protein family that is characterized by highly conserved amino-terminal RING finger, B-box, and coiled-coil domains. The TRIM29 protein binds and sequesters cytosolic p53, repressing expression of p53 target genes including p21 and Noxa by preventing p53 from entering the nucleus. Expression of TRIM29 inhibits p53 function and results in increased cell proliferation. TRIM29 enhances tumor growth and metastasis in vivo and high TRIM29 levels are seen in most invasive pancreatic cancers. The oncogenic effect of TRIM29 appears to require β-catenin as expression of both proteins is elevated in pancreatic cancer cell lines and tissues .