TP53BP2 and lung cancer: To confirm that the identified PRR region of NS5A is required to mediate ASPP2-NS5A binding in cells and that this interaction is not specific to hepatocytes nor dependent on p53, the originally identified ASPP2 binding partner, we co-transfected an myc-tagged ASPP2 with HA-tagged wild-type full-length NS5A or the PRR-deleted derivative NS5A-ΔPRR into the p53 null human lung cancer cell line H1299.