MTBP (IN2)

The p53 tumor-suppressor gene integrates numerous signals that control cell life and death. Several novel molecules involved in p53 network, including Chk2 , p53R2 (2), p53AIP1 (3), Noxa (4), PIDD (5), PID/MTA2 (6) and MTBP (7), were recently discovered. The transcriptional activity of p53 is modulated by posttranslational regulations of the p53 protein including stabilization and acetylation. P53 transcriptionally activates MDM2 gene then the translated MDM2 protein binds to p53 and promotes the degradation of p53 leading to lowering the concentration of p53 protein. MDM2 inhibits both p53 mediated G1 arrest and apoptosis. A recently discovered protein termed MTBP was found to bind to MDM2 and to inhibit the modulation effect of MDM2 on p53 (7). MTBP is expressed in a variety of normal tissues (7).