P53 and PML: new partners in tumor suppression

Whether cells die, differentiate or senesce depends on specific molecular programs. Although the full cast of players in each of these processes has not been identified, regulatory roles for the tumor suppressors p53 and the promyelocytic leukemia protein - PML - appear to be essential. The extent of cross-talk between these factors, however, remains to be determined. Recently, new discoveries link p53 and PML by showing that the latter is required for the efficient onset of both p53-dependent apoptosis and cell senescence induced by the oncogenic form of the ras protein.