or the knock-down of both variants resulted in enhanced p53 phosphorylation and stabilization (45). On the other hand, other clues suggest functional differences between the two variants. For example, whereas PPM1D605 expression is ubiquitous, PPM1D430 is highly expressed in the testis and in leukocytes. Furthermore, in MCF-7 cells, both variants localize to the nucleus, whereas in T47D cells, PPM1D605 localizes to the nucleus but PPM1D430 was found in the cytoplasm, the plasma membrane, and the nucleus (Figure 3). Given the differences in tissue expression patterns and subcellular localization, the two variants may exhibit functional differences, but this is currently unknown.
