Tyrosine phosphatase SHP-2 modulates the cell cycle regulator p27Kip1 in promyelocytic leukemia cells

Protein tyrosine phosphorylation controls a wide range of critical biological processes. Recently, we provided the first evidence that the level of tyrosine phosphorylation of the cell cycle regulator p27Kip1 plays a crucial role in its binding to cyclin dependent kinases and its subcellular localization. While Src and Bcr-Abl were shown to be responsible for tyrosine phosphorylation, no data are available on the dephosphorylation of p27Kip1 and the phosphatase involved. Considering the associated dephosphorylation as a pivotal event in the regulation of cell cycle proteins, we focused on the tyrosine phosphatas…