FIGURE 4.

Plk1 phosphorylates PTEN in the C-tail region. A, schematic presentations show various deletion and mutation constructs of PTEN. B, full-length PTEN and various deletion counterparts were expressed and purified as GST fusion proteins. Purified proteins, along with purified GST, were incubated with Plk1 in the assay reaction containing [γ-³²P]ATP. After the reaction, the assay samples were fractionated by SDS-PAGE followed by autoradiography (lower panel). The same blot was also probed with the antibody to GST (upper panel). NS denotes a nonspecific band. C, full-length PTEN and various mutational counterparts in the C-tail domain as described in A were expressed and purified as GST fusion proteins. Purified proteins, along with purified GST, were incubated with Plk1 in the kinase reaction containing [γ-³²P]ATP. After the reaction, the assay samples were fractionated by SDS-PAGE followed by autoradiography (upper panel). The same blot was also stained with Coomassie Blue (lower panel). NS denotes a nonspecific band.