Fig. 2

USP7 protein co-localizes and interacts with PLK1 protein. a Tandem affinity purification was performed using HEK293T cells stably expressing Flag-tagged PLK1. The major hits from mass spectrometry analysis are shown in the Table. b PLK1 protein interacts with USP7 protein. DU145 cells were lysed and immunoprecipitation and immunoblotting were performed using the indicated antibodies. c GST-pull-down assay of PLK1 using the indicated GST fusion proteins. USP7 protein was detected. d DU145 cells expressing PLK1-Flag were stained with anti-USP7 (red) and anti-Flag antibody (green). Cellular nuclei were labeled with DAPI. Scale bar, 10 μM. e Schematic diagram of PLK1 protein domains. f HEK293T cells were transfected with Flag-tagged plasmids expressing full length PLK1 or its truncated mutants as indicated. Cell lysates were immunoprecipitated with anti-Flag antibody, followed by immunoblotting with anti-USP7 antibody. g Purified recombinant proteins of GST, GST-PLK1(FL) and GST-PLK1(AA) were incubated with cell lysates in vitro as indicated, followed by immunoblotting with anti-USP7 antibody