FIGURE 5.

hnRNP K sumoylation is required for p53 transcriptional co-activation. A, HEK 293T cells were transfected with the indicated plasmids and then analyzed by Ni²⁺ affinity chromatography. B and C, Pc2 and HIPK2 regulate hnRNP sumoylation. HEK 293T cells were transfected with the indicated plasmids, and 48 h later they were treated with 1 μm doxorubicin (Dox) for 4 h. Then, HA-hnRNP K sumoylation was analyzed by Ni²⁺ affinity chromatography. D, cells were transfected with a plasmid carrying 16 tandem p53 binding sites upstream of the firefly luciferase coding sequence, together with HA-hnRNP K, Pc2, or HIPK2 and lysed 48 h later for luciferase activity measurement. E, cells were transfected with a plasmid carrying 16 tandem p53 binding sites upstream of the firefly luciferase coding sequence, together with HA-hnRNP K, Pc2 ΔSIM, or HIPK2 K221A and analyzed as in D. Data are represented as mean ± S.E., and p values of Student's t test are shown.