FIG. 2.

Specific sumoylation of MEF2C and MEF2D. (A to C) In vivo sumoylation assays. Expression plasmids for the indicated proteins were transfected into HEK293 cells. Extracts were prepared in buffer S for immunoprecipitation on M2 agarose, and bound proteins were eluted with Flag peptide and analyzed by Western blotting (WB) with anti-HA (top) or anti-Flag (bottom) antibody. Like HA-SUMO2, HA-SUMO3 was also conjugated to MEF2D (data not shown). (D) Extracts from HEK293 cells expressing Flag-MEF2D or Flag-K439R were used for immunoprecipitation on M2 agarose. Bound proteins were eluted with Flag peptide and subjected to Western blotting analysis with anti-Flag (left) or anti-MEF2D (right) antibody.