Fig. 2. In vitro modification by SUMO-1 and SUMO-2 of HDACs and HDAC-related proteins. ³⁵S-labelled in vitro translated HDAC1, HDAC3, HDAC6 and MITR were incubated in a sumoylation mix containing a fraction of HeLa cells providing the E1 activity together with recombinant Ubc9, in either the absence (MIX) or presence of recombinant SUMO-1 or SUMO-2. The positions of unmodified and modified substrate proteins are indicated.