Together with recent data from other laboratories, they extend the view that Siz/PIAS proteins can function as SUMO ligases in yeast and mammals (7C9, 25). on glutathione-Sepharose 4B beads (Amersham Pharmacia) according to the manufacturer’s protocol. MBP-Ubc9 was purified on an amylose resin (New England Biolabs) according to the manufacturer’s protocol. The heterodimeric E1 was […]