Activity-dependent SUMOylation of the brain-specific scaffolding protein GISP

► The brain-specific protein GISP interacts with the SUMO conjugating enzyme Ubc9. ► GISP is SUMOylated at multiple sites. ► GISP SUMOylation is decreased by viral expression of the SUMO deconjugating enzyme SENP1. ► GISP SUMOylation is activity dependently regulated by synaptic long-term potentiation.