Although we cannot exclude that with different severities of ischemia, varying durations of ischemia and reperfusion, or different methods to induce the ischemic injury, the pattern of SUMO1 conjugation changes may differ, it is clear that the conjugations by SUMO1 and SUMO2/3 have distinct functions in ischemic brain injury, with SUMO1 conjugation being more common under normal conditions whereas SUMO2/3 conjugation upregulated during I/R insult. The gene discussed is SUMO2; the disease is ischemia.