SUMO (Small Ubiquitin-like Modifier) is a class of proteins structurally similar to ubiquitin, including family members such as SUMO-1, SUMO-2, and SUMO-3, among which SUMO-2 and SUMO-3 are highly homologous. SUMO is covalently attached to substrate proteins through a specific enzymatic pathway involving E1 activating enzyme, E2 conjugating enzyme, and E3 ligase. This modification process occurs in the nucleus and cytoplasm, regulating various biological responses and signaling pathways, including nuclear transport, transcriptional regulation, DNA repair, and cell cycle control. The expression of SUMO-modified genes exhibits tissue-specificity, and dysregulation of SUMOylation or mutations in related enzymes are associated with various diseases such as cancer, neurodegenerative diseases, and cardiovascular diseases.