Small ubiquitin-like modifier 1 (SUMO1)

Small ubiquitin-like modifier 1 (SUMO1) is a ubiquitin-like protein encoded by the *SUMO1* gene, which serves as a post-translational modifier by covalently attaching to lysine side chains in target proteins—a process called SUMOylation. Unlike ubiquitin, which mainly tags proteins for degradation, SUMO1 regulates critical cellular functions including nuclear transport, transcription, apoptosis, DNA repair, protein stability, and even formation of membraneless organelles via phase separation. SUMO1 and its family members employ specific enzyme cascades for covalent attachment and removal, affecting hundreds of proteins through SUMO-interacting motifs (SIM). SUMO1 has direct implications in cardiovascular physiology via regulation of SERCA2A activity in heart muscle cells, making it a proposed therapeutic target for heart failure. It is also linked to cancer, DNA repair, orofacial clefts, and antiviral defense mechanisms. SUMO1 is not a receptor or classical enzyme, but rather a modifier that orchestrates complex molecular and cellular processes by modulating protein–protein interactions and properties.

Other names

Small ubiquitin-related modifier 1SUMO-1SMT3CSMT3H3UBL1GMP1Smt3CPIC1OFC10SentrinDAP1GAP-modifying protein 1SMT3 homolog 3Ubiquitin-homology domain protein PIC1Ubiquitin-like protein SMT3CUbiquitin-like protein UBL1SMT3 suppressor of mif two 3 homolog 1

Post-translational modification of substrate proteins (SUMOylation), altering their function, stability, localization, or interactions; Regulates transcription, DNA repair, apoptosis, and proteostasis via modulating protein interactions and stability; Enhances SERCA2A activity in cardiomyocytes (cardiac application)