Small ubiquitin-related modifier 1 (SUMO1),a member of the ubiquitin family and SUMO subfamily, is also known as GAP-modifying protein 1 (GMP1), SMT3 homolog 3, ubiquitin-homology domain protein PIC1 and ubiquitin-like protein UBL1,which contains one ubiquitin-like domain. Cleavage of precursor form by SENP1 or SENP2 is necessary for the function of SUMO1. Polymeric SUMO1 chains undergo polyubiquitination by RNF4. SUMO1 may also regulate a network of genes involved in palate development.SUMO1 plays an important role in modulation of NOX activity required for ROS generation.