Ubiquitin-like protein that can be covalently attached to proteins as a monomer or a lysine-linked polymer. Covalent attachment via an isopeptide bond to its substrates requires prior activation by the E1 complex SAE1-SAE2 and linkage to the E2 enzyme UBE2I, and can be promoted by E3 ligases such as PIAS1-4, RANBP2 or CBX4. This post-translational modification on lysine residues of proteins plays a crucial role in a number of cellular processes such as nuclear transport, DNA replication and repair, mitosis and signal transduction. Involved for instance in targeting RANGAP1 to the nuclear pore complex protein RANBP2. Polymeric SUMO1 chains are also susceptible to polyubiquitination which functions as a signal for proteasomal degradation of modified proteins. May also regulate a network of genes involved in palate development. Interacts with SAE2, UBE2I, RANBP2, PIAS1 and PIAS2. Interacts with PARK2. Covalently attached to a number of proteins such as IKFZ1, PML, RANGAP1, HIPK2, SP100, p53, p73-alpha, MDM2, JUN, DNMT3B and TDG. Also interacts with HIF1A, HIPK2, HIPK3, CHD3, EXOSC9, RAD51 and RAD52. Interacts with USP25 (via ts SIM domain); the interaction weakly sumoylates USP25. Belongs to the ubiquitin family. SUMO subfamily. Note: This description may include information from UniProtKB.
Protein type: Nuclear receptor co-regulator; Ubiquitin-like modifier
Molecular Function: protein binding; ubiquitin protein ligase binding; transcription factor binding; SUMO ligase activity
Biological Process: negative regulation of transcription factor activity; cytokine and chemokine mediated signaling pathway; PML body organization and biogenesis; palate development; DNA repair; post-translational protein modification; negative regulation of DNA binding; regulation of protein localization; protein sumoylation; positive regulation of protein complex assembly; cellular protein metabolic process; positive regulation of proteasomal ubiquitin-dependent protein catabolic process; negative regulation of transcription, DNA-dependent
Alt. Names/Synonyms: DAP1; GAP modifying protein 1; GAP-modifying protein 1; GMP1; OFC10; PIC1; SENP2; Sentrin; Small ubiquitin-related modifier 1; SMT3; SMT3 homolog 3; SMT3 suppressor of mif two 3 homolog 1 (S. cerevisiae); SMT3C; SMT3H3; SUMO-1; SUMO1; Ubiquitin-homology domain protein PIC1; Ubiquitin-like protein SMT3C; Ubiquitin-like protein UBL1; UBL1
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.