?
ubiquitin-like (Ubl) domain found in small ubiquitin-related modifier 1 (SUMO-1) and similar proteins SUMO (also known as "Smt3" and "sentrin" in other organisms) resembles ubiquitin (Ub) in structure, ligation to other proteins and the mechanism of ligation. Ubiquitin is a protein modifier in eukaryotes that is involved in various cellular processes including transcriptional regulation, cell cycle control, and DNA repair. Ubiquitination is comprised of a cascade of E1, E2 and E3 enzymes that results in a covalent bond between the C-terminus of Ub and the epsilon-amino group of a substrate lysine. SUMOs, like Ub, are covalently conjugated to lysine residues in a wide variety of target proteins in eukaryotic cells and regulate numerous cellular processes, such as transcription, epigenetic gene control, genomic instability, and protein degradation. Four SUMO paralogs exist in mammals, SUMO1 through SUMO4. SUMO2-SUMO4 are more closely related to each other than they are to SUMO1. SUMO1 is a binding partner of the RAD51/52 nucleoprotein filament proteins, which mediate DNA strand exchange. SUMO1 conjugation to cellular proteins has been implicated in multiple important cellular processes, such as nuclear transport, cell cycle control, oncogenesis, inflammation, and the response to virus infection.
|