| abstract |
ubiquitin-like (Ubl) domain found in Saccharomyces cerevisiae ubiquitin-like protein Smt3p and similar proteins. Smt3 (Suppressor of Mif Two 3) was originally isolated as a high-copy suppressor of a mutation in MIF2, the gene of a centromere binding protein in S. cerevisiae. Smt3p is the yeast homolog of small ubiquitin-related modifier (SUMO) proteins that are involved in post-translational protein modification called SUMOylation, covalently attaching to and detaching from other proteins in cells to modify their function. SUMO resembles ubiquitin (Ub) in its structure, its ability to be ligated to other proteins, as well as in 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. Smt3p plays essential roles in cell-cycle regulation and chromosome segregation in budding yeast. It interacts with different modification enzymes, and regulates their functions through linking covalently to its targets. |