SUMOylation and De-SUMOylation: Wrestling with Life's Processes

The small ubiquitin-like modifier (SUMO) is a ubiquitin-like protein that covalently modifies a large number of cellular proteins. SUMO modification has emerged as an important regulatory mechanism for protein function and localization. SUMOylation is a dynamic process that is mediated by activating (E1), conjugating (E2), and ligating (E3) enzymes and readily reversed by a family of ubiquitin-like protein-specific proteases (U1p) in yeast and sentrin/SUMO-specific proteases (SENP) in human. This review will focus on the de-SUMOylating enzymes with special attention to their biological function.