Sumoylation is a post-translational modification of proteins by covalently attaching a small ubiquitin-related modifier (SUMO) to the proteins. However, unlike ubiquitination, Sumoylation does not target proteins for proteolytic degradation, it regulates protein functions in various cellular precesses, such as, nuclear-cytosolic transport, transcriptional regulation, apoptosis, protein stability, response to stress, and progression through the cell cycle.