Small ubiquitin-related modifier-1: Wrestling with protein regulation.

Small ubiquitin-related modifier-1 (SUMO-1), a member of the SUMO family, is evolutionally conserved from yeast to humans. First identified in 1997, the active 97 amino acid protein conjugates to and modifies a wide variety of target proteins. Through post-translational SUMOylation of cellular proteins, SUMO-1 is involved in a myriad of biologically important events such as cell cycle progression, the maintenance of genome integrity, nuclear transport and apoptosis. Interestingly, SUMO-1 has been suggested to have the ability to act as an ubiquitin antagonist, with which it shares 18% identity. Given its wide variety of functions, it follows that alterations to this molecule could be implicated in many disease states. To date, dysregulated SUMOylation has been implicated in several neurodegenerative disorders, heart disease and cancer. This highlights not only the need for further research but also the potential of SUMO-1 as a therapeutic target.