Small ubiquitin-related modifier (SUMO)

The small ubiquitin-related modifier (SUMO) belongs to the growing family of ubiquitin-related proteins involved in posttranslational protein modification. It is present in all eukaryotic kingdoms and is highly conserved from yeast to humans. The SUMO family are composed of three types; SUMO1, SUMO2 and SUMO3. Like ubiquitin, SUMO1 is conjugated to target proteins by an enzymatic cascade involving E1, E2 enzyme and E3 lygase (known as SUMOylation). It has been known that SUMO1 substrates are abundant in cells like RanGAP1, PML and IkBa proteins. In contrast to ubiquitination, SUMOylation does not tag proteins for degradation by the 26S proteosome. SUMOylation participates in diverse events such as nuclear transport, transcriptional regulation, chromosome segregation and cell cycle control. Also the modification is associated with pathological conditions (neurodegeneration, diabetes and Inflammation).