SUMO enzymatic cascade catalyzes the dynamic posttranslational modification process of sumoylation (i.e. transfer of SUMO protein to other proteins). The Small Ubiquitin-related Modifier, SUMO-1,[1][2] is a ubiquitin-like family member that is conjugated to its substrates through three discrete enzymatic steps (see the figure on the right): activation, involving the E1 enzyme (SAE1/SAE2);[3] conjugation, involving the E2 enzyme (UBE2I);[4][5] substrate modification, through the cooperation of the E2 and E3[6] protein ligases.[7]
SUMO pathway modifies hundreds of proteins that participate in diverse cellular processes.[8] SUMO pathway is the most studied ubiquitin-like pathway that regulates a wide range of cellular events,[9] evidenced by a large number of sumoylated proteins identified in more than ten large-scale studies.[10][11][12][13][14][15][16][17][18][19][20][excessive citations]