Bypost-translationalcovalentconjugationtootherproteinswithinthecell,smallubiquitinrelatedmodifiers(SUMOs)areabletoregulatethecell-cyclethroughacommonenzymecascadeinvolvingthesameE1activatingandE2conjugatingenzymes.Invertebrates,threeSUMOproteinshavebeenidentified:SUMO-1,andthehighlysimilarSUMO-2andSUMO-3(oftenreferredtoasSUMO-2/3).Comparably,oneSUMOproteinisexpressedbyinvertebrates.Post-translationalmodificationsbySUMOarethoughttoregulatemultipleprocesses,includingtranscription,subcellularproteinlocalization,andthest
ABIlityofproteins.