Ubc9 acetylation: a new route for achieving specificity in substrate SUMOylation

In contrast to the dozens of proteins involved in ubiquitination pathways, relatively few proteins control SUMO modification. Generating specificity and diversity in pathway outcomes may therefore rely on post-translational modification of pathway components and/or substrates. A new paper in The EMBO Journal identifies one such modification event, the acetylation of Ubc9, as a key regulatory step in controlling substrate selection.