Merbl, Y. et al. Cell 152, 1160–1172 (2013).

Post-translational modification of proteins with ubiquitin and ubiquitin-like (Ubl) modifications has a substantial impact on protein function, stability, interactions and localization. Though ubiquitination is fairly well studied, much less is known about the functions and protein targets of other Ubl modifications. Merbl et al. now present an extensive resource, profiling the ubiquitin and six Ubl modification targets—including SUMO1, SUMO2/3, NEDD8, UFM1, FAT10 and ISG15—during mitosis. They used a previously reported protein microarray–based approach to probe active, concentrated cell extracts, detecting Ubl modifications on the spotted proteins using Ubl modification–specific antibodies. In total they identified 1,500 putative substrates; about 35% of protein targets were subject to alteration by multiple Ubl modifications, but about 80–200 targets were unique to each Ubl modification profiled. The resource provides a valuable map for detailed biological follow-up experiments.