Tirard, M. et al. Proc. Natl. Acad. Sci. USA 109, 21122–21127 (2012).

Many cellular processes, from nuclear transport to neuronal synaptic transmission, are controlled by SUMOylation. SUMOylation is a conserved post-translational modification, akin to ubiquitylation, that can affect the localizations, interactions and function or stability of many different types of protein substrates. Key SUMOylation substrates or the SUMOylation process itself are often altered in many diseases as well. However, studying SUMOylation has been technically challenging, and mammalian models that allow the identification of SUMOylated proteins in vivo have not been available. To address this, Tirard et al. developed knock-in mice expressing a tagged version of the Sumo1 gene, which encodes one of the main enzymes involved in SUMOylation. The knock-in mice, called His6-HA-SUMO1, enabled the pulldown of several new SUMOylation substrates from mouse brains.