Characterizing the differential distribution and targets of Sumo1 and Sumo2 in the mouse brain

Terry R Suk; Trina T Nguyen; Zoe A Fisk; Miso Mitkovski; Haley M Geertsma; Jean-Louis A Parmasad; Meghan M Heer; Steve M Callaghan; Fritz Benseler; Nils Brose; Marilyn Tirard; Maxime W C Rousseaux

doi:10.1016/j.isci.2023.106350

Characterizing the differential distribution and targets of Sumo1 and Sumo2 in the mouse brain

iScience. 2023 Mar 9;26(4):106350. doi: 10.1016/j.isci.2023.106350. eCollection 2023 Apr 21.

Authors

Terry R Suk^{1

2

3

4}, Trina T Nguyen^{1

2

3

4}, Zoe A Fisk^{1

2

3

4}, Miso Mitkovski⁵, Haley M Geertsma^{1

2

3

4}, Jean-Louis A Parmasad^{1

2

3

4}, Meghan M Heer^{1

2

3

4}, Steve M Callaghan^{1

2

3

4}, Fritz Benseler⁶, Nils Brose⁶, Marilyn Tirard⁶, Maxime W C Rousseaux^{1

2

3

4}

Affiliations

¹ University of Ottawa Brain and Mind Research Institute, Ottawa, K1H8M5 ON, Canada.
² Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, K1H8M5 ON, Canada.
³ Eric Poulin Center for Neuromuscular Diseases, Ottawa, K1H8M5 ON, Canada.
⁴ Ottawa Institute of Systems Biology, Ottawa, K1H8M5 ON, Canada.
⁵ Light Microscopy Facility, Max Planck Institute of Multidisciplinary Sciences, City Campus, Göttingen 37075, Germany.
⁶ Department of Molecular Neurobiology, Max Planck Institute of Multidisciplinary Sciences, City Campus, Göttingen 37075, Germany.

Abstract

SUMOylation is an evolutionarily conserved eukaryotic posttranslational protein modification with broad biological relevance. Differentiating between the major small ubiquitin-like modifier (SUMO) paralogs and uncovering paralog-specific functions in vivo has long been very difficult. To overcome this problem, we generated His₆-HA-Sumo2 and HA-Sumo2 knockin mouse lines, expanding upon our existing His₆-HA-Sumo1 mouse line, to establish a "toolbox" for Sumo1-Sumo2 comparisons in vivo. Leveraging the specificity of the HA epitope, we performed whole-brain imaging and uncovered regional differences between Sumo1 and Sumo2 expression. At the subcellular level, Sumo2 was specifically detected in extranuclear compartments, including synapses. Immunoprecipitation coupled with mass spectrometry identified shared and specific neuronal targets of Sumo1 and Sumo2. Target validation using proximity ligation assays provided further insight into the subcellular distribution of neuronal Sumo2-conjugates. The mouse models and associated datasets provide a powerful framework to determine the native SUMO "code" in cells of the central nervous system.

Keywords: Imaging anatomy; Molecular biology; Neuroscience.