Ubiquitin proteolytic system: focus on SUMO

Abstract

The small ubiquitin-like modifier proteins (Smt3 in yeast and SUMOs 1–4 in vertebrates) are members of the ubiquitin super family. Like ubiquitin, the SUMOs are protein modifiers that are covalently attached to the ϵ-amino group of lysine residues in the substrates. The application of proteomics to the SUMO field has greatly expanded both the number of known targets and the number of identified target lysines. As new refinements of proteomic techniques are developed and applied to sumoylation, an explosion of novel data is likely in the next 5 years. This ability to examine sumoylated proteins globally, rather than individually, will lead to new insights into both the functions of the individual SUMO types, and how dynamic changes in overall sumoylation occur in response to alterations in cellular environment. In addition, there is a growing appreciation for the existence of cross-talk mechanisms between the sumoylation and ubiquitinylation processes. Rather than being strictly parallel, these two systems have many points of intersection, and it is likely that the coordination of these two systems is a critical contributor to the regulation of many fundamental cellular events.

Keywords::

• cross-talk
• mass spectrometry
• proteomics
• signature tag
• STUbL
• SUMOeome
• tandem affinity purification
• Ubl

Acknowledgements

The authors would like to thank the current and past members of the Wilson laboratory for their contributions to the sumoylation field. Figure 1 was generously provided by Dr Germán Rosas-Acosta.

Financial & competing interests disclosure

This work was supported by National Institute of Health grant CA089298. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.