Using mass spectrometry to identify ubiquitin and ubiquitin-like protein conjugation sites.
Ubiquitin (Ub) and the ubiquitin-like proteins (Ubls) are polypeptides that are covalently conjugated to proteins and other biomolecules to modulate their turnover rate, localization, and/or function. The full range of Ubl functions is only beginning to be understood, and the wide variety of Ubl conjugates is only beginning to be identified. Moreover, how Ubl conjugation is regulated, and how Ubl conjugate populations change, e.g., throughout the cell cycle, in response to hormones, nutrients, or stress, or in various disease states, remains largely enigmatic. MS represents a powerful tool for the characterization of PTMs. However, standard sample preparation and data search methods are not amenable to the identification of many types of Ubl conjugates. Here, we describe the challenges of identifying Ub/Ubl conjugates, and propose an improved workflow for identification of Ub/Ubl conjugation sites. Considering the importance of Ubls in normal cellular physiology, and their roles in disease etiology and progression, it will be critical to develop improved high-throughput MS methods capable of efficiently identifying proteins and other biomolecules modified by these very interesting and important PTMs.
Jeram
Stanley M
SM
Ontario Cancer Institute, McLaughlin Centre for Molecular Medicine, Department of Medical Biophysics, University of Toronto, Toronto, Canada.
Srikumar
Tharan
T
Pedrioli
Patrick G A
PG
Raught
Brian
B
D000595:Amino Acid Sequence; D001665:Binding Sites; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011499:Protein Processing, Post-Translational / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D016415:Sequence Alignment; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000502:physiology; D025801:Ubiquitin / Q000737:chemistry* / Q000502:physiology; D014452:Ubiquitins / Q000737:chemistry* / Q000502:physiology
D011506:Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D014452:Ubiquitins