The diversity of ubiquitin modifications is immense. A protein can be monoubiquitylated, multi-monoubiquitylated, and polyubiquitylated with chains varying in size and shape. Ubiquitin itself can be adorned with other ubiquitin-like proteins and smaller functional groups. Considering different combinations of post-translational modifications can give rise to distinct biological outcomes, characterizing ubiquitylated proteoforms of a given protein is paramount. In this Opinion, we review recent advances in detecting and quantifying various ubiquitin proteoforms using mass spectrometry.
Keywords: Bottom-up proteomics; Middle-down proteomics; Proteoform; Top-down proteomics; Ubiquitin; Ubiquitin chain.
Copyright © 2021 Elsevier Ltd. All rights reserved.