The ‘dark matter’ of ubiquitin-mediated processes: opportunities and challenges in the identification of ubiquitin-binding domains

Ubiquitin modifications of target proteins act to localise, direct and specify a diverse range of cellular processes, many of which are biomedically relevant. To allow this diversity, ubiquitin modifications exhibit remarkable complexity, determined by a combination of polyubiquitin chain length, linkage type, numbers of ubiquitin chains per target, and decoration of ubiquitin with other small modifiers. However, many questions remain about how...