Abstract
Monoubiquitination is a post-translational modification (PTM), through which a single ubiquitin molecule is covalently conjugated to a lysine residue of the target protein. Monoubiquitination regulates the activity, subcellular localization, protein-protein interactions, or endocytosis of the substrate. In doing so, monoubiquitination is implicated in diverse cellular processes, including gene transcription, endocytosis, signal transduction, cell death, and DNA damage repair, which in turn regulate cell-cycle progression, survival, proliferation, and stress response. In this review, we summarize the functions of monoubiquitination and discuss how this PTM modulates homeostasis and cancer.