Erasing marks: Functions of plant deubiquitylating enzymes in modulating the ubiquitin code

Plant cells need to respond to environmental stimuli and developmental signals accurately and promptly. Ubiquitylation is a reversible posttranslational modification that enables the adaptation of cellular proteostasis to internal or external factors. The different topologies of ubiquitin linkages serve as the structural basis for the ubiquitin code, which can be interpreted by ubiquitin-binding proteins or readers in specific processes. The ubiquitylation status of target proteins is regulated by ubiquitylating enzymes or writers, as well as deubiquitylating enzymes (DUBs) or erasers. DUBs can remove ubiquitin molecules from target proteins. Arabidopsis (A. thaliana) DUBs belong to 7 protein families and exhibit a wide range of functions and play an important role in regulating selective protein degradation processes, including proteasomal, endocytic, and autophagic protein degradation. DUBs also shape the epigenetic landscape and modulate DNA damage repair processes. In this review, we summarize the current knowledge on DUBs in plants, their cellular functions, and the molecular mechanisms involved in the regulation of plant DUBs.