Review: N-degron pathway-mediated proteostasis in stress physiology (Annu Rev Plant Biol)

The rate of most biological processes is ultimately determined by protein activity levels, which of course are determined by rate of degradation or inactivation as well as production. Dissmeyer reviews the Cys/Arg branch of the N-degron pathway (previously called the N-end rule pathway) that contributes to protein degradation. In this pathway, post-translational modifications including excision of the N-terminal Met to reveal a Cys or other “destabilizing” residue, and oxygenation and arginylation, leads to recognition, ubiquitination and protein degradation. The review discusses the biochemistry of the pathway including the mutants that helped define it in plants, and the similarities and differences between the pathways in plants, animals and fungi. The review also covers the contributions of the N-degron pathway in stress responses, including the well characterized role in the response to hypoxia. (Summary by Mary Williams) Annu Rev. Plant Biol. 10.1146/annurev-arplant-050718-095937