Recent Advances in Ubiquitin Signals Regulating Plant Membrane Trafficking.

This article focuses on the role of ubiquitination, a reversible post-translational modification involving the attachment of the ubiquitin protein, in regulating membrane trafficking in plants. It highlights how ubiquitination of plasma membrane proteins and membrane trafficking regulators influences processes such as endocytosis, vacuolar targeting, and degradation, thereby modulating physiological responses including hormone signaling, nutrient uptake, immunity, and stress adaptation. Key examples include the ubiquitin-mediated regulation of auxin transporters (PIN proteins), brassinosteroid receptor BRI1, abscisic acid receptors (PYR/PYL/RCAR), and immune receptors like FLS2, with specific E2 and E3 enzymes and deubiquitinating enzymes (DUBs) orchestrating these pathways. The review also discusses the complexity of ubiquitin chain types, the involvement of ESCRT complexes and selective autophagy in cargo sorting, and the nuanced roles of ubiquitination beyond protein degradation, such as modulating protein activity and membrane nanodomain organization.