Precision tuning of ABA signaling by ubiquitination of ABA receptors: modulating protein activity and localization

Abstract

Ubiquitination, a form of post-translational modification, precisely orchestrates plant hormone signaling by modulating protein activity, localization, assembly, and interaction. The RING-type E3 ubiquitin ligase RING FINGER OF SEED LONGEVITY 1 and the CULLIN4 -DAMAGE-SPECIFIC DNA-BINDING PROTEIN 1-DDB1-binding WD protein-type E3 ubiquitin ligase complex promote the degradation of abscisic acid (ABA) receptors by mediating their poly-ubiquitination. In contrast, Arabidopsis DOA10A, an E3 ubiquitin ligase associated with Endoplasmic Reticulum-Associated Degradation, enhances the localization of ABA receptors to the plasma membrane through mono-ubiquitination, thereby improving their function in signal perception. Different mechanisms mediating poly-ubiquitination or mono-ubiquitination play a decisive role in determining the fate of ABA receptors.