Ubiquitination of transporters at the forefront of plant nutrition

Abstract

In plants, the tight regulation of plasmamembrane transporters is essentialto maintain nutrient homeostasis. Themechanisms controlling the abundanceof transporters, and other integralplasma membrane proteins, now come tolight. Ubiquitination appears as a majorsignal initiating cargo endocytosis andsorting into multivesicular bodies priorto degradation in the vacuole. We haveindeed demonstrated that the root irontransporter IRT1 is subjected to ubiquitin-dependent trafficking in root epidermalcells. This control is crucial to keepIRT1 levels at the cell surface low andto cope with the toxicity associated withother readily available metal substrates ofIRT1. Our work combined with recentreport on the BOR1 boron transporterestablishes ubiquitination as a conservedmechanism of plasma membrane proteintrafficking in plants and highlights itsimportance for plant nutrition. © 2011 Landes Bioscience.