Ubiquitination in plant nutrient utilization

Gary Yates,Ari Sadanandom

doi:10.3389/fpls.2013.00452

Abstract

Ubiquitin (Ub) is well-established as a major modifier of signaling in eukaryotes. However, the extent to which plants rely on Ub for regulating nutrient uptake is still in its infancy. The main characteristic of ubiquitination is the conjugation of Ub onto lysine residues of acceptor proteins. In most cases the targeted protein is rapidly degraded by the 26S proteasome, the major proteolysis machinery in eukaryotic cells. The Ub-proteasome system is responsible for removing most abnormal peptides and short-lived cellular regulators, which, in turn, control many processes. This allows cells to respond rapidly to intracellular signals and changing environmental conditions. This perspective will discuss how plants utilize Ub conjugation for sensing environmental nutrient levels. We will highlight recent advances in understanding how Ub aids nutrient homeostasis by affecting the trafficking of membrane bound transporters. Given the overrepresentation of genes encoding Ub-metabolizing enzymes in plants, intracellular signaling events regulated by Ub that lead to transcriptional responses due to nutrient starvation is an under explored area ripe for new discoveries. We provide new insight into how Ub based biochemical tools can be exploited to reveal new molecular components that affect nutrient signaling. The mechanistic nature of Ub signaling indicates that dominant form of any new molecular components can be readily generated and are likely shed new light on how plants cope with nutrient limiting conditions. Finally as part of future challenges in this research area we introduce the newly discovered roles of Ub-like proteins in nutrient homeostasis.

Highlights

Gary Yates and Ari Sadanandom*Reviewed by: Kuo-Chen Yeh, Academia Sinica, Taiwan Vicente Rubio, Consejo Superior de Investigaciones Científicas, Spain
Our understanding of the layers of regulation that control the cell is deepening at a rapid rate
Much like how the discovery of microRNAs and epigenetics caused major rethinking of well-established gene control systems, protein modification processes are proving to have significant roles in the control of protein function. An example of this is ubiquitination, as a post-translational modifier it is well-known as a system involved in protein turnover, and to a lesser extent is known for its roles in membrane trafficking, DNA repair, chromatin remodeling, and hormone synthesis

Summary

Gary Yates and Ari Sadanandom*

Reviewed by: Kuo-Chen Yeh, Academia Sinica, Taiwan Vicente Rubio, Consejo Superior de Investigaciones Científicas, Spain. In most cases the targeted protein is rapidly degraded by the 26S proteasome, the major proteolysis machinery in eukaryotic cells. The Ub-proteasome system is responsible for removing most abnormal peptides and short-lived cellular regulators, which, in turn, control many processes. This allows cells to respond rapidly to intracellular signals and changing environmental conditions. This perspective will discuss how plants utilize Ub conjugation for sensing environmental nutrient levels. The mechanistic nature of Ub signaling indicates that dominant form of any new molecular components can be readily generated and are likely shed new light on how plants cope with nutrient limiting conditions. As part of future challenges in this research area we introduce the newly discovered roles of Ub-like proteins in nutrient homeostasis

INTRODUCTION

Yates and Sadanandom

CONCLUSION