Ubiquitination in plant nutrient utilization

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.

Relationship between Leaf Micro- and Macro-Nutrients in Top Canopy Trees in a Mixed Forest in the Upper Rio Negro in the Amazon Region

“…Studies suggest that uptake, translocation, and homeostasis of Zn, Fe, and Mn is controlled by the number of active transporters embedded in cell membranes. Ubiquitin (Ub) as well as other small Ub-like proteins able to conjugate with target proteins have important roles in uptake, trafficking, and maintenance of many plant essential nutrients [8]. Ubiquitination involves the conjugation of ubiquitin (Ub) onto lysine residues of acceptor proteins.…”

“…Comparative elemental profiles will yield valuable insight into how the plant ionome responds to the environment and provides clues to explore the genetics that control the homeostasis of the ionome [6] [7]. Physiological mechanisms that enable plants to respond to environmental conditions through the flexible modification of key regulators of cellular physiology may be highly selected in order to maintain ionic homeostasis [8].…”

Ubiquitination pathway as a target to develop abiotic stress tolerance in rice

“…As such, cells are capable of rapidly responding to the intracellular signals and to changes in environmental conditions through modifications in key regulators. 10 Ubiquitin is a protein composed of 76 amino acids, found in both the cytosol and the nucleus of eukaryotic cells. It can be covalently bound to other proteins (target proteins) so to regulate stability, function or location of the modified protein.…”

“…Furthermore, they take part in immune responses, membrane transport, DNA repair, chromatin remodeling and protein degradation. 10,[12][13][14] Ubiquitination is characterized by the combination of ubiquitin in Lys residues of acceptor proteins. 9 The process occurs through a well-known enzymatic cascade involving 3 enzymes: ubiquitin-activating (E1), ubiquitin-conjugating (E2), and ubiquitin-ligase (E3).…”

From soil to seed: micronutrient movement into and within the plant

“…However, the extent to which plants rely on ubiquitination for regulating nutrient transport and compartmentalization is still in its infancy. In a perspective article, Yates and Sadanandom (2013) highlight the importance of the role ubiquitin plays in a plant's ability to uptake and process nutrients, including recent advances in understanding how ubiquitin supports nutrient homeostasis by affecting the trafficking of membrane-bound transporters. It is possible that we need to become more mindful of ubiquitination processes in future strategies when further improving biofortification or abiotic stress tolerance.…”