Glycation of Plant Proteins: Regulatory Roles and Interplay with Sugar Signalling?

Abstract

Glycation can be defined as an array of non-enzymatic post-translational modifications of proteins formed by their interaction with reducing carbohydrates and carbonyl products of their degradation. Initial steps of this process rely on reducing sugars and result in the formation of early glycation products—Amadori and Heyns compounds via Schiff base intermediates, whereas their oxidative degradation or reactions of proteins with α-dicarbonyl compounds yield a heterogeneous group of advanced glycation end products (AGEs). These compounds accompany thermal processing of protein-containing foods and are known to impact on ageing, pathogenesis of diabetes mellitus and Alzheimer’s disease in mammals. Surprisingly, despite high tissue carbohydrate contents, glycation of plant proteins was addressed only recently and its physiological role in plants is still not understood. Therefore, here we summarize and critically discuss the first steps done in the field of plant protein glycation during the last decade. We consider the main features of plant glycated proteome and discuss them in the context of characteristic metabolic background. Further, we address the possible role of protein glycation in plants and consider its probable contribution to protein degradation, methylglyoxal and sugar signalling, as well as interplay with antioxidant defense.

GLYI4 Plays A Role in Methylglyoxal Detoxification and Jasmonate-Mediated Stress Responses in Arabidopsis thaliana

“…In fact, it has been reported that MG forms adducts with arginine, lysine and cysteine residues of proteins, generating advanced glycation end-products (AGEs) [10,23]. AGEs adversely affect the whole organism, causing oxidative damage to key cellular components [49,50,51]. In order to assess the accumulation of MG-protein adducts in glyI4 mutant, Western blot analyses with antibody detecting MG-adducts were carried out (Figure 3).…”

Network Analyses and Data Integration of Proteomics and Metabolomics From Leaves of Two Contrasting Varieties of Sugarcane in Response to Drought

“…However, in our work, taurine reduced under drought. About the specific responses of each variety to drought, the sugars threose and rhamnose were not found at 12DI, both accumulated at PI and reduced the abundance at 4DI, in the CTC15 variety.Threose is one of the products from the oxidative degradation ascorbate, an important oxidant (Shumilina et al, 2019). Contrary to our findings, this sugar was reported to accumulate in roots of alfafa plants submitted to alkali stress (Song et al, 2017) and accumulate under drought in leaves, stem, root, and root colar in Caragana korshinskii , which is described as a highly drought tolerant plant (Zhang et al, 2017).…”

Reassessing plant glyoxalases: large family and expanding functions

“…In humans, these include hemoglobin, transcription factors and mitochondrial proteins, which may be associated with mitochondrial dysfunction in disease, aging, stress and apoptosis (Rabbani & Thornalley, 2012). In plants, studies of glycation hotspots in Arabidopsis, B. napus and recently in legume nodules indicate heavy glycation of plant proteomes in comparison to animals (Shumilina et al, 2019) and that stress conditions such as drought, heat and light primarily target glycations to the chloroplast, the site of production of higher levels of sugars (Chaplin et al, 2019).…”