Amount and activity changes of 20S proteasome modified by oxidation in salt-treated wheat root tips

Abstract

To study the response of 20S proteasome in wheat (Triticum aestivum L.) roots to salt stress, the root tips from wheat seedlings treated with 200 mM NaCl for different times were used for studying its carbonyl level, caseinolytic activity, protein abundance and other biochemical characteristics. The contents of carbonylated and ubiquitinated proteins (Ub-P) were also investigated. During this stressed process, both the productive rate of O 2 -and the content of H 2 O 2 gradually increased, with the concomitant increase in carbonyl level of total soluble proteins and 20S proteasome, together with the gradual increase in the activities of the total and 20S proteasome in salt-treated root tips. However, the amounts of 20S proteasome decreased particularly during this process. Moreover, metal-catalyzed oxidation of proteins from control plants in vitro validated that the oxidative modification also could increase the activity of 20S proteasome, but decrease its abundance. In addition, the amounts of Ub-P with molecular weights above 35 kDa remained similar to the control plants, but that below 35 kDa decreased significantly in treated root tips. The changes in the proteasome activity and amount argue in favor of the active involvement of this proteolytic system in salt-stressed plants.

Comparative proteomic analysis reveals intracellular targets for bacillomycin L to induce Rhizoctonia solani Kühn hyphal cell death

“…Increased 20S proteasome has been reported to be capable of reducing the toxic effects of environmental stress [45][46][47]. However, the expression of 20S proteasome was detected to be suppressed by bacillomycin L in this study, indicating that 20S proteasome was degraded due to severe oxidation after prolonged time of stress [48].…”

“…These proteins function in the transportation of diverse cellular materials in a directional manner along microtubules, as well as in organelle transport, karyogamy and mitosis, which are essential for appropriate cellular morphology and function [48]. In this study, kinesin-like protein was detected to be remarkably up-regulated by bacillomycin L, indicating that cellular and organelle transportation was disrupted within the injured hyphal cells and kinesin was induced to alleviate the antibiotic function of iturin.…”

Lipids and proteins—major targets of oxidative modifications in abiotic stressed plants

“…Protein carbonylation, nitration, and Snitrosylation were involved in acclimation to salinity stress in Citrus aurantium (Tanou et al 2012). In root tips of salttreated T. aestivum, the carbonyl level of total soluble proteins increased together with a gradual increase in activities of the total and 20S proteasome (Shi et al 2011). In Olea europaea cv.…”

“…Available literature reflects a differential extent of protein oxidation in plants under drought (Bartoli et al 2004;Gong et al 2005;Pyngrope et al 2013;Tian et al 2013) and salinity (Melgar et al 2009;Roychoudhury et al 2011;Shi et al 2011;Ferreira-Silva et al 2012;Tanou et al 2012). Leaf mitochondria of T. aestivum were noted to contain several-folds higher concentrations of oxidatively damaged proteins (protein carbonyls) than the chloroplasts or peroxisomes under drought stress (Bartoli et al 2004).…”

Redox Regulation in Photosynthetic Organisms: Signaling, Acclimation, and Practical Implications

“…If these couples are indeed at thermodynamic equilibrium and glutathione is in the 2-5 mM range, a typical NADP þ =NADPH ratio of 1 (340) should co-exist with a [GSH] 2 =GSSG ratio of *1,000, equivalent to GSSG in the low nanomolar range. Redox-sensitive GFP proteins have been introduced into plants by transformation (191,268) and suggested to faithfully report on the cytosolic glutathione redox potential in vivo, yielding redox potential values below À300 rather than close to À200 mV. Such values imply that cytosolic GSSG concentrations are indeed in the nanomolar range or lower.…”