646 / 2019-04-29 13:49:03

Arabidopsis RING E3 ubiquitin ligase CPSR1 is involved in the proteotoxic stress response

E3 ligase,Proteotoxic stress,Translation

全体主题 > Abiotic Stress

Protein-damaging stress is caused as a secondary effect by diverse environmental stresses, which hamper the growth and development of plants. In this report, we identified a cytosolic RING E3 ligase CPSR1 (Co-translational Proteotoxic Stress RING E3 Ub Ligase 1), which might be involved in the proteotoxic stress response in Arabidopsis. Expression of CPSR1 was induced by azetidine-2-carboxylic acid (AZC), and arsenite (As), both of which caused proteotoxic stress. The cpsr1 loss-of-function mutant plant was highly sensitive to AZC and As treatments as compared to the wild-type (WT) plant. When GFP-CPSR1 was transiently expressed in tobacco leaf cells, CPSR1 was found in the cytosol and endoplasmic reticulum. Sucrose gradient fractionation assay indicated that CPSR1 was fractionated with polysomes. The cpsr1 plants displayed more sensitive phenotypes relative to WT in response to translation inhibitors hygromycin and cycloheximide. Furthermore, cpsr1 was more susceptible to heat stress than WT. In the presence of AZC, higher amount of phosphorylated form of eIF2a, a translation initiation factor, accumulated in cpsr1 seedlings than in WT plant. Collectively, these results will be discussed in the light of the suggestion that CPSR1 RING E3 ligase is involved in the proteotoxic stress response by modulating the translational process in Arabidopsis.