2008 journal article
A new branch of endoplasmic reticulum stress signaling and the osmotic signal converge on plant-specific asparagine-rich proteins to promote cell death
JOURNAL OF BIOLOGICAL CHEMISTRY, 283(29), 20209–20219.
MeSH headings : Asparagine / metabolism; Cell Death; Cells, Cultured; Endoplasmic Reticulum / metabolism; Gene Expression Regulation, Plant; Genes, Reporter / genetics; Osmosis; Plant Leaves / cytology; Plant Leaves / genetics; Plant Leaves / growth & development; Plant Leaves / metabolism; Plant Proteins / genetics; Plant Proteins / metabolism; Protein Folding; Signal Transduction; Soybeans / cytology; Soybeans / genetics; Soybeans / growth & development; Soybeans / metabolism; Up-Regulation
TL;DR:
The results indicate that ER stress induces leaf senescence through activation of plant-specific NRPs via a novel branch of the ER stress response.
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open access via www.jbc.org (publisher PDF)
UN Sustainable Development Goal Categories
3. Good Health and Well-being
(Web of Science)
Source: Web Of Science
Added: August 6, 2018
NRPs (N-rich proteins) were identified as targets of a novel adaptive pathway that integrates endoplasmic reticulum (ER) and osmotic stress signals based on coordinate regulation and synergistic up-regulation by tunicamycin and polyethylene glycol treatments. This integrated pathway diverges from the molecular chaperone-inducing branch of the unfolded protein response (UPR) in several ways. While UPR-specific targets were inversely regulated by ER and osmotic stresses, NRPs required both signals for full activation. Furthermore, BiP (binding protein) overexpression in soybean prevented activation of the UPR by ER stress inducers, but did not affect activation of NRPs. We also found that this integrated pathway transduces a PCD signal generated by ER and osmotic stresses that result in the appearance of markers associated with leaf senescence. Overexpression of NRPs in soybean protoplasts induced caspase-3-like activity and promoted extensive DNA fragmentation. Furthermore, transient expression of NRPs in planta caused leaf yellowing, chlorophyll loss, malondialdehyde production, ethylene evolution, and induction of the senescence marker gene CP1. This phenotype was alleviated by the cytokinin zeatin, a potent senescence inhibitor. Collectively, these results indicate that ER stress induces leaf senescence through activation of plant-specific NRPs via a novel branch of the ER stress response.