Plant Signaling: Ubiquitin Pulls the Trigger on Chloroplast Degradation

Ling, Qihua; Jarvis, Paul

doi:10.1016/j.cub.2015.11.022

Cited by 22 publications

(28 citation statements)

References 20 publications

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“…The Arabidopsis ferrochelatase2 (fc2) mutant is defective in converting of protoporphyrin IX (ProtoIX) to heme, and the elevated level of ProtoIX acts as a photosensitizer and generates 1 O 2 that damages chloroplasts (11,21). The damaged chloroplasts are then ubiquitinated on the outer envelope via PUB4 ubiquitin ligase and degraded (11,22). Another experimental system is the Arabidopsis chlorophyll b-less chlorina (ch1) mutant that is devoid of PSII antenna complexes (23).…”

Section: Significancementioning

confidence: 99%

The Arabidopsis SAFEGUARD1 suppresses singlet oxygen-induced stress responses by protecting grana margins

Wang

Leister

Guan

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Singlet oxygen (1O2), the major reactive oxygen species (ROS) produced in chloroplasts, has been demonstrated recently to be a highly versatile signal that induces various stress responses. In thefluorescent(flu) mutant, its release causes seedling lethality and inhibits mature plant growth. However, these drastic phenotypes are suppressed when EXECUTER1 (EX1) is absent in theflu ex1double mutant. We identified SAFEGUARD1 (SAFE1) in a screen of ethyl methanesulfonate (EMS) mutagenizedflu ex1plants for suppressor mutants with aflu-like phenotype. Influ ex1 safe1, all1O2-induced responses, including transcriptional rewiring of nuclear gene expression, return to levels, such as, or even higher than, those influ. Without SAFE1, grana margins (GMs) of chloroplast thylakoids (Thys) are specifically damaged upon1O2generation and associate with plastoglobules (PGs). SAFE1 is localized in the chloroplast stroma, and release of1O2induces SAFE1 degradation via chloroplast-originated vesicles. Our paper demonstrates thatflu-produced1O2triggers an EX1-independent signaling pathway and proves that SAFE1 suppresses this signaling pathway by protecting GMs.

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Section: Significancementioning

confidence: 99%

The Arabidopsis SAFEGUARD1 suppresses singlet oxygen-induced stress responses by protecting grana margins

Wang

Leister

Guan

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…Proteins are exported from mitochondria, chloroplasts and peroxisomes and the endoplasmic reticulum (ER) (Figure 1). The best characterised mechanisms of protein export are involved in protein degradation and in organelle quality control via the cytosolic Ubiquitin-proteasome system (UPSl (Bragoszewski et al, 2017;Kao et al, 2018;Ling and Jarvis, 2016). In peroxisomes, for example, an ER associated degradation (ERAD)-like system exports the import receptor PEX5 from the peroxisome membrane to perform further rounds of import.…”

Section: Protein Import and Exportmentioning

confidence: 99%

On the move: redox-dependent protein relocation in plants

Foyer

Baker

Wright

et al. 2019

Journal of Experimental Botany

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“…This would provide a link to a recently made observation. Ling and Jarvis (2016) identified an OEM E3 ubiquitin ligase (SP1), which upon abiotic stress marks TOC components for degradation. It must be clarified if phosphorylation enhances this effect, which would provide new insights into the regulation made by phosphorylation.…”

Section: Potential Involvement Of Import Regulation In Plant Acclimatmentioning

confidence: 99%

Import of Soluble Proteins into Chloroplasts and Potential Regulatory Mechanisms

2017

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Chloroplasts originated from an endosymbiotic event in which a free-living cyanobacterium was engulfed by an ancestral eukaryotic host. During evolution the majority of the chloroplast genetic information was transferred to the host cell nucleus. As a consequence, proteins formerly encoded by the chloroplast genome are now translated in the cytosol and must be subsequently imported into the chloroplast. This process involves three steps: (i) cytosolic sorting procedures, (ii) binding to the designated receptor-equipped target organelle and (iii) the consecutive translocation process. During import, proteins have to overcome the two barriers of the chloroplast envelope, namely the outer envelope membrane (OEM) and the inner envelope membrane (IEM). In the majority of cases, this is facilitated by two distinct multiprotein complexes, located in the OEM and IEM, respectively, designated TOC and TIC. Plants are constantly exposed to fluctuating environmental conditions such as temperature and light and must therefore regulate protein composition within the chloroplast to ensure optimal functioning of elementary processes such as photosynthesis. In this review we will discuss the recent models of each individual import stage with regard to short-term strategies that plants might use to potentially acclimate to changes in their environmental conditions and preserve the chloroplast protein homeostasis.

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Plant Signaling: Ubiquitin Pulls the Trigger on Chloroplast Degradation

Abstract: Diverse proteolytic pathways regulate chloroplasts. Recent work has revealed significant new roles for chloroplast ubiquitination in stress adaptation, involving targeted protein removal through the ubiquitin-proteasome system, or selective, whole-chloroplast degradation.

Cited by 22 publications

References 20 publications

The Arabidopsis SAFEGUARD1 suppresses singlet oxygen-induced stress responses by protecting grana margins

The Arabidopsis SAFEGUARD1 suppresses singlet oxygen-induced stress responses by protecting grana margins

On the move: redox-dependent protein relocation in plants

Import of Soluble Proteins into Chloroplasts and Potential Regulatory Mechanisms

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