ArticleThe Journal of biological chemistry2016
GUN4-Protoporphyrin IX Is a Singlet Oxygen Generator with Consequences for Plastid Retrograde Signaling.
Article in The Journal of biological chemistry, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 21 papers.
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21 citing papers in PubMed, 41 citations in OpenAlex.
- Coordinated cpSRP43 and cpSRP54 Abundance Is Essential for Tetrapyrrole Biosynthesis While cpSRP43 Is Independent of Retrograde Signaling.Plants (Basel, Switzerland) · 2025Article
- Type II metacaspase mediates light-dependent programmed cell death in Chlamydomonas reinhardtii.Plant physiology · 2024Article
- A recipe for death: Singlet oxygen and type II metacaspase mediate programmed cell death in Chlamydomonas.Plant physiology · 2024Article
- Tetrapyrrole biosynthesis pathway regulates plastid-to-nucleus signaling by controlling plastid gene expression in plants.Plant communications · 2023Article
- β-Cyclocitral Does Not Contribute to Singlet Oxygen-Signalling in Algae, but May Down-Regulate Chlorophyll Synthesis.Plants (Basel, Switzerland) · 2022Article
- Impact of Porphyrin Binding to GENOMES UNCOUPLED 4 on Tetrapyrrole BiosynthesisFrontiers in plant science · 2022Article
- GUN4 Affects the Circadian Clock and Seedlings Adaptation to Changing Light Conditions.International journal of molecular sciences · 2021Article
- Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4.Protein science : a publication of the Protein Society · 2021Article
- Orchestral manoeuvres in the light: crosstalk needed for regulation of the Chlamydomonas carbon concentration mechanism.Journal of experimental botany · 2021Review
- Bilin-dependent regulation of chlorophyll biosynthesis by GUN4.Proceedings of the National Academy of Sciences of the United States of America · 2021Article
- A Holistic Approach to Study Photosynthetic Acclimation Responses of Plants to Fluctuating Light.Frontiers in plant science · 2021Review
- Mutations of theFrontiers in plant science · 2021Article
- Transcriptome Analysis Shows Activation of Stress and Defense Responses by Silencing of Chlorophyll Biosynthetic Enzyme CHLI in Transgenic Tobacco.International journal of molecular sciences · 2020Article
- Retrograde Signaling: Understanding the Communication between Organelles.International journal of molecular sciences · 2020Review
- Biosynthesis of the modified tetrapyrroles-the pigments of life.The Journal of biological chemistry · 2020Review
- Oxygen and ROS in Photosynthesis.Plants (Basel, Switzerland) · 2020Review
- A Suppressor Mutation Partially Reverts theFrontiers in plant science · 2019Article
- Ties that bind: the integration of plastid signalling pathways in plant cell metabolism.Essays in biochemistry · 2018Review
- TheFrontiers in plant science · 2017Article
- Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms.Plant physiology · 2016Article
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Authors and funding
5 authors at 3 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The genomes uncoupled 4 (GUN4) protein is a nuclear-encoded, chloroplast-localized, porphyrin-binding protein implicated in retrograde signaling between the chloroplast and nucleus, although its exact role in this process is still unclear. Functionally, it enhances Mg-chelatase activity in the chlorophyll biosynthesis pathway. Because GUN4 is present only in organisms that carry out oxygenic photosynthesis and because it binds protoporphyrin IX (PPIX) and Mg-PPIX, it has been suggested that it prevents production of light- and PPIX- or Mg-PPIX-dependent reactive oxygen species. A chld-1/GUN4 mutant with elevated PPIX has a light-dependent up-regulation of GUN4, implicating this protein in light-dependent sensing of PPIX, with the suggestion that GUN4 reduces PPIX-generated singlet oxygen, O2(a(1)Δg), and subsequent oxidative damage (Brzezowski, P., Schlicke, H., Richter, A., Dent, R. M., Niyogi, K. K., and Grimm, B. (2014) Plant J. 79, 285-298). In direct contrast, our results show that purified GUN4 and oxidatively damaged ChlH increase the rate of PPIX-generated singlet oxygen production in the light, by a factor of 5 and 10, respectively, when compared with PPIX alone. Additionally, the functional GUN4-PPIX-ChlH complex and ChlH-PPIX complexes generate O2(a(1)Δg) at a reduced rate when compared with GUN4-PPIX. As O2(a(1)Δg) is a potential plastid-to-nucleus signal, possibly through second messengers, light-dependent O2(a(1)Δg) generation by GUN4-PPIX is proposed to be part of a signal transduction pathway from the chloroplast to the nucleus. GUN4 thus senses the availability and flux of PPIX through the chlorophyll biosynthetic pathway and also modulates Mg-chelatase activity. The light-dependent O2(a(1)Δg) generation from GUN4-PPIX is thus proposed as the first step in retrograde signaling from the chloroplast to the nucleus.
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