Phosphoprotein SAK1 is a regulator of acclimation to singlet oxygen in Chlamydomonas reinhardtii
| Autor: | Matteo Pellegrini, Sabeeha S. Merchant, Krishna K. Niyogi, Heidi K. Ledford, Brian L. Chin, Setsuko Wakao, David Casero, Rachel M. Dent |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
retrograde signaling
Mutant Chlamydomonas reinhardtii Plant Biology 7. Clean energy environment and public health singlet oxygen chemistry.chemical_compound polycyclic compounds Biology (General) Singlet Oxygen biology Singlet oxygen General Neuroscience General Medicine Adaptation Physiological Cell biology Chloroplast photo-oxidative stress Medicine Biotechnology Research Article Signal Transduction inorganic chemicals QH301-705.5 Physiological Science General Biochemistry Genetics and Molecular Biology Botany Genetics Adaptation photosynthesis General Immunology and Microbiology organic chemicals Chlamydomonas other chlamydomonas biology.organism_classification Phosphoproteins Cytosol chemistry Gene Expression Regulation 13. Climate action Phosphoprotein biological sciences Retrograde signaling Biochemistry and Cell Biology |
| Zdroj: | eLife, Vol 3 (2014) eLife eLife, vol 3, iss 3 Wakao, S; Chin, BL; Ledford, HK; Dent, RM; Casero, D; Pellegrini, M; et al.(2014). Phosphoprotein SAK1 is a regulator of acclimation to singlet oxygen in Chlamydomonas reinhardtii. eLife, 2014(3). doi: 10.7554/eLife.02286. UCLA: Retrieved from: http://www.escholarship.org/uc/item/1jp2g9s8 |
| DOI: | 10.7554/eLife.02286. |
| Popis: | Singlet oxygen is a highly toxic and inevitable byproduct of oxygenic photosynthesis. The unicellular green alga Chlamydomonas reinhardtii is capable of acclimating specifically to singlet oxygen stress, but the retrograde signaling pathway from the chloroplast to the nucleus mediating this response is unknown. Here we describe a mutant, singlet oxygen acclimation knocked-out 1 (sak1), that lacks the acclimation response to singlet oxygen. Analysis of genome-wide changes in RNA abundance during acclimation to singlet oxygen revealed that SAK1 is a key regulator of the gene expression response during acclimation. The SAK1 gene encodes an uncharacterized protein with a domain conserved among chlorophytes and present in some bZIP transcription factors. The SAK1 protein is located in the cytosol, and it is induced and phosphorylated upon exposure to singlet oxygen, suggesting that it is a critical intermediate component of the retrograde signal transduction pathway leading to singlet oxygen acclimation. DOI: http://dx.doi.org/10.7554/eLife.02286.001 eLife digest Plants, algae and some bacteria use photosynthesis to extract energy from sunlight and to convert carbon dioxide into the sugars needed for growth. One by-product of photosynthesis is a highly toxic molecule called singlet oxygen. Typically, organisms deal with stressful events such as the presence of toxic molecules by producing new proteins. However, protein production is generally initiated in the nucleus of the cell, and photosynthesis is carried out in structures called chloroplasts. Cells must therefore be able to alert the nucleus to the presence of toxic levels of singlet oxygen in the chloroplasts. Like some plants that can withstand a gradual decrease in temperature, but not a sudden cold snap, the alga Chlamydomonas reinhardtii is capable of resisting high doses of singlet oxygen if it has previously been exposed to low doses of the molecule. Wakao et al. exploited this ability to hunt for algae that are unable to acclimate to singlet oxygen, and found that these cells are unable to produce a protein called SAK1. Wakao et al. reveal that many factors involved in the algae's cellular response to singlet oxygen depend on the presence of SAK1. In addition, the response of the algae cells to singlet oxygen differs to the one seen in the model plant Arabidopsis thaliana, suggesting that the two organisms have found different ways to deal with the same problem. The location of a protein in a cell can give clues to its function. SAK1 is present in the fluid surrounding cellular compartments—the cytosol—which is consistent with it acting as a signaling molecule between the chloroplast and the nucleus. Wakao et al. present further evidence for this hypothesis by demonstrating that the number of phosphate groups attached on SAK1 changes when exposed to singlet oxygen—a feature often seen in signaling proteins. In addition, part of SAK1 resembles proteins that can bind to DNA, which indicates that SAK1 may be directly involved in initiating protein production. The discovery of SAK1 represents a starting point for understanding how the site of photosynthesis, the chloroplast, communicates with the nucleus. It also has implications for developing plants and algae that have a higher tolerance to environmental stress conditions for agriculture and biofuel production. DOI: http://dx.doi.org/10.7554/eLife.02286.002 |
| Databáze: | OpenAIRE |
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