| Gene/metabolite/process . | Cyanobacteria . |
|---|---|
| Selenium-containing GSH peroxidase 4 (GPX4) | The genome of Synechocystis sp. PCC 6803 encodes two gpx-like proteins annotated as GPX1 (slr1171) and GPX2 (slr1992) with high similarity to higher plants and mammals. In vitro experiments show that they use unsaturated fatty acid hydroperoxides or alkyl hydroperoxides as electron acceptors (Gaber et al., 2001). |
| FSP1–ubiquinol | Synechocystis sp. PCC 6803 encodes one dihydroorotate dehydrogenase (slr1418) that catalyzes the conversion of dihydroorotate to orotate with quinone or plastoquinone as electron acceptor (Nara et al., 2000; Baers et al., 2019). |
| Dihydroorotate dehydrogenase–ubiquinol | |
| SLC7A11 transmembrane protein, a key component of the cystine/glutamate transporter system xc– | Unknown. BlastP searches using cystine/glutamate transporter [Q9UPY5 (XCT_HUMAN)] as query against cyanobacterial genomes retrieved amino acid permeases (this work). |
| GSH | Key antioxidant involved in the protection against ROS (Latifi et al., 2009). Cell death induced by heat (50°C) is correlated with GSH content in Synechocystis sp. PCC 6803 (Suginaka et al., 1999; this work). External addition of GSH prevents cell death in cultures exposed to heat (50°C; this work). |
| ACSL4 | Unknown. Acyl-acyl carrier protein synthetaseof Synechocystis sp. PCC 6803 (SynAas, Slr1609, homologue of Arabidopsis LACS9) recycles free fatty acids, and it is also involved in the transfer of free fatty acids across membranes by vectorial acylation (Kaczmarzyk and Fulda, 2010; von Berlepsch et al., 2012). |
| PUFAs | Generally present in cyanobacterial membranes. The unsaturation of fatty acids in membrane lipids enhances the tolerance to salt stress and is essential for low temperature tolerance in Synechocystis sp. PCC 6803 (Allakhverdiev et al., 1999; Singh et al., 2002). Cell death induced by heat (50°C) is prevented by supplementation with deuterated PUFAs (this work). |
| Lipid peroxidation | Measured in several cyanobacteria under stress conditions (Maeda et al., 2005; Latifi et al., 2009; Lee et al., 2018). |
| LOXs | Unknown. Genes with homology to LOXs (ALOX genes) have been found in some cyanobacteria (Hansen et al., 2013). |
| Vitamin E (α-tocopherol) | Tocopherols have a role in protecting Synechocystis sp. PCC 6803 from lipid peroxidation and high light stress (Maeda et al., 2005). |
| Autophagy | Cyanobacteria have approximately 10 homologues of autophagy genes, which suggests the prokaryotic origin of some autophagy-related proteins (Yang et al., 2016). |
| Gene/metabolite/process . | Cyanobacteria . |
|---|---|
| Selenium-containing GSH peroxidase 4 (GPX4) | The genome of Synechocystis sp. PCC 6803 encodes two gpx-like proteins annotated as GPX1 (slr1171) and GPX2 (slr1992) with high similarity to higher plants and mammals. In vitro experiments show that they use unsaturated fatty acid hydroperoxides or alkyl hydroperoxides as electron acceptors (Gaber et al., 2001). |
| FSP1–ubiquinol | Synechocystis sp. PCC 6803 encodes one dihydroorotate dehydrogenase (slr1418) that catalyzes the conversion of dihydroorotate to orotate with quinone or plastoquinone as electron acceptor (Nara et al., 2000; Baers et al., 2019). |
| Dihydroorotate dehydrogenase–ubiquinol | |
| SLC7A11 transmembrane protein, a key component of the cystine/glutamate transporter system xc– | Unknown. BlastP searches using cystine/glutamate transporter [Q9UPY5 (XCT_HUMAN)] as query against cyanobacterial genomes retrieved amino acid permeases (this work). |
| GSH | Key antioxidant involved in the protection against ROS (Latifi et al., 2009). Cell death induced by heat (50°C) is correlated with GSH content in Synechocystis sp. PCC 6803 (Suginaka et al., 1999; this work). External addition of GSH prevents cell death in cultures exposed to heat (50°C; this work). |
| ACSL4 | Unknown. Acyl-acyl carrier protein synthetaseof Synechocystis sp. PCC 6803 (SynAas, Slr1609, homologue of Arabidopsis LACS9) recycles free fatty acids, and it is also involved in the transfer of free fatty acids across membranes by vectorial acylation (Kaczmarzyk and Fulda, 2010; von Berlepsch et al., 2012). |
| PUFAs | Generally present in cyanobacterial membranes. The unsaturation of fatty acids in membrane lipids enhances the tolerance to salt stress and is essential for low temperature tolerance in Synechocystis sp. PCC 6803 (Allakhverdiev et al., 1999; Singh et al., 2002). Cell death induced by heat (50°C) is prevented by supplementation with deuterated PUFAs (this work). |
| Lipid peroxidation | Measured in several cyanobacteria under stress conditions (Maeda et al., 2005; Latifi et al., 2009; Lee et al., 2018). |
| LOXs | Unknown. Genes with homology to LOXs (ALOX genes) have been found in some cyanobacteria (Hansen et al., 2013). |
| Vitamin E (α-tocopherol) | Tocopherols have a role in protecting Synechocystis sp. PCC 6803 from lipid peroxidation and high light stress (Maeda et al., 2005). |
| Autophagy | Cyanobacteria have approximately 10 homologues of autophagy genes, which suggests the prokaryotic origin of some autophagy-related proteins (Yang et al., 2016). |
Several key genes, metabolites, and processes relevant to ferroptosis described in humans (Dixon et al., 2012; Conrad et al., 2018) are shown as well as a summary of their potential role in cyanobacteria.