Ascorbate peroxidase 2 of Chlamydomonas reinhardtii is involved in the regulation of the plastocyanin levels

Caccamo, Anna; Luna, Felix Vega de; Amelii, Antonello; Herinckx, Gaëtan; Ruys, Sébastien Pyr dit; Vertommen, Didier; Cardol, Pierre; Messens, Joris; Remacle, Claire

doi:10.1016/j.freeradbiomed.2022.06.104

Cited by 2 publications

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“…For that purpose, 30 µg of wt-soluble extracts was diluted by a factor two (100%, 50, 25, 12.5, 6.25, 3.125%) and the immunoblot was labeled with the APX2 antibodies. A signal corresponding to the expected size of the mature form (24 kDa, Caccamo et al. 2023 ) was detected in wt-soluble extracts and absent in the apx2 mutants.…”

Section: Resultsmentioning

confidence: 96%

“…S1A ). Since our previous work demonstrated that APX2 is chloroplast-localized and exhibits a TAT motif for targeting the lumen of the thylakoids ( Caccamo et al. 2023 ), chloroplast fractions of the wt and of one of the apx2 mutants (the apx2-1 allele) were isolated and analyzed on immunoblot ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Our previous in vitro work demonstrated that recombinant APX2 binds copper and that copper-loaded APX2 interferes with the copper-binding capabilities of plastocyanin ( Caccamo et al. 2023 ).…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the recombinant protein does not use ascorbate as an electron donor for reduction of H 2 O 2 , confirming its classification to the APX-R family. Additionally, it binds both copper and heme, and it modulates the copper-binding capabilities of plastocyanin in vitro ( Caccamo et al. 2023 ).…”

Section: Introductionmentioning

confidence: 99%

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APX2 Is an Ascorbate Peroxidase–Related Protein that Regulates the Levels of Plastocyanin in Chlamydomonas

Caccamo,

Vega de Luna,

Misztak

et al. 2024

Plant and Cell Physiology

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The function of ascorbate peroxidase–related (APX-R) proteins, present in all green photosynthetic eukaryotes, remains unclear. This study focuses on APX-R from Chlamydomonas reinhardtii, namely, ascorbate peroxidase 2 (APX2). We showed that apx2 mutants exhibited a faster oxidation of the photosystem I primary electron donor, P700, upon sudden light increase and a slower re-reduction rate compared to the wild type, pointing to a limitation of plastocyanin. Spectroscopic, proteomic and immunoblot analyses confirmed that the phenotype was a result of lower levels of plastocyanin in the apx2 mutants. The redox state of P700 did not differ between wild type and apx2 mutants when the loss of function in plastocyanin was nutritionally complemented by growing apx2 mutants under copper deficiency. In this case, cytochrome c6 functionally replaces plastocyanin, confirming that lower levels of plastocyanin were the primary defect caused by the absence of APX2. Overall, the results presented here shed light on an unexpected regulation of plastocyanin level under copper-replete conditions, induced by APX2 in Chlamydomonas.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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APX2 Is an Ascorbate Peroxidase–Related Protein that Regulates the Levels of Plastocyanin in Chlamydomonas

Caccamo,

Vega de Luna,

Misztak

et al. 2024

Plant and Cell Physiology

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“…APX is a crucial type of antioxidant enzyme in plants, responsible for clearing excess H 2 O 2 . The increased activity of APX2 promotes the plant's ability to eliminate excessive ROS during oxidative stress (Caccamo et al, 2023). Thus, it can be speculated that the overexpression of AnDREB5.1 promoted the expression of genes encoding antioxidant enzymes, and raised the capacity to clear ROS, thereby improving the resistance of tobacco to osmotic stress and cold adversity.…”

Section: Discussionmentioning

confidence: 99%

AnDREB5.1, a A5 group DREB gene from desert shrub Ammopiptanthus nanus, confers osmotic and cold stress tolerances in transgenic tobacco

Zhu,

Zheng,

Cao

et al. 2024

Physiologia Plantarum

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The Dehydration‐Responsive Element Binding (DREB) subfamily of transcription factors plays crucial roles in plant abiotic stress response. Ammopiptanthus nanus (A. nanus) is an eremophyte exhibiting remarkable tolerance to environmental stress and DREB proteins may contribute to its tolerance to water deficit and low‐temperature stress. In the present study, an A. nanus DREB A5 group transcription factor gene, AnDREB5.1, was isolated and characterized in terms of structure and function in abiotic stress tolerance. AnDREB5.1 protein is distributed in the nucleus, possesses transactivation capacity, and is capable of binding to DRE core cis‐acting element. The transcription of AnDREB5.1 was induced under osmotic and cold stress. Tobacco seedlings overexpressing AnDREB5.1 displayed higher tolerance to cold stress, osmotic stress, and oxidative stress compared to wild‐type tobacco (WT). Under osmotic and cold stress, overexpression of AnDREB5.1 increased antioxidant enzyme activity in tobacco leaves, inhibiting excessive elevation of ROS levels. Transcriptome sequencing analysis showed that overexpression of AnDREB5.1 raised the tolerance of transgenic tobacco seedlings to abiotic stress by regulating multiple genes, including antioxidant enzymes, transcription factors, and stress‐tolerant related functional genes like NtCOR413 and NtLEA14. This study provides new evidence for understanding the potential roles of the DREB A5 subgroup members in plants.

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Ascorbate peroxidase 2 of Chlamydomonas reinhardtii is involved in the regulation of the plastocyanin levels

Cited by 2 publications

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APX2 Is an Ascorbate Peroxidase–Related Protein that Regulates the Levels of Plastocyanin in Chlamydomonas

APX2 Is an Ascorbate Peroxidase–Related Protein that Regulates the Levels of Plastocyanin in Chlamydomonas

AnDREB5.1, a A5 group DREB gene from desert shrub Ammopiptanthus nanus, confers osmotic and cold stress tolerances in transgenic tobacco

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