A new function for an old cytochrome?

Molina-Heredia, Fernando P.; Wastl, Jürgen; Navarro, José A.; Bendall, Derek S.; Hervás, Manuel; Howe, Christopher J.; Rosa, Miguel Á. De la

doi:10.1038/424033b

Cited by 73 publications

(53 citation statements)

References 6 publications

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“…This might facilitate the redistribution of Cu in Chlamydomonas that also expresses a cytochrome c 6 , which can functionally replace PC (Merchant et al, 2006). However, in plants, which do not have a functional cytochrome c 6 (Molina-Heredia et al, 2003) and where PC is essential (Weigel et al, 2003), there is no experimental evidence for the induction of PC-specific proteolytic activity. It seems likely that apoPC without its cofactor is more rapidly turned over (see discussion in Abdel-Ghany, 2009).…”

Section: Discussionmentioning

confidence: 98%

Spatiotemporal Analysis of Copper Homeostasis in Populus trichocarpa Reveals an Integrated Molecular Remodeling for a Preferential Allocation of Copper to Plastocyanin in the Chloroplasts of Developing Leaves

et al. 2011

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Plastocyanin, which requires copper (Cu) as a cofactor, is an electron carrier in the thylakoid lumen and essential for photoautotrophic growth of plants. The Cu microRNAs, which are expressed during Cu deprivation, down-regulate several transcripts that encode for Cu proteins. Since plastocyanin is not targeted by the Cu microRNAs, a cofactor economy model has been proposed in which plants prioritize Cu for use in photosynthetic electron transport. However, defects in photosynthesis are classic symptoms of Cu deprivation, and priorities in Cu cofactor delivery have not been determined experimentally. Using hydroponically grown Populus trichocarpa (clone Nisqually-1), we have established a physiological and molecular baseline for the response to Cu deficiency. An integrated analysis showed that Cu depletion strongly reduces the activity of several Cu proteins including plastocyanin, and consequently, photosynthesis and growth are decreased. Whereas plastocyanin mRNA levels were only mildly affected by Cu depletion, this treatment strongly affected the expression of other Cu proteins via Cu microRNA-mediated transcript down-regulation. Polyphenol oxidase was newly identified as Cu regulated and targeted by a novel Cu microRNA, miR1444. Importantly, a spatiotemporal analysis after Cu resupply to previously depleted plants revealed that this micronutrient is preferentially allocated to developing photosynthetic tissues. Plastocyanin and photosynthetic electron transport efficiency were the first to recover after Cu addition, whereas recovery of the other Cu-dependent activities was delayed. Our findings lend new support to the hypothesis that the Cu microRNAs serve to mediate a prioritization of Cu cofactor use. These studies also highlight poplar as an alternative sequenced model for spatiotemporal analyses of nutritional homeostasis.

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Section: Discussionmentioning

confidence: 98%

Spatiotemporal Analysis of Copper Homeostasis in Populus trichocarpa Reveals an Integrated Molecular Remodeling for a Preferential Allocation of Copper to Plastocyanin in the Chloroplasts of Developing Leaves

et al. 2011

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“…Like plastocyanin, cytochrome c 6 relies on electrostatic interactions for electron transfer, although the polarity of these can differ between plants and cyanobacteria (De La Rosa et al 2002). Although a cytochrome c 6 isoform was discovered in plants (Gupta et al 2002;Wastl et al 2002), it does not seem functionally homologous to plant plastocyanin and possesses a much more reducing midpoint potential of +140 mV (Molina-Heredia et al 2003).…”

Section: Plastocyanin and Cytochrome Cmentioning

confidence: 99%

Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins

et al. 2017

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“…The most straightforward explanation for this phenotype is a very severe inhibition of Cu delivery to plastocyanin, which is the only protein that can accept electrons from the cytochrome b 6 f complex in vitro (Molina-Heredia et al, 2003). Indeed, plants with insertions in both plastocyanin genes are seedling-lethal on soil (Weigel et al, 2003).…”

Section: The Significance Of Cu Delivery For Photosynthesis In Plantsmentioning

confidence: 99%

Two P-Type ATPases Are Required for Copper Delivery in Arabidopsis thaliana Chloroplasts

et al. 2005

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Copper delivery to the thylakoid lumen protein plastocyanin and the stromal enzyme Cu/Zn superoxide dismutase in chloroplasts is required for photosynthesis and oxidative stress protection. The copper delivery system in chloroplasts was characterized by analyzing the function of copper transporter genes in Arabidopsis thaliana. Two mutant alleles were identified of a previously uncharacterized gene, PAA2 (for P-type ATPase of Arabidopsis), which is required for efficient photosynthetic electron transport. PAA2 encodes a copper-transporting P-type ATPase with sequence similarity to PAA1, which functions in copper transport in chloroplasts. Both proteins localized to the chloroplast, as indicated by fusions to green fluorescent protein. The PAA1 fusions were found in the chloroplast periphery, whereas PAA2 fusions were localized in thylakoid membranes. The phenotypes of paa1 and paa2 mutants indicated that the two transporters have distinct functions: whereas both transporters are required for copper delivery to plastocyanin, copper delivery to the stroma is inhibited only in paa1 but not in paa2. The effects of paa1 and paa2 on superoxide dismutase isoform expression levels suggest that stromal copper levels regulate expression of the nuclear genes IRON SUPEROXIDE DISMUTASE1 and COPPER/ZINC SUPEROXIDE DISMUTASE2. A paa1 paa2 double mutant was seedling-lethal, underscoring the importance of copper to photosynthesis. We propose that PAA1 and PAA2 function sequentially in copper transport over the envelope and thylakoid membrane, respectively.

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A new function for an old cytochrome?

Cited by 73 publications

References 6 publications

Spatiotemporal Analysis of Copper Homeostasis in Populus trichocarpa Reveals an Integrated Molecular Remodeling for a Preferential Allocation of Copper to Plastocyanin in the Chloroplasts of Developing Leaves

Spatiotemporal Analysis of Copper Homeostasis in Populus trichocarpa Reveals an Integrated Molecular Remodeling for a Preferential Allocation of Copper to Plastocyanin in the Chloroplasts of Developing Leaves

Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins

Two P-Type ATPases Are Required for Copper Delivery in Arabidopsis thaliana Chloroplasts

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