A Novel Component of the Disulfide-Reducing Pathway Required for Cytochrome <i>c</i> Assembly in Plastids

Gabilly, Stéphane T.; Karamoko, Mohamed; Page, M. Dudley; Nakamoto, Stacie S.; Merchant, Sabeeha; Hamel, Patrice

doi:10.1534/genetics.110.125369

Cited by 18 publications

(43 citation statements)

References 63 publications

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“…LPA1 homologues are present in Ostreococcus and in Chlamydomonas, in which REP27 (repair-aberrant mutant of PSII) is the LPA1 homologue. In contrast to the inactivation of LPA1, inactivation of REP27 [57] does not affect the accumulation of PSII subunits other than the D1 protein [18]. REP27 is specifically required for efficient D1 turnover but is not essential for de novo biogenesis and assembly of PSII [18].…”

Section: Regulatory Factors For Psii Assemblymentioning

confidence: 87%

Regulatory factors for the assembly of thylakoid membrane protein complexes

Chi

Zhang

2012

Phil. Trans. R. Soc. B

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Major multi-protein photosynthetic complexes, located in thylakoid membranes, are responsible for the capture of light and its conversion into chemical energy in oxygenic photosynthetic organisms. Although the structures and functions of these photosynthetic complexes have been explored, the molecular mechanisms underlying their assembly remain elusive. In this review, we summarize current knowledge of the regulatory components involved in the assembly of thylakoid membrane protein complexes in photosynthetic organisms. Many of the known regulatory factors are conserved between prokaryotes and eukaryotes, whereas others appear to be newly evolved or to have expanded predominantly in eukaryotes. Their specific features and fundamental differences in cyanobacteria, green algae and land plants are discussed.

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Section: Regulatory Factors For Psii Assemblymentioning

confidence: 87%

Regulatory factors for the assembly of thylakoid membrane protein complexes

Chi

Zhang

2012

Phil. Trans. R. Soc. B

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“…These proteins define a trans-thylakoid pathway for the delivery of reductants from stroma to lumen (Lennartz et al, 2001;Page et al, 2004;Hisabori, 2006, 2010;Gabilly et al, 2010Gabilly et al, , 2011. Operation of the trans-thylakoid pathway is needed to reduce disulfides in target proteins, a process essential for photosynthesis (Lennartz et al, 2001;Page et al, 2004;Gabilly et al, 2010Gabilly et al, , 2011.…”

Section: Introductionmentioning

confidence: 99%

“…Operation of the trans-thylakoid pathway is needed to reduce disulfides in target proteins, a process essential for photosynthesis (Lennartz et al, 2001;Page et al, 2004;Gabilly et al, 2010Gabilly et al, , 2011.…”

Section: Introductionmentioning

confidence: 99%

Lumen Thiol Oxidoreductase1, a Disulfide Bond-Forming Catalyst, Is Required for the Assembly of Photosystem II inArabidopsis

et al. 2011

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Here, we identify Arabidopsis thaliana Lumen Thiol Oxidoreductase1 (LTO1) as a disulfide bond-forming enzyme in the thylakoid lumen. Using topological reporters in bacteria, we deduced a lumenal location for the redox active domains of the protein. LTO1 can partially substitute for the proteins catalyzing disulfide bond formation in the bacterial periplasm, which is topologically equivalent to the plastid lumen. An insertional mutation within the LTO1 promoter is associated with a severe photoautotrophic growth defect. Measurements of the photosynthetic activity indicate that the lto1 mutant displays a limitation in the electron flow from photosystem II (PSII). In accordance with these measurements, we noted a severe depletion of the structural subunits of PSII but no change in the accumulation of the cytochrome b 6 f complex or photosystem I. In a yeast two-hybrid assay, the thioredoxin-like domain of LTO1 interacts with PsbO, a lumenal PSII subunit known to be disulfide bonded, and a recombinant form of the molecule can introduce a disulfide bond in PsbO in vitro. The documentation of a sulfhydryl-oxidizing activity in the thylakoid lumen further underscores the importance of catalyzed thiol-disulfide chemistry for the biogenesis of the thylakoid compartment.

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“…It is suggested that electrons provided by stromal thioredoxin are transferred to the lumen via CCDA and HCF164/CCS5 to the oxidized CxxCH motif of the apocytochrome f, thereby generating the necessary sulfhydryls for heme ligation (Motohashi and Hisabori, 2006). Recently, the protein CCS4 was identified in Chlamydomonas reinhardtii that also is an essential component for heme attachment to cytochrome f (and cytochrome c 6 ); its exact role is yet unclear, but there is evidence that it is involved in the disulfidereducing pathway at the thylakoids (Gabilly et al, 2011). While heme binding in the lumen absolutely requires the transthylakoid disulfide-reducing pathway, covalent attachment of heme c n to Cys-35 of cytochrome b 6 requires the CCB (for cofactor-binding, Cytb6f complex, and cytochrome b 6 ) factors 1 to 4 at the stromal site of the membrane (Saint-Marcoux et al, 2009).…”

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confidence: 99%

The DnaJ-Like Zinc-Finger Protein HCF222 Is Required for Thylakoid Membrane Biogenesis in Plants

et al. 2017

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To understand the biogenesis of the thylakoid membrane in higher plants and to identify auxiliary proteins required to build up this highly complex membrane system, we have characterized the allelic nuclear mutants high chlorophyll fluorescence222-1 (hcf222-1) and hcf222-2 and isolated the causal gene by map-based cloning. In the ethyl methanesulfonate-induced mutant hcf222-1, the accumulation of the cytochrome b 6 f (Cytb6f) complex was reduced to 30% compared with the wild type. Other thylakoid membrane complexes accumulated to normal levels. The T-DNA knockout mutant hcf222-2 showed a more severe defect with respect to thylakoid membrane proteins and accumulated only 10% of the Cytb6f complex, accompanied by a reduction in photosystem II, the photosystem II light-harvesting complex, and photosystem I. HCF222 encodes a protein of 99 amino acids in Arabidopsis (Arabidopsis thaliana) that has similarities to the cysteine-rich zinc-binding domain of DnaJ chaperones. The insulin precipitation assay demonstrated that HCF222 has disulfide reductase activity in vitro. The protein is conserved in higher plants and bryophytes but absent in algae and cyanobacteria. Confocal fluorescence microscopy showed that a fraction of HCF222-green fluorescent protein was detectable in the endoplasmic reticulum but that it also could be recognized in chloroplasts. A fusion construct of HCF222 containing a plastid transit peptide targets the protein into chloroplasts and was able to complement the mutational defect. These findings indicate that the chloroplast-targeted HCF222 is indispensable for the maturation and/or assembly of the Cytb6f complex and is very likely involved in thiol-disulfide biochemistry at the thylakoid membrane.

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A Novel Component of the Disulfide-Reducing Pathway Required for Cytochrome c Assembly in Plastids

Cited by 18 publications

References 63 publications

Regulatory factors for the assembly of thylakoid membrane protein complexes

Regulatory factors for the assembly of thylakoid membrane protein complexes

Lumen Thiol Oxidoreductase1, a Disulfide Bond-Forming Catalyst, Is Required for the Assembly of Photosystem II inArabidopsis

The DnaJ-Like Zinc-Finger Protein HCF222 Is Required for Thylakoid Membrane Biogenesis in Plants

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