PsbN Is Required for Assembly of the Photosystem II Reaction Center in <i>Nicotiana tabacum</i>

Torabi, Salar; Umate, Pavan; Manavski, Nikolay; Plöchinger, Magdalena; Kleinknecht, Laura; Bogireddi, Hanumakumar; Herrmann, Reinhold G.; Wanner, Gerhard; Schröder, Wolfgang P.; Meurer, Jörg

doi:10.1105/tpc.113.120444

Cited by 56 publications

(77 citation statements)

References 69 publications

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“…More than a dozen higher plant PSII-specific biogenesis/repair factors have been reported, including HCF136 (Meurer et al, 1998;Covshoff et al, 2008), LPA1 (Peng et al, 2006), FKBP-2 (Lima et al, 2006), CYP38 (Fu et al, 2007;Sirpiö et al, 2008), TLP18.3 (Sirpiö et al, 2007), LPA2 (Ma et al, 2007), LPA3 (Cai et al, 2010), PAM68 (Armbruster et al, 2010), HCF243 (Zhang et al, 2011), LTO1 (Karamoko et al, 2011), TERC (Schneider et al, 2014), LQY1 (Lu et al, 2011), HHL1 (Jin et al, 2014), and psbN (Torabi et al, 2014). Additionally, the lumenal peptidase CtpA is specifically required for C-terminal processing of the D1 protein (Anbudurai et al, 1994;Oelmüller et al, 1996;Yamamoto et al, 2001); in the absence of this C-terminal processing, no active PSII complex can be formed (Che et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

MET1 Is a Thylakoid-Associated TPR Protein Involved in Photosystem II Supercomplex Formation and Repair in Arabidopsis

et al. 2015

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ORCID ID: 0000-0001-9536-0487 (K.J.v.W.)Photosystem II (PSII) requires constant disassembly and reassembly to accommodate replacement of the D1 protein. Here, we characterize Arabidopsis thaliana MET1, a PSII assembly factor with PDZ and TPR domains. The maize (Zea mays) MET1 homolog is enriched in mesophyll chloroplasts compared with bundle sheath chloroplasts, and MET1 mRNA and protein levels increase during leaf development concomitant with the thylakoid machinery. MET1 is conserved in C3 and C4 plants and green algae but is not found in prokaryotes. Arabidopsis MET1 is a peripheral thylakoid protein enriched in stroma lamellae and is also present in grana. Split-ubiquitin assays and coimmunoprecipitations showed interaction of MET1 with stromal loops of PSII core components CP43 and CP47. From native gels, we inferred that MET1 associates with PSII subcomplexes formed during the PSII repair cycle. When grown under fluctuating light intensities, the Arabidopsis MET1 null mutant (met1) showed conditional reduced growth, near complete blockage in PSII supercomplex formation, and concomitant increase of unassembled CP43. Growth of met1 in high light resulted in loss of PSII supercomplexes and accelerated D1 degradation. We propose that MET1 functions as a CP43/CP47 chaperone on the stromal side of the membrane during PSII assembly and repair. This function is consistent with the observed differential MET1 accumulation across dimorphic maize chloroplasts.

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Section: Introductionmentioning

confidence: 99%

MET1 Is a Thylakoid-Associated TPR Protein Involved in Photosystem II Supercomplex Formation and Repair in Arabidopsis

et al. 2015

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“…The expression of the upstream located genes RbcL and AccD remained unchanged in the DpsaI-1 mutant, whereas the transcripts of the downstream located genes Ycf4, CemA, and PetA were shifted and appeared in higher amounts in the mutant as compared to the wild type. This can be explained by read-through transcription from the upstream inserted aadA cassette and displays a commonly observed effect in many similar generated knockout mutants (Zoubenko et al, 1994;Krech et al, 2012;Torabi et al, 2014b).…”

Section: Targeted Inactivation Of the Plastid Psai Gene In Tobaccomentioning

confidence: 99%

“…Antibodies specific for PsaA, PsaC, PsaD, PsaL, PsaH, PsaF, PsbH, PsbI, LHCb1, LHCb2, LHCb4, LHCb5, LHCa1, LHCa2, LHCa3, and P-LHCB2 were purchased from Agrisera. Other antibodies used were described elsewhere (Kubicki et al, 1996;Torabi et al, 2014b). The putative structure of PsaI was calculated using I-Tasser (http://zhanglab.ccmb.med.umich.edu/; Yang and Zhang, 2015).…”

Section: Protein Analysismentioning

confidence: 99%

The Low Molecular Weight Protein PsaI Stabilizes the Light-Harvesting Complex II Docking Site of Photosystem I

et al. 2016

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PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in DpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in DpsaI. Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.PSI is indisputably the most efficient solar energy converter with a potential quantum efficiency close to 100% (Nelson and Yocum, 2006;Nelson, 2009). It mediates the oxidation of plastocyanin and, subsequently, the reduction of ferredoxin resulting in the production of NADPH. The connection between PSII and PSI in the linear electron transport is provided by the cytochrome b 6 f complex. The electrochemical proton gradient build-up during the light-driven electron transport across the thylakoid membrane provides the proton motive force used for the conversion of ADP to ATP. Besides the linear electron transport, which leads to the production of both ATP and NADPH, PSI is also able to perform cyclic electron transport without the involvement of PSII and resulting solely in the generation of ATP (Yamori and Shikanai, 2016). Two routes of cyclic electron transport exist, the PROTON GRADIENT REGULATION (PGR)5/PGRL1-and the NAD(P)H dehydrogenase (NDH)-dependent pathway providing the possibility to adjust the ATP/NADPH ratio to handle changing metabolic demands and to prevent especially PSI from photoinhibition under challenging light regimes (Munekage et al., 2002;Kramer et al., 2004;Joliot and Johnson, 2011;Suorsa et al., 2012).Although the catalytic core and the function of PSI in cyanobacteria and plants remained very similar since the endosymbiotic event, its structural organization strikingly changed during plant evolution Nelson, 2008, 2009). The size of the entire plant PSI complex increased compared to the cyanobacterial PSI (Jordan et al., 2001;Amun...

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“…Antisera for CSP41, an abundant factor for stabilizing plastid RNAs (Qi et al, 2012), and of the thylakoid-associated PSII assembly factor PsbN (Torabi et al, 2014) were used as a control. The limit of detection of HCF145 is in the range of ;20 fmol, as revealed by titration analysis, indicating excellent sensitivity of the antibodies.…”

Section: Levels Of Hcf145 Decrease Upon Light Inductionmentioning

confidence: 99%

“…Soluble and membrane proteins were separated in 10% and 15% SDS-PAGE (Laemmli, 1970) and transferred to a PVDF membrane (Immobilon, 0.45µm; Millipore). Immunoblotting and antisera used were described previously (Torabi et al, 2014). HCF145 antibodies were raised against the epitope RQLNSRKDNGNTILRTC in rabbit and immunoaffinity purified as described by the manufacturer (Pineda Antikörper-Service).…”

Section: Protein and Immunological Analysismentioning

confidence: 99%

HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5′ UTR via a Newly Defined Repeat Motif in Embryophyta

et al. 2015

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ORCID IDs: 0000-0003-2740-5991 (N.M.); 0000-0003-2973-9514 (J.M.)The seedling-lethal Arabidopsis thaliana high chlorophyll fluorescence145 (hcf145) mutation leads to reduced stability of the plastid tricistronic psaA-psaB-rps14 mRNA and photosystem I (PSI) deficiency. Here, we genetically mapped the HCF145 gene, which encodes a plant-specific, chloroplast-localized, modular protein containing two homologous domains related to the polyketide cyclase family comprising 37 annotated Arabidopsis proteins of unknown function. Two further highly conserved and previously uncharacterized tandem repeat motifs at the C terminus, herein designated the transcript binding motif repeat (TMR) domains, confer sequence-specific RNA binding capability to HCF145. Homologous TMR motifs are often found as multiple repeats in quite diverse proteins of green and red algae and in the cyanobacterium Microcoleus sp PCC 7113 with unknown function. HCF145 represents the only TMR protein found in vascular plants. Detailed analysis of hcf145 mutants in Arabidopsis and Physcomitrella patens as well as in vivo and in vitro RNA binding assays indicate that HCF145 has been recruited in embryophyta for the stabilization of the psaA-psaB-rps14 mRNA via specific binding to its 59 untranslated region. The polyketide cyclase-related motifs support association of the TMRs to the psaA RNA, presumably pointing to a regulatory role in adjusting PSI levels according to the requirements of the plant cell.

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PsbN Is Required for Assembly of the Photosystem II Reaction Center in Nicotiana tabacum

Cited by 56 publications

References 69 publications

MET1 Is a Thylakoid-Associated TPR Protein Involved in Photosystem II Supercomplex Formation and Repair in Arabidopsis

MET1 Is a Thylakoid-Associated TPR Protein Involved in Photosystem II Supercomplex Formation and Repair in Arabidopsis

The Low Molecular Weight Protein PsaI Stabilizes the Light-Harvesting Complex II Docking Site of Photosystem I

HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5′ UTR via a Newly Defined Repeat Motif in Embryophyta

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