Academic Journal
View in EDS

PGR5 is needed for regulation of ATP synthase in plant chloroplasts.

Bibliographic Details
Title: PGR5 is needed for regulation of ATP synthase in plant chloroplasts.
Authors: Nikkanen L; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland. Electronic address: lenikk@utu.fi., Woodford R; School of Biological Sciences, Monash University, Australia., Andersin E; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland., Wey LT; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland., Ermakova M; School of Biological Sciences, Monash University, Australia., Rintamäki E; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland.
Source: Biochimica et biophysica acta. Bioenergetics [Biochim Biophys Acta Bioenerg] 2026 Nov 01; Vol. 1867 (4), pp. 149596. Date of Electronic Publication: 2026 May 29.
Publication Type: Journal Article
Language: English
Journal Info: Publisher: Elsevier Country of Publication: Netherlands NLM ID: 101731706 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-2650 (Electronic) Linking ISSN: 00052728 NLM ISO Abbreviation: Biochim Biophys Acta Bioenerg Subsets: MEDLINE
Imprint Name(s): Original Publication: Amsterdam : Elsevier
MeSH Terms: Arabidopsis*/genetics , Arabidopsis*/enzymology , Arabidopsis*/metabolism , Arabidopsis Proteins*/metabolism , Arabidopsis Proteins*/genetics , Chloroplasts*/enzymology , Chloroplasts*/metabolism , Chloroplasts*/genetics , Photosynthetic Reaction Center Complex Proteins*/metabolism , Photosynthetic Reaction Center Complex Proteins*/genetics , Chloroplast Proton-Translocating ATPases*/metabolism, Light ; Oxidation-Reduction ; Proton-Motive Force ; Electron Transport ; Photosynthesis
Abstract: Regulation of proton motive force (pmf) via ATP synthase activity is a critical mechanism by which photosynthetic organisms maintain redox homeostasis and control the activation and inactivation of photoprotective responses under fluctuating light conditions. Here, we used time-resolved electrochromic shift measurements to investigate pmf dynamics in the C3 model plant Arabidopsis thaliana and the C4 model grass Setaria viridis. Our results reveal that ATP synthase is dynamically regulated during light fluctuations, but in Arabidopsis this regulation could not be explained by the established light-induced reduction of the CF₁γ subunit by thioredoxins, suggesting alternative control mechanisms. The PROTON GRADIENT REGULATION 5 (PGR5) protein, previously proposed to facilitate cyclic electron transport (CET) in plants and algae, also has a potential role in regulation of ATP synthase. We therefore investigated pmf dynamics, cytochrome f redox changes, and linear and cyclic PSI electron transport rates in WT and pgr5 knock-out mutants and revealed that while PGR5 was not required for CET, it was needed for downregulating ATP synthase under high irradiance in both species. Furthermore, in Arabidopsis disturbance of thiol redox regulation by addition of N-ethylmaleimide resulted in downregulation of ATP synthase conductivity in WT but not in pgr5 mutants, and PGR5 interacted with CF₁γ in planta. We suggest that PGR5 functions as a conserved thiol redox state dependent inhibitor of chloroplast ATP synthase under high light, contributing to pmf retention and photoprotection.
(Copyright © 2026. Published by Elsevier B.V.)
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Lauri Nikkanen reports financial support was provided by Research Council of Finland. Eevi Rintamäki reports financial support was provided by Research Council of Finland. Eevi Rintamäki reports financial support was provided by Jane and Aatos Erkko Fundation. Laura T Wey reports financial support was provided by Novo Nordisk Foundation. Maria Ermakova reports financial support was provided by Australian Research Council. Maria Ermakova reports financial support was provided by Australian Academy of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Contributed Indexing: Keywords: ATP synthase; Arabidopsis; Chloroplast; Electrochromic shift; Photosynthesis; Proton motive force; Thioredoxin
Substance Nomenclature: 0 (Arabidopsis Proteins)
0 (PGR5 protein, Arabidopsis)
0 (Photosynthetic Reaction Center Complex Proteins)
EC 3.6.3.- (Chloroplast Proton-Translocating ATPases)
Entry Date(s): Date Created: 20260530 Date Completed: 20260909 Latest Revision: 20260909
Update Code: 20260910
DOI: 10.1016/j.bbabio.2026.149596
PMID: 42217716
Database: MEDLINE
FullText Text:
  Availability: 0
CustomLinks:
  – Url: https://www.doi.org/10.1016/j.bbabio.2026.149596?
    Name: ScienceDirect (all content) (s7799221)
    Category: fullText
    Text: View record from ScienceDirect
    MouseOverText: View record from ScienceDirect
  – Url: https://resolver.ebsco.com/c/fiv2js/result?sid=EBSCO:cmedm&genre=article&issn=18792650&ISBN=&volume=1867&issue=4&date=20261101&spage=149596&pages=149596&title=Biochimica et biophysica acta. Bioenergetics&atitle=PGR5%20is%20needed%20for%20regulation%20of%20ATP%20synthase%20in%20plant%20chloroplasts.&aulast=Nikkanen%20L&id=DOI:10.1016/j.bbabio.2026.149596
    Name: Full Text Finder (for New FTF UI) (ns324271)
    Category: fullText
    Text: Full Text Finder
    MouseOverText: Full Text Finder
Header DbId: cmedm
DbLabel: MEDLINE
An: 42217716
AccessLevel: 3
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: PGR5 is needed for regulation of ATP synthase in plant chloroplasts.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AU" term="%22Nikkanen+L%22">Nikkanen L</searchLink>; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland. Electronic address: lenikk@utu.fi.<br /><searchLink fieldCode="AU" term="%22Woodford+R%22">Woodford R</searchLink>; School of Biological Sciences, Monash University, Australia.<br /><searchLink fieldCode="AU" term="%22Andersin+E%22">Andersin E</searchLink>; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland.<br /><searchLink fieldCode="AU" term="%22Wey+LT%22">Wey LT</searchLink>; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland.<br /><searchLink fieldCode="AU" term="%22Ermakova+M%22">Ermakova M</searchLink>; School of Biological Sciences, Monash University, Australia.<br /><searchLink fieldCode="AU" term="%22Rintamäki+E%22">Rintamäki E</searchLink>; Molecular Plant Biology, Department of Life Technologies, University of Turku, Finland.
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22101731706%22">Biochimica et biophysica acta. Bioenergetics</searchLink> [Biochim Biophys Acta Bioenerg] 2026 Nov 01; Vol. 1867 (4), pp. 149596. <i>Date of Electronic Publication: </i>2026 May 29.
– Name: TypePub
  Label: Publication Type
  Group: TypPub
  Data: Journal Article
– Name: Language
  Label: Language
  Group: Lang
  Data: English
– Name: TitleSource
  Label: Journal Info
  Group: Src
  Data: <i>Publisher: </i><searchLink fieldCode="PB" term="%22Elsevier%22">Elsevier </searchLink><i>Country of Publication: </i>Netherlands <i>NLM ID: </i>101731706 <i>Publication Model: </i>Print-Electronic <i>Cited Medium: </i>Internet <i>ISSN: </i>1879-2650 (Electronic) <i>Linking ISSN: </i><searchLink fieldCode="IS" term="%2200052728%22">00052728 </searchLink><i>NLM ISO Abbreviation: </i>Biochim Biophys Acta Bioenerg <i>Subsets: </i>MEDLINE
– Name: PublisherInfo
  Label: Imprint Name(s)
  Group: PubInfo
  Data: <i>Original Publication</i>: Amsterdam : Elsevier
– Name: SubjectMESH
  Label: MeSH Terms
  Group: Su
  Data: <searchLink fieldCode="MM" term="%22Arabidopsis%22">Arabidopsis*</searchLink>/<searchLink fieldCode="MM" term="%22Arabidopsis+genetics%22">genetics</searchLink> <br /><searchLink fieldCode="MM" term="%22Arabidopsis%22">Arabidopsis*</searchLink>/<searchLink fieldCode="MM" term="%22Arabidopsis+enzymology%22">enzymology</searchLink> <br /><searchLink fieldCode="MM" term="%22Arabidopsis%22">Arabidopsis*</searchLink>/<searchLink fieldCode="MM" term="%22Arabidopsis+metabolism%22">metabolism</searchLink> <br /><searchLink fieldCode="MM" term="%22Arabidopsis+Proteins%22">Arabidopsis Proteins*</searchLink>/<searchLink fieldCode="MM" term="%22Arabidopsis+Proteins+metabolism%22">metabolism</searchLink> <br /><searchLink fieldCode="MM" term="%22Arabidopsis+Proteins%22">Arabidopsis Proteins*</searchLink>/<searchLink fieldCode="MM" term="%22Arabidopsis+Proteins+genetics%22">genetics</searchLink> <br /><searchLink fieldCode="MM" term="%22Chloroplasts%22">Chloroplasts*</searchLink>/<searchLink fieldCode="MM" term="%22Chloroplasts+enzymology%22">enzymology</searchLink> <br /><searchLink fieldCode="MM" term="%22Chloroplasts%22">Chloroplasts*</searchLink>/<searchLink fieldCode="MM" term="%22Chloroplasts+metabolism%22">metabolism</searchLink> <br /><searchLink fieldCode="MM" term="%22Chloroplasts%22">Chloroplasts*</searchLink>/<searchLink fieldCode="MM" term="%22Chloroplasts+genetics%22">genetics</searchLink> <br /><searchLink fieldCode="MM" term="%22Photosynthetic+Reaction+Center+Complex+Proteins%22">Photosynthetic Reaction Center Complex Proteins*</searchLink>/<searchLink fieldCode="MM" term="%22Photosynthetic+Reaction+Center+Complex+Proteins+metabolism%22">metabolism</searchLink> <br /><searchLink fieldCode="MM" term="%22Photosynthetic+Reaction+Center+Complex+Proteins%22">Photosynthetic Reaction Center Complex Proteins*</searchLink>/<searchLink fieldCode="MM" term="%22Photosynthetic+Reaction+Center+Complex+Proteins+genetics%22">genetics</searchLink> <br /><searchLink fieldCode="MM" term="%22Chloroplast+Proton-Translocating+ATPases%22">Chloroplast Proton-Translocating ATPases*</searchLink>/<searchLink fieldCode="MM" term="%22Chloroplast+Proton-Translocating+ATPases+metabolism%22">metabolism</searchLink><br /><searchLink fieldCode="MH" term="%22Light%22">Light</searchLink> ; <searchLink fieldCode="MH" term="%22Oxidation-Reduction%22">Oxidation-Reduction</searchLink> ; <searchLink fieldCode="MH" term="%22Proton-Motive+Force%22">Proton-Motive Force</searchLink> ; <searchLink fieldCode="MH" term="%22Electron+Transport%22">Electron Transport</searchLink> ; <searchLink fieldCode="MH" term="%22Photosynthesis%22">Photosynthesis</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Regulation of proton motive force (pmf) via ATP synthase activity is a critical mechanism by which photosynthetic organisms maintain redox homeostasis and control the activation and inactivation of photoprotective responses under fluctuating light conditions. Here, we used time-resolved electrochromic shift measurements to investigate pmf dynamics in the C<subscript>3</subscript> model plant Arabidopsis thaliana and the C<subscript>4</subscript> model grass Setaria viridis. Our results reveal that ATP synthase is dynamically regulated during light fluctuations, but in Arabidopsis this regulation could not be explained by the established light-induced reduction of the CF₁γ subunit by thioredoxins, suggesting alternative control mechanisms. The PROTON GRADIENT REGULATION 5 (PGR5) protein, previously proposed to facilitate cyclic electron transport (CET) in plants and algae, also has a potential role in regulation of ATP synthase. We therefore investigated pmf dynamics, cytochrome f redox changes, and linear and cyclic PSI electron transport rates in WT and pgr5 knock-out mutants and revealed that while PGR5 was not required for CET, it was needed for downregulating ATP synthase under high irradiance in both species. Furthermore, in Arabidopsis disturbance of thiol redox regulation by addition of N-ethylmaleimide resulted in downregulation of ATP synthase conductivity in WT but not in pgr5 mutants, and PGR5 interacted with CF₁γ in planta. We suggest that PGR5 functions as a conserved thiol redox state dependent inhibitor of chloroplast ATP synthase under high light, contributing to pmf retention and photoprotection.<br /> (Copyright © 2026. Published by Elsevier B.V.)
– Name: Abstract
  Label: Competing Interests
  Group: Ab
  Data: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Lauri Nikkanen reports financial support was provided by Research Council of Finland. Eevi Rintamäki reports financial support was provided by Research Council of Finland. Eevi Rintamäki reports financial support was provided by Jane and Aatos Erkko Fundation. Laura T Wey reports financial support was provided by Novo Nordisk Foundation. Maria Ermakova reports financial support was provided by Australian Research Council. Maria Ermakova reports financial support was provided by Australian Academy of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
– Name: SubjectMinor
  Label: Contributed Indexing
  Group:
  Data: <i>Keywords: </i>ATP synthase; Arabidopsis; Chloroplast; Electrochromic shift; Photosynthesis; Proton motive force; Thioredoxin
– Name: NumberCAS
  Label: Substance Nomenclature
  Group: ID
  Data: 0 (Arabidopsis Proteins)<br />0 (PGR5 protein, Arabidopsis)<br />0 (Photosynthetic Reaction Center Complex Proteins)<br />EC 3.6.3.- (Chloroplast Proton-Translocating ATPases)
– Name: DateEntry
  Label: Entry Date(s)
  Group: Date
  Data: <i>Date Created: </i>20260530 <i>Date Completed: </i>20260909 <i>Latest Revision: </i>20260909
– Name: DateUpdate
  Label: Update Code
  Group: Date
  Data: 20260910
– Name: DOI
  Label: DOI
  Group: ID
  Data: 10.1016/j.bbabio.2026.149596
– Name: AN
  Label: PMID
  Group: ID
  Data: 42217716
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=cmedm&AN=42217716
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1016/j.bbabio.2026.149596
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        StartPage: 149596
    Subjects:
      – SubjectFull: Light
        Type: general
      – SubjectFull: Oxidation-Reduction
        Type: general
      – SubjectFull: Proton-Motive Force
        Type: general
      – SubjectFull: Electron Transport
        Type: general
      – SubjectFull: Photosynthesis
        Type: general
      – SubjectFull: Arabidopsis genetics
        Type: general
      – SubjectFull: Arabidopsis enzymology
        Type: general
      – SubjectFull: Arabidopsis metabolism
        Type: general
      – SubjectFull: Arabidopsis Proteins metabolism
        Type: general
      – SubjectFull: Arabidopsis Proteins genetics
        Type: general
      – SubjectFull: Chloroplasts enzymology
        Type: general
      – SubjectFull: Chloroplasts metabolism
        Type: general
      – SubjectFull: Chloroplasts genetics
        Type: general
      – SubjectFull: Photosynthetic Reaction Center Complex Proteins metabolism
        Type: general
      – SubjectFull: Photosynthetic Reaction Center Complex Proteins genetics
        Type: general
      – SubjectFull: Chloroplast Proton-Translocating ATPases metabolism
        Type: general
    Titles:
      – TitleFull: PGR5 is needed for regulation of ATP synthase in plant chloroplasts.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Nikkanen L
      – PersonEntity:
          Name:
            NameFull: Woodford R
      – PersonEntity:
          Name:
            NameFull: Andersin E
      – PersonEntity:
          Name:
            NameFull: Wey LT
      – PersonEntity:
          Name:
            NameFull: Ermakova M
      – PersonEntity:
          Name:
            NameFull: Rintamäki E
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 11
              Text: 2026 Nov 01
              Type: published
              Y: 2026
          Identifiers:
            – Type: issn-electronic
              Value: 1879-2650
          Numbering:
            – Type: volume
              Value: 1867
            – Type: issue
              Value: 4
          Titles:
            – TitleFull: Biochimica et biophysica acta. Bioenergetics
              Type: main
ResultId 1