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dc.contributor.authorItakura, Alan Ken
dc.contributor.authorChan, Kher Xingen
dc.contributor.authorAtkinson, Nickyen
dc.contributor.authorPallesen, Leifen
dc.contributor.authorWang, Lianyongen
dc.contributor.authorReeves, Gregoryen
dc.contributor.authorPatena, Weronikaen
dc.contributor.authorCaspari, Oliveren
dc.contributor.authorRoth, Robynen
dc.contributor.authorGoodenough, Ursulaen
dc.contributor.authorMcCormick, Alistair Jen
dc.contributor.authorGriffiths, Howarden
dc.contributor.authorJonikas, Martin Cen
dc.date.accessioned2019-09-09T23:31:15Z
dc.date.available2019-09-09T23:31:15Z
dc.date.issued2019-09en
dc.identifier.issn0027-8424
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/296677
dc.description.abstractA phase-separated, liquid-like organelle called the pyrenoid mediates CO2 fixation in the chloroplasts of nearly all eukaryotic algae. While most algae have 1 pyrenoid per chloroplast, here we describe a mutant in the model alga Chlamydomonas that has on average 10 pyrenoids per chloroplast. Characterization of the mutant leads us to propose a model where multiple pyrenoids are favored by an increase in the surface area of the starch sheath that surrounds and binds to the liquid-like pyrenoid matrix. We find that the mutant’s phenotypes are due to disruption of a gene, which we call StArch Granules Abnormal 1 (SAGA1) because starch sheath granules, or plates, in mutants lacking SAGA1 are more elongated and thinner than those of wild type. SAGA1 contains a starch binding motif, suggesting that it may directly regulate starch sheath morphology. SAGA1 localizes to multiple puncta and streaks in the pyrenoid and physically interacts with the small and large subunits of the carbon-fixing enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase), a major component of the liquid-like pyrenoid matrix. Our findings suggest a biophysical mechanism by which starch sheath morphology affects pyrenoid number and CO2-concentrating mechanism function, advancing our understanding of the structure and function of this biogeochemically important organelle. More broadly, we propose that the number of phase-separated organelles can be regulated by imposing constraints on their surface area.
dc.format.mediumPrint-Electronicen
dc.languageengen
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectPlastidsen
dc.subjectChlamydomonasen
dc.subjectChlamydomonas reinhardtiien
dc.subjectCarbonen
dc.subjectStarchen
dc.subjectRibulose-Bisphosphate Carboxylaseen
dc.subjectCarrier Proteinsen
dc.subjectPlant Proteinsen
dc.subjectPhenotypeen
dc.subjectMutationen
dc.subjectCarbon Cycleen
dc.titleA Rubisco-binding protein is required for normal pyrenoid number and starch sheath morphology in Chlamydomonas reinhardtii.en
dc.typeArticle
prism.endingPage18454
prism.issueIdentifier37en
prism.publicationDate2019en
prism.publicationNameProceedings of the National Academy of Sciences of the United States of Americaen
prism.startingPage18445
prism.volume116en
dc.identifier.doi10.17863/CAM.43725
dcterms.dateAccepted2019-08-02en
rioxxterms.versionofrecord10.1073/pnas.1904587116en
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2019-09en
dc.contributor.orcidChan, Kher Xing [0000-0002-0236-6378]
dc.contributor.orcidCaspari, Oliver [0000-0001-8235-0503]
dc.contributor.orcidGriffiths, Howard [0000-0002-3009-6563]
dc.contributor.orcidJonikas, Martin C [0000-0002-9519-6055]
dc.identifier.eissn1091-6490
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idBBSRC (BB/I024518/1)
pubs.funder-project-idBBSRC (BB/M007693/1)


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Attribution-NonCommercial-NoDerivatives 4.0 International
Except where otherwise noted, this item's licence is described as Attribution-NonCommercial-NoDerivatives 4.0 International