umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Characterization of auxiliary membrane proteins in the chloroplast of Arabidopsis thaliana
Umeå University, Faculty of Science and Technology, Department of Chemistry.ORCID iD: 0000-0001-6970-7221
2016 (English)Doctoral thesis, comprehensive summary (Other academic)Alternative title
Karakterisering av membran-lokaliserade hjälparproteiner i kloroplasten hos växten backtrav (Swedish)
Abstract [en]

In nature, sessile plants have to adapt to their environment and to the never ending changes they are exposed to. They do so mainly by proteomic and metabolomic changes. In all cells, there are complex networks of auxiliary proteins that are responsible for quality control of all the cell's proteins. The auxiliary proteins are divided into chaperones and proteases, and these are further separated into different groups. Chaperones help other proteins in terms of stability and folding. In order for a protein to achieve its function, the three-dimensional structure has to be precise. A protease is a helper protein that is able to break peptide bonds in a process termed proteolysis. Chaperones and proteases can work independently, but sometimes the chaperone unfolds the substrate of the protease to ensure full degradation of the protein. In some cases, the chaperone and the protease functions are combined in one protein.

All proteins studied within this thesis are localized in the chloroplast, the organelle that originated from cyanobacteria, in which plants and algae convert the energy from sunlight into carbohydrates in the process called photosynthesis. Molecular oxygen is released as a by-product, and carbon dioxide is consumed. Photosystem II (PSII), one of the major protein complexes involved in photosynthesis, consists of more than 30 protein subunits, where around half of them are termed low molecular weight (LMW) proteins with a molecular size less than 10 kDa. In this thesis, data identifying one PSII LMW protein, PsbY, as a chaperone for the PSII subcomplex Cytochrome b559 are presented. In the absence of PsbY, Arabidopsis plants were more sensitive to photoinhibition, and the protective circular electron transport around PSII is completely blocked.

Data on members of the Filamentation temperature sensitive protein H (FtsH) protease family are also discussed, with a focus on FtsH11 and FtsHi1-i5. Members of the FtsH protease family carry a protease domain and a chaperone domain. Our data show that FtsH11 has an influence on the structure and function of chloroplasts of Arabidopsis plants grown under continuous light along with protein import into the same. FtsHi1-5 are five members with mutations within the proteolytic motif, most probably rendering them proteolytically inactive, hence they are referred to as ''inactive FtsH proteases''. Knock-out plants of the inactive members are embryo lethal, and knock-down plants grow slower than wild type, probably because of an affected level of plastid proteins at the translational level.

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2016. , 52 p.
Keyword [en]
Arabidopsis, chaperone, chloroplast, Cytochrome b559, FtsH, membrane proteins, photosynthesis, Photosystem II, protease, PsbY.
Keyword [sv]
Arabidopsis, chaperone, Cytochrome b559, fotosyntes, fotosystem II, FtsH, kloroplast, membranprotein, proteas, PsbY.
National Category
Biochemistry and Molecular Biology Plant Biotechnology
Research subject
Biochemistry
Identifiers
URN: urn:nbn:se:umu:diva-125819ISBN: 978-91-7601-480-6 (print)OAI: oai:DiVA.org:umu-125819DiVA: diva2:972686
Public defence
2016-10-10, N450, Naturvetarhuset, Umeå, 10:00 (English)
Opponent
Supervisors
Funder
Swedish Energy Agency, 2012-005889​
Note

Avhandlingen är skriven på engelska, men innehåller också en enkel sammanfattning på svenska. 

Available from: 2016-09-26 Created: 2016-09-19 Last updated: 2016-09-23Bibliographically approved
List of papers
1. The PsbY protein of Arabidopsis Photosystem II is important for the redox control of cytochrome b559
Open this publication in new window or tab >>The PsbY protein of Arabidopsis Photosystem II is important for the redox control of cytochrome b559
Show others...
2016 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1857, no 9, 1524-1533 p.Article in journal (Refereed) Published
Abstract [en]

Abstract Photosystem II is a protein complex embedded in the thylakoid membrane of photosynthetic organisms and performs the light driven water oxidation into electrons and molecular oxygen that initiate the photosynthetic process. This important complex is composed of more than two dozen of intrinsic and peripheral subunits, of those half are low molecular mass proteins. PsbY is one of those low molecular mass proteins; this 4.7–4.9 kDa intrinsic protein seems not to bind any cofactors. Based on structural data from cyanobacterial and red algal Photosystem II PsbY is located closely or in direct contact with cytochrome b559. Cytb559 consists of two protein subunits (PsbE and PsbF) ligating a heme-group in-between them. While the exact function of this component in Photosystem II has not yet been clarified, a crucial role for assembly and photo-protection in prokaryotic complexes has been suggested. One unique feature of Cytb559 is its redox-heterogeneity, forming high, medium and low potential, however, neither origin nor mechanism are known. To reveal the function of PsbY within Photosystem II of Arabidopsis we have analysed PsbY knock-out plants and compared them to wild type and to complemented mutant lines. We show that in the absence of PsbY protein Cytb559 is only present in its oxidized, low potential form and plants depleted of PsbY were found to be more susceptible to photoinhibition.

Keyword
Photosystem II, Thylakoid membrane, PsbY protein, Cytochrome b559
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-124444 (URN)10.1016/j.bbabio.2016.05.004 (DOI)000382590400019 ()27220875 (PubMedID)
Available from: 2016-08-11 Created: 2016-08-11 Last updated: 2017-11-28Bibliographically approved
2. Deletion of FtsH11 protease has impact on chloroplast structure and function in Arabidopsis thaliana when grown under continuous light
Open this publication in new window or tab >>Deletion of FtsH11 protease has impact on chloroplast structure and function in Arabidopsis thaliana when grown under continuous light
Show others...
2016 (English)In: Plant, Cell and Environment, ISSN 0140-7791, E-ISSN 1365-3040, Vol. 39, no 11, 2530-2544 p.Article in journal (Refereed) Published
Abstract [en]

The membrane-integrated metallo-protease FtsH11 of Arabidopsis thaliana is proposed to be dual targeted to mitochondria and chloroplasts. A bleached phenotype was observed in ftsh11 grown at long days or continuous light, pointing to disturbances in the chloroplast. Within the chloroplast FtsH11 was found to be located exclusively in the envelope. Two chloroplast-located proteins of unknown function (Tic22-like protein and YGGT-A) showed significantly higher abundance in envelope membranes and intact chloroplasts of ftsH11, and therefore qualify as potential substrates for the FtsH11 protease. No proteomic changes were observed in the mitochondria of 6 weeks old ftsH11 compared to wild type and FtsH11 was not immunodetected in these organelles. The abundance of plastidic proteins, especially of photosynthetic proteins, was altered even during standard growth conditions in total leaves of ftsh11. At continuous light the amount of PSI decreased relative to PSII, accompanied by a drastic change of the chloroplast morphology and a drop of NPQ. FtsH11 is crucial for chloroplast structure and function during growth in prolonged photoperiod.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
Keyword
envelope, light acclimation
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-124441 (URN)10.1111/pce.12808 (DOI)000385842400015 ()27479913 (PubMedID)
Available from: 2016-08-11 Created: 2016-08-11 Last updated: 2017-11-28Bibliographically approved
3. Characterization of the plastid-localized inactive FtsHis of Arabidopsis thaliana
Open this publication in new window or tab >>Characterization of the plastid-localized inactive FtsHis of Arabidopsis thaliana
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In the genome of Arabidopsis thaliana five genes encode members of the FtsH (Filamentation temperature sensitive protein H) protease family with mutations or deletions in their proteolytic site. Despite of not being active proteases these so called FtsHi (i for inactive) enzymes still seem to be highly important for plant development. All five enzymes have been localized within the plant chloroplast, most of them seem to be inserted in the chloroplast envelope. As homozygous ftshi mutants are seed lethal, here we compared different heterozygous ftshi mutants with respect to their growth at various light periods and at semi-natural growth conditions in the field. Their photosynthetic efficiency was evaluated by pulse-amplitude modulated fluorescence and the composition of their photosynthetic complexes was analysed by native polyacrylamide gel electrophoresis. Co-expression analyses were performed to find clues about the function of the five FtsHi inactive proteases.

Keyword
Arabidopsis, chloroplast, inactive FtsH protease
National Category
Biochemistry and Molecular Biology Plant Biotechnology
Research subject
Biochemistry
Identifiers
urn:nbn:se:umu:diva-125815 (URN)
Funder
Swedish Energy Agency, 2012-005889​
Available from: 2016-09-21 Created: 2016-09-19 Last updated: 2016-09-23
4. Functional Update of the Auxiliary Proteins PsbW, PsbY, HCF136, PsbN, TerC and ALB3 in Maintenance and Assembly of PSII
Open this publication in new window or tab >>Functional Update of the Auxiliary Proteins PsbW, PsbY, HCF136, PsbN, TerC and ALB3 in Maintenance and Assembly of PSII
Show others...
2016 (English)In: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 7, 423Article in journal (Refereed) Published
Abstract [en]

Assembly of Photosystem (PS) II in plants has turned out to be a highly complex process which, at least in part, occurs in a sequential order and requires many more auxiliary proteins than subunits present in the complex. Owing to the high evolutionary conservation of the subunit composition and the three-dimensional structure of the PSII complex, most plant factors involved in the biogenesis of PSII originated from cyanobacteria and only rarely evolved de novo. Furthermore, in chloroplasts the initial assembly steps occur in the non-appressed stroma lamellae, whereas the final assembly including the attachment of the major LHCII antenna proteins takes place in the grana regions. The stroma lamellae are also the place where part of PSII repair occurs, which very likely also involves assembly factors. In cyanobacteria initial PSII assembly also occurs in the thylakoid membrane, in so-called thylakoid centers, which are in contact with the plasma membrane. Here, we provide an update on the structures, localisations, topologies, functions, expression and interactions of the low molecular mass PSII subunits PsbY, PsbW and the auxiliary factors HCF136, PsbN, TerC and ALB3, assisting in PSII complex assembly and protein insertion into the thylakoid membrane.

Keyword
PSII photosystem II, cytochrome b559, assembly, low molecular mass proteins, Arabidopsis
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-120622 (URN)10.3389/fpls.2016.00423 (DOI)000373599400001 ()27092151 (PubMedID)
Available from: 2016-08-16 Created: 2016-05-18 Last updated: 2017-11-28Bibliographically approved

Open Access in DiVA

fulltext(4635 kB)122 downloads
File information
File name FULLTEXT01.pdfFile size 4635 kBChecksum SHA-512
bf6951fafc4f90dea78022552b1f93cd2e7f38a9c58a4612a5c0799f76b9239243a9f6fb0175bff8cfce7c3c03b0348aadc3899afaf8caef612fc708caf1523d
Type fulltextMimetype application/pdf
spikblad(67 kB)31 downloads
File information
File name SPIKBLAD01.pdfFile size 67 kBChecksum SHA-512
04ee6b9200b51173b49e7aba9e5c5b08201bdecd3325ffcfa2d99115849c3c3a3f982c76e19dd59d12bdae3f92aa013c37790d3c647d8d6c7e59b1ea8f0850e5
Type spikbladMimetype application/pdf
cover(408 kB)21 downloads
File information
File name COVER01.pdfFile size 408 kBChecksum SHA-512
16be02869424fdfd70f32d7787b0d53224d9230ccd1bb01b3575b02c7d9ee9f90358b65fadac97601788424c187361c36461b515d2c6a93dd64129de37f12e51
Type coverMimetype application/pdf

Search in DiVA

By author/editor
von Sydow, Lotta
By organisation
Department of Chemistry
Biochemistry and Molecular BiologyPlant Biotechnology

Search outside of DiVA

GoogleGoogle Scholar
Total: 122 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1209 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf