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
Import Determinants of Organelle-Specific and Dual Targeting Peptides of Mitochondria and Chloroplasts in Arabidopsis thaliana
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
2014 (English)In: Molecular Plant, ISSN 1674-2052, Vol. 7, no 1, 121-136 p.Article in journal (Refereed) Published
Abstract [en]

Most of the mitochondrial and chloroplastic proteins are synthesized in the cytosol as precursor proteins carrying an N-terminal targeting peptide (TP) directing them specifically to a correct organelle. However, there is a group of proteins that are dually targeted to mitochondria and chloroplasts using an ambiguous N-terminal dual targeting peptide (dTP). Here, we have investigated pattern properties of import determinants of organelle-specific TPs and dTPs combining mathematical multivariate data analysis (MVDA) with in vitro organellar import studies. We have used large datasets of mitochondrial and chloroplastic proteins found in organellar proteomes as well as manually selected data sets of experimentally confirmed organelle-specific TPs and dTPs from Arabidopsis thaliana. Two classes of organelle-specific TPs could be distinguished by MVDA and potential patterns or periodicity in the amino acid sequence contributing to the separation were revealed. dTPs were found to have intermediate sequence features between the organelle-specific TPs. Interestingly, introducing positively charged residues to the dTPs showed clustering towards the mitochondrial TPs in silico and resulted in inhibition of chloroplast, but not mitochondrial import in in vitro organellar import studies. These findings suggest that positive charges in the N-terminal region of TPs may function as an 'avoidance signal' for the chloroplast import.

Place, publisher, year, edition, pages
2014. Vol. 7, no 1, 121-136 p.
Keyword [en]
dual targeting, ambiguous targeting signal, mitochondria, chloroplast, protein import, partial least square discriminant analysis, Arabidopsis thaliana
National Category
Biochemistry and Molecular Biology
Identifiers
URN: urn:nbn:se:su:diva-100099DOI: 10.1093/mp/sst148ISI: 000329254200010OAI: oai:DiVA.org:su-100099DiVA: diva2:692333
Note

AuthorCount:4;

Available from: 2014-01-30 Created: 2014-01-27 Last updated: 2014-10-29Bibliographically approved
In thesis
1. Dual targeting of proteins to mitochondria and chloroplasts: Characterization of dual targeting peptides and their interaction with organellar receptors
Open this publication in new window or tab >>Dual targeting of proteins to mitochondria and chloroplasts: Characterization of dual targeting peptides and their interaction with organellar receptors
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Most mitochondrial and chloroplastic proteins are synthesized in the cytosol as precursor proteins with an N-terminal targeting peptide (TP), which directs them to the correct organelle. There is also a group of proteins that are dual targeted to mitochondria and chloroplasts using an ambiguous N-terminal dual targeting peptide (dTP). The aim of this thesis was to characterize dTPs with respect to physicochemical features, sequence patterns, structural properties and interaction with the mitochondrial and chloroplastic receptors.

We have used different statistical methods, including a multivariate data analysis (MVDA) to analyse all available dTPs and compare them to organelle-specific TPs of proteome-identified mitochondrial and chloroplastic proteins from Arabidopsis thaliana. The overall amino acid sequence patterns of dTPs were intermediate between mitochondrial targeting peptides (mTPs) and chloroplastic targeting peptides (cTPs) but the greatest differences in amino acid composition were found within the very N-terminal region of dTPs, where especially arginines are highly overrepresented in relation to cTPs. Interestingly, introducing arginines to the dTPs showed clustering towards the mTPs in silico and resulted in inhibition of chloroplast import in vitro, suggesting that positive charges in the N-terminal region of TPs may function as an 'avoidance signal' for chloroplast import.

Studies with the dTP of threonyl-tRNA synthetase (ThrRS-dTP) revealed that 60 amino acids were required to confer dual targeting. The purified ThrRS-dTP(2-60) inhibited import of organelle-specific proteins, providing evidence that dual and organelle-specific proteins use the same organellar import pathways. CD spectra indicated that ThrRS-dTP(2-60) has the propensity to form a-helical structure in membrane mimetic environments. Further, NMR investigations of interaction profiles of ThrRS-dTP(2-60) with the mitochondrial Tom20 and the chloroplastic Toc34 receptor demonstrated that the mode of the recognition of a dual targeting peptide by mitochondrial and chloroplastic receptors is different. Our studies provide thorough characterization of dTPs and present for the first time dTP-organellar receptor interactions on the molecular level.

Place, publisher, year, edition, pages
Stockholm: Department of Biochemistry and Biophysics, Stockholm University, 2014. 76 p.
National Category
Biochemistry and Molecular Biology
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-108471 (URN)978-91-7649-027-3 (ISBN)
Public defence
2014-12-12, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.

Available from: 2014-11-20 Created: 2014-10-28 Last updated: 2014-12-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Spånning, ErikaGlaser, Elzbieta
By organisation
Department of Biochemistry and Biophysics
Biochemistry and Molecular Biology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 104 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