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Enzyme activities and subcellular localization of members of the Arabidopsis glutathione transferase superfamily

Dixon, D.P.; Hawkins, T.; Hussey, P.J.; Edwards, R.

Enzyme activities and subcellular localization of members of the Arabidopsis glutathione transferase superfamily Thumbnail


Authors

D.P. Dixon

R. Edwards



Abstract

Enzyme screens with Strep-tagged recombinant proteins and expression studies with the respective green fluorescent protein (GFP) fusions have been employed to examine the functional activities and subcellular localization of members of the Arabidopsis glutathione transferase (GST) superfamily. Fifty-one of 54 GST family members were transcribed and 41 found to express as functional glutathione-dependent enzymes in Escherichia coli. Functional redundancy was observed and in particular three theta (T) class GSTs showed conserved activities as hydroperoxide-reducing glutathione peroxidases (GPOXs). When expressed in tobacco as GFP fusions, all three GSTTs localized to the peroxisome, where their GPOX activity could prevent membrane damage arising from fatty acid oxidation. Through alternative splicing, two of these GSTTs form fusions with Myb transcription factor-like domains. Examination of one of these variants showed discrete localization within the nucleus, possibly serving a role in reducing nucleic acid hydroperoxides or in signalling. Based on this unexpected differential sub-cellular localization, 15 other GST family members were expressed as GFP fusions in tobacco. Most accumulated in the cytosol, but GSTU12 localized to the nucleus, a family member resembling a bacterial tetrachlorohydroquinone dehalogenase selectively associated with the plasma membrane, and a lambda GSTL2 was partially directed to the peroxisome after removal of a putative chloroplast transit peptide. Based on the results obtained with the GSTTs, it was concluded that these proteins can exert identical protective functions in differing subcellular compartments.

Journal Article Type Article
Publication Date Mar 1, 2009
Deposit Date Mar 31, 2009
Publicly Available Date Apr 8, 2009
Journal Journal of Experimental Botany
Print ISSN 0022-0957
Electronic ISSN 1460-2431
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 60
Issue 4
Pages 1207-1218
DOI https://doi.org/10.1093/jxb/ern365
Keywords Alternative splicing, Confocal microscopy, Glutathione peroxidase, Green fluorescent protein, Lipid hydroperoxides, Nicotiana benthamiana, Peroxisome, Strep tag.
Public URL https://durham-repository.worktribe.com/output/1560701

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Copyright Statement
© 2009 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)






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