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

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

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.

Citation

Dixon, D., Hawkins, T., Hussey, P., & Edwards, R. (2009). Enzyme activities and subcellular localization of members of the Arabidopsis glutathione transferase superfamily. Journal of Experimental Botany, 60(4), 1207-1218. https://doi.org/10.1093/jxb/ern365

• 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