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Dominant-negative modification reveals the regulatory function of the multimeric cysteine synthase protein complex in transgenic tobacco.
Plant Cell 2007; 19(2):625-39PC

Abstract

Cys synthesis in plants constitutes the entry of reduced sulfur from assimilatory sulfate reduction into metabolism. The catalyzing enzymes serine acetyltransferase (SAT) and O-acetylserine (OAS) thiol lyase (OAS-TL) reversibly form the heterooligomeric Cys synthase complex (CSC). Dominant-negative mutation of the CSC showed the crucial function for the regulation of Cys biosynthesis in vivo. An Arabidopsis thaliana SAT was overexpressed in the cytosol of transgenic tobacco (Nicotiana tabacum) plants in either enzymatically active or inactive forms that were both shown to interact efficiently with endogenous tobacco OAS-TL proteins. Active SAT expression resulted in a 40-fold increase in SAT activity and strong increases in the reaction intermediate OAS as well as Cys, glutathione, Met, and total sulfur contents. However, inactive SAT expression produced much greater enhancing effects, including 30-fold increased Cys levels, attributable, apparently, to the competition of inactive transgenic SAT with endogenous tobacco SAT for binding to OAS-TL. Expression levels of tobacco SAT and OAS-TL remained unaffected. Flux control coefficients suggested that the accumulation of OAS and Cys in both types of transgenic plants was accomplished by different mechanisms. These data provide evidence that the CSC and its subcellular compartmentation play a crucial role in the control of Cys biosynthesis, a unique function for a plant metabolic protein complex.

Authors+Show Affiliations

Heidelberg Institute of Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17293569

Citation

Wirtz, Markus, and Rüdiger Hell. "Dominant-negative Modification Reveals the Regulatory Function of the Multimeric Cysteine Synthase Protein Complex in Transgenic Tobacco." The Plant Cell, vol. 19, no. 2, 2007, pp. 625-39.
Wirtz M, Hell R. Dominant-negative modification reveals the regulatory function of the multimeric cysteine synthase protein complex in transgenic tobacco. Plant Cell. 2007;19(2):625-39.
Wirtz, M., & Hell, R. (2007). Dominant-negative modification reveals the regulatory function of the multimeric cysteine synthase protein complex in transgenic tobacco. The Plant Cell, 19(2), pp. 625-39.
Wirtz M, Hell R. Dominant-negative Modification Reveals the Regulatory Function of the Multimeric Cysteine Synthase Protein Complex in Transgenic Tobacco. Plant Cell. 2007;19(2):625-39. PubMed PMID: 17293569.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dominant-negative modification reveals the regulatory function of the multimeric cysteine synthase protein complex in transgenic tobacco. AU - Wirtz,Markus, AU - Hell,Rüdiger, Y1 - 2007/02/09/ PY - 2007/2/13/pubmed PY - 2007/7/28/medline PY - 2007/2/13/entrez SP - 625 EP - 39 JF - The Plant cell JO - Plant Cell VL - 19 IS - 2 N2 - Cys synthesis in plants constitutes the entry of reduced sulfur from assimilatory sulfate reduction into metabolism. The catalyzing enzymes serine acetyltransferase (SAT) and O-acetylserine (OAS) thiol lyase (OAS-TL) reversibly form the heterooligomeric Cys synthase complex (CSC). Dominant-negative mutation of the CSC showed the crucial function for the regulation of Cys biosynthesis in vivo. An Arabidopsis thaliana SAT was overexpressed in the cytosol of transgenic tobacco (Nicotiana tabacum) plants in either enzymatically active or inactive forms that were both shown to interact efficiently with endogenous tobacco OAS-TL proteins. Active SAT expression resulted in a 40-fold increase in SAT activity and strong increases in the reaction intermediate OAS as well as Cys, glutathione, Met, and total sulfur contents. However, inactive SAT expression produced much greater enhancing effects, including 30-fold increased Cys levels, attributable, apparently, to the competition of inactive transgenic SAT with endogenous tobacco SAT for binding to OAS-TL. Expression levels of tobacco SAT and OAS-TL remained unaffected. Flux control coefficients suggested that the accumulation of OAS and Cys in both types of transgenic plants was accomplished by different mechanisms. These data provide evidence that the CSC and its subcellular compartmentation play a crucial role in the control of Cys biosynthesis, a unique function for a plant metabolic protein complex. SN - 1040-4651 UR - https://www.unboundmedicine.com/medline/citation/17293569/Dominant_negative_modification_reveals_the_regulatory_function_of_the_multimeric_cysteine_synthase_protein_complex_in_transgenic_tobacco_ L2 - http://www.plantcell.org/cgi/pmidlookup?view=long&pmid=17293569 DB - PRIME DP - Unbound Medicine ER -