Tags

Type your tag names separated by a space and hit enter

Mitochondrial serine acetyltransferase functions as a pacemaker of cysteine synthesis in plant cells.
Plant Physiol 2008; 148(2):1055-67PP

Abstract

Cysteine (Cys) synthesis in plants is carried out by two sequential reactions catalyzed by the rate-limiting enzyme serine acetyltransferase (SAT) and excess amounts of O-acetylserine(thiol)lyase. Why these reactions occur in plastids, mitochondria, and cytosol of plants remained unclear. Expression of artificial microRNA (amiRNA) against Sat3 encoding mitochondrial SAT3 in transgenic Arabidopsis (Arabidopsis thaliana) plants demonstrates that mitochondria are the most important compartment for the synthesis of O-acetylserine (OAS), the precursor of Cys. Reduction of RNA levels, protein contents, SAT enzymatic activity, and phenotype strongly correlate in independent amiSAT3 lines and cause significantly retarded growth. The expression of the other four Sat genes in the Arabidopsis genome are not affected by amiRNA-SAT3 according to quantitative real-time polymerase chain reaction and microarray analyses. Application of radiolabeled serine to leaf pieces revealed severely reduced incorporation rates into Cys and even more so into glutathione. Accordingly, steady-state levels of OAS are 4-fold reduced. Decrease of sulfate reduction-related genes is accompanied by an accumulation of sulfate in amiSAT3 lines. These results unequivocally show that mitochondria provide the bulk of OAS in the plant cell and are the likely site of flux regulation. Together with recent data, the cytosol appears to be a major site of Cys synthesis, while plastids contribute reduced sulfur as sulfide. Thus, Cys synthesis in plants is significantly different from that in nonphotosynthetic eukaryotes at the cellular level.

Authors+Show Affiliations

Heidelberg Institute for Plant Sciences, Heidelberg University, Heidelberg, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

18753283

Citation

Haas, Florian H., et al. "Mitochondrial Serine Acetyltransferase Functions as a Pacemaker of Cysteine Synthesis in Plant Cells." Plant Physiology, vol. 148, no. 2, 2008, pp. 1055-67.
Haas FH, Heeg C, Queiroz R, et al. Mitochondrial serine acetyltransferase functions as a pacemaker of cysteine synthesis in plant cells. Plant Physiol. 2008;148(2):1055-67.
Haas, F. H., Heeg, C., Queiroz, R., Bauer, A., Wirtz, M., & Hell, R. (2008). Mitochondrial serine acetyltransferase functions as a pacemaker of cysteine synthesis in plant cells. Plant Physiology, 148(2), pp. 1055-67. doi:10.1104/pp.108.125237.
Haas FH, et al. Mitochondrial Serine Acetyltransferase Functions as a Pacemaker of Cysteine Synthesis in Plant Cells. Plant Physiol. 2008;148(2):1055-67. PubMed PMID: 18753283.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mitochondrial serine acetyltransferase functions as a pacemaker of cysteine synthesis in plant cells. AU - Haas,Florian H, AU - Heeg,Corinna, AU - Queiroz,Rafael, AU - Bauer,Andrea, AU - Wirtz,Markus, AU - Hell,Rüdiger, Y1 - 2008/08/27/ PY - 2008/8/30/pubmed PY - 2008/12/17/medline PY - 2008/8/30/entrez SP - 1055 EP - 67 JF - Plant physiology JO - Plant Physiol. VL - 148 IS - 2 N2 - Cysteine (Cys) synthesis in plants is carried out by two sequential reactions catalyzed by the rate-limiting enzyme serine acetyltransferase (SAT) and excess amounts of O-acetylserine(thiol)lyase. Why these reactions occur in plastids, mitochondria, and cytosol of plants remained unclear. Expression of artificial microRNA (amiRNA) against Sat3 encoding mitochondrial SAT3 in transgenic Arabidopsis (Arabidopsis thaliana) plants demonstrates that mitochondria are the most important compartment for the synthesis of O-acetylserine (OAS), the precursor of Cys. Reduction of RNA levels, protein contents, SAT enzymatic activity, and phenotype strongly correlate in independent amiSAT3 lines and cause significantly retarded growth. The expression of the other four Sat genes in the Arabidopsis genome are not affected by amiRNA-SAT3 according to quantitative real-time polymerase chain reaction and microarray analyses. Application of radiolabeled serine to leaf pieces revealed severely reduced incorporation rates into Cys and even more so into glutathione. Accordingly, steady-state levels of OAS are 4-fold reduced. Decrease of sulfate reduction-related genes is accompanied by an accumulation of sulfate in amiSAT3 lines. These results unequivocally show that mitochondria provide the bulk of OAS in the plant cell and are the likely site of flux regulation. Together with recent data, the cytosol appears to be a major site of Cys synthesis, while plastids contribute reduced sulfur as sulfide. Thus, Cys synthesis in plants is significantly different from that in nonphotosynthetic eukaryotes at the cellular level. SN - 0032-0889 UR - https://www.unboundmedicine.com/medline/citation/18753283/Mitochondrial_serine_acetyltransferase_functions_as_a_pacemaker_of_cysteine_synthesis_in_plant_cells_ L2 - http://www.plantphysiol.org/cgi/pmidlookup?view=long&pmid=18753283 DB - PRIME DP - Unbound Medicine ER -