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Mitochondrial cysteine synthase complex regulates O-acetylserine biosynthesis in plants.
J Biol Chem 2012; 287(33):27941-7JB

Abstract

Cysteine synthesis is catalyzed by serine acetyltransferase (SAT) and O-acetylserine (thiol) lyase (OAS-TL) in the cytosol, plastids, and mitochondria of plants. Biochemical analyses of recombinant plant SAT and OAS-TL indicate that the reversible association of the proteins in the cysteine synthase complex (CSC) controls cellular sulfur homeostasis. However, the relevance of CSC formation in each compartment for flux control of cysteine synthesis remains controversial. Here, we demonstrate the interaction between mitochondrial SAT3 and OAS-TL C in planta by FRET and establish the role of the mitochondrial CSC in the regulation of cysteine synthesis. NMR spectroscopy of isolated mitochondria from WT, serat2;2, and oastl-C plants showed the SAT-dependent export of OAS. The presence of cysteine resulted in reduced OAS export in mitochondria of oastl-C mutants but not in WT mitochondria. This is in agreement with the stronger in vitro feedback inhibition of free SAT by cysteine compared with CSC-bound SAT and explains the high OAS export rate of WT mitochondria in the presence of cysteine. The predominant role of mitochondrial OAS synthesis was validated in planta by feeding [(3)H]serine to the WT and loss-of-function mutants for OAS-TLs in the cytosol, plastids, and mitochondria. On the basis of these results, we propose a new model in which the mitochondrial CSC acts as a sensor that regulates the level of SAT activity in response to sulfur supply and cysteine demand.

Authors+Show Affiliations

Centre for Organismal Studies (COS) Heidelberg, University of Heidelberg, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo 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

22730323

Citation

Wirtz, Markus, et al. "Mitochondrial Cysteine Synthase Complex Regulates O-acetylserine Biosynthesis in Plants." The Journal of Biological Chemistry, vol. 287, no. 33, 2012, pp. 27941-7.
Wirtz M, Beard KF, Lee CP, et al. Mitochondrial cysteine synthase complex regulates O-acetylserine biosynthesis in plants. J Biol Chem. 2012;287(33):27941-7.
Wirtz, M., Beard, K. F., Lee, C. P., Boltz, A., Schwarzländer, M., Fuchs, C., ... Hell, R. (2012). Mitochondrial cysteine synthase complex regulates O-acetylserine biosynthesis in plants. The Journal of Biological Chemistry, 287(33), pp. 27941-7. doi:10.1074/jbc.M112.372656.
Wirtz M, et al. Mitochondrial Cysteine Synthase Complex Regulates O-acetylserine Biosynthesis in Plants. J Biol Chem. 2012 Aug 10;287(33):27941-7. PubMed PMID: 22730323.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mitochondrial cysteine synthase complex regulates O-acetylserine biosynthesis in plants. AU - Wirtz,Markus, AU - Beard,Katherine F M, AU - Lee,Chun Pong, AU - Boltz,Achim, AU - Schwarzländer,Markus, AU - Fuchs,Christopher, AU - Meyer,Andreas J, AU - Heeg,Corinna, AU - Sweetlove,Lee J, AU - Ratcliffe,R George, AU - Hell,Rüdiger, Y1 - 2012/06/22/ PY - 2012/6/26/entrez PY - 2012/6/26/pubmed PY - 2012/11/6/medline SP - 27941 EP - 7 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 287 IS - 33 N2 - Cysteine synthesis is catalyzed by serine acetyltransferase (SAT) and O-acetylserine (thiol) lyase (OAS-TL) in the cytosol, plastids, and mitochondria of plants. Biochemical analyses of recombinant plant SAT and OAS-TL indicate that the reversible association of the proteins in the cysteine synthase complex (CSC) controls cellular sulfur homeostasis. However, the relevance of CSC formation in each compartment for flux control of cysteine synthesis remains controversial. Here, we demonstrate the interaction between mitochondrial SAT3 and OAS-TL C in planta by FRET and establish the role of the mitochondrial CSC in the regulation of cysteine synthesis. NMR spectroscopy of isolated mitochondria from WT, serat2;2, and oastl-C plants showed the SAT-dependent export of OAS. The presence of cysteine resulted in reduced OAS export in mitochondria of oastl-C mutants but not in WT mitochondria. This is in agreement with the stronger in vitro feedback inhibition of free SAT by cysteine compared with CSC-bound SAT and explains the high OAS export rate of WT mitochondria in the presence of cysteine. The predominant role of mitochondrial OAS synthesis was validated in planta by feeding [(3)H]serine to the WT and loss-of-function mutants for OAS-TLs in the cytosol, plastids, and mitochondria. On the basis of these results, we propose a new model in which the mitochondrial CSC acts as a sensor that regulates the level of SAT activity in response to sulfur supply and cysteine demand. SN - 1083-351X UR - https://www.unboundmedicine.com/medline/citation/22730323/Mitochondrial_cysteine_synthase_complex_regulates_O_acetylserine_biosynthesis_in_plants_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=22730323 DB - PRIME DP - Unbound Medicine ER -