Impact of sulfur starvation on cysteine biosynthesis in T-DNA mutants deficient for compartment-specific serine-acetyltransferase

• Published in: Amino acids Vol. 39; no. 4; pp. 1029 - 1042
• Main Authors: Krueger, Stephan, Donath, Andrea, Lopez-Martin, M. Carmen, Hoefgen, Rainer, Gotor, Cecilia, Hesse, Holger
• Format: Journal Article
• Language: English
• Published: Vienna Vienna : Springer Vienna 01-10-2010; Springer Vienna; Springer Nature B.V
• Subjects: Analytical Chemistry; Anion Transport Proteins - genetics; Anion Transport Proteins - metabolism; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Assimilation; Biochemical Engineering; Biochemistry; Biological Transport; Biomedical and Life Sciences; Biosynthesis; Carbon-Oxygen Lyases - metabolism; Chloroplasts - metabolism; CSC complex; Cysteine - biosynthesis; Cysteine Synthase - metabolism; Cytosol - enzymology; Cytosol - metabolism; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; Gene Expression Regulation, Plant; Gene Knockout Techniques; Life Sciences; Neurobiology; Non-aqueous fractionation; O-acetylserine-(thiol)-lyase; Original Article; Plants, Genetically Modified; Plasmids; Plastids - metabolism; Polymerase Chain Reaction; Proteins; Proteomics; RNA, Plant; SAT mutants; Seedlings - metabolism; Serine - analogs & derivatives; Serine - metabolism; serine O-acetyltransferase; Serine O-Acetyltransferase - genetics; Serine O-Acetyltransferase - metabolism; Sulfates - metabolism; Sulfhydryl Compounds - metabolism; Sulfur - metabolism; Serine acetyltransferase; SAT mutants; CSC complex; Non-aqueous fractionation; acetylserine-(thiol)-lyase
• ISSN: 0939-4451; 1438-2199
• DOI: 10.1007/s00726-010-0580-9

Sulfur plays a pivotal role in the cellular metabolism of many organisms. In plants, the uptake and assimilation of sulfate is strongly regulated at the transcriptional level. Regulatory factors are the demand of reduced sulfur in organic or non-organic form and the level of O-acetylserine (OAS), the carbon precursor for cysteine biosynthesis. In plants, cysteine is synthesized by action of the cysteine-synthase complex (CSC) containing serine acetyltransferase (SAT) and O-acetylserine-(thiol)-lyase (OASTL). Both enzymes are located in plastids, mitochondria and the cytosol. The function of the compartmentation of the CSC to regulate sulfate uptake and assimilation is still not clearly resolved. To address this question, we analyzed Arabidopsis thaliana mutants for the plastidic and cytosolic SAT isoenzymes under sulfur starvation conditions. In addition, subcellular metabolite analysis by non-aqueous fractionation revealed distinct changes in subcellular metabolite distribution upon short-term sulfur starvation. Metabolite and transcript analyses of SERAT1.1 and SERAT2.1 mutants [previously analyzed in Krueger et al. (Plant Cell Environ 32:349-367, 2009)] grown under sulfur starvation conditions indicate that both isoenzymes do not contribute directly to the transcriptional regulation of genes involved in sulfate uptake and assimilation. Here, we summarize the current knowledge about the regulation of cysteine biosynthesis and the contribution of the different compartments to this metabolic process. We relate hypotheses and views of the regulation of cysteine biosynthesis with our results of applying sulfur starvation to mutants impaired in compartment-specific cysteine biosynthetic enzymes.