Search results for "Glycera"
showing 10 items of 57 documents
PGDH family genes differentially affect Arabidopsis tolerance to salt stress
2019
The first step in the Phosphorylated Pathway of serine (Ser) Biosynthesis (PPSB) is catalyzed by the enzyme Phosphoglycerate Dehydrogenase (PGDH), coded in Arabidopsis thaliana by three genes. Gene expression analysis indicated that PGDH1 and PGDH2 were induced, while PGDH3 was repressed, by salt-stress. Accordingly, PGDH3 overexpressing plants (Oex PGDH3) were more sensitive to salinity than wild type plants (WT), while plants overexpressing PGDH1 (Oex PGDH1) performed better than WT under salinity conditions. Oex PGDH1 lines displayed lower levels of the salt-stress markers proline and raffinose in roots than WT under salt-stress conditions. Besides, the ratio of oxidized glutathione (GSS…
Overexpression of the triose phosphate translocator (TPT) complements the abnormal metabolism and development of plastidial glycolytic glyceraldehyde…
2017
The presence of two glycolytic pathways working in parallel in plastids and cytosol has complicated the understanding of this essential process in plant cells, especially the integration of the plastidial pathway into the metabolism of heterotrophic and autotrophic organs. It is assumed that this integration is achieved by transport systems, which exchange glycolytic intermediates across plastidial membranes. However, it is unknown whether plastidial and cytosolic pools of 3-phosphoglycerate (3-PGA) can equilibrate in non-photosynthetic tissues. To resolve this question, we employed Arabidopsis mutants of the plastidial glycolytic isoforms of glyceraldehyde-3-phosphate dehydrogenase (GAPCp)…
Phosphoglycerate dehydrogenase genes differentially affect Arabidopsis metabolism and development.
2021
[EN] Unlike animals, plants possess diverse L-serine (Ser) biosynthetic pathways. One of them, the Phosphorylated Pathway of Serine Biosynthesis (PPSB) has been recently described as essential for embryo, pollen and root development, and required for ammonium and sulfur assimilation. The first and rate limiting step of PPSB is the reaction catalyzed by the enzyme phosphoglycerate dehydrogenase (PGDH). In Arabidopsis, the PGDH family consists of three genes, PGDH1, PGDH2 and PGDH3. PGDH1 is characterized as being the essential gene of the family. However, the biological significance of PGDH2 and PGDH3 remains unknown. In this manuscript, we have functionally characterized PGDH2 and PGDH3. Ph…
The specific role of plastidial glycolysis in photosynthetic and heterotrophic cells under scrutiny through the study of glyceraldehyde-3-phosphate d…
2016
The cellular compartmentalization of metabolic processes is an important feature in plants where the same pathways could be simultaneously active in different compartments. Plant glycolysis occurs in the cytosol and plastids of green and non-green cells in which the requirements of energy and precursors may be completely different. Because of this, the relevance of plastidial glycolysis could be very different depending on the cell type. In the associated study, we investigated the function of plastidial glycolysis in photosynthetic and heterotrophic cells by specifically driving the expression of plastidial glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in a glyceraldehyde-3-phosphate de…
Phosphoglycerate Kinases Are Co-Regulated to Adjust Metabolism and to Optimize Growth
2017
[EN] In plants, phosphoglycerate kinase (PGK) converts 1,3-bisphosphoglycerate into 3-phosphoglycerate in glycolysis but also participates in the reverse reaction in gluconeogenesis and the Calvin-Benson cycle. In the databases, we found three genes that encode putative PGKs. Arabidopsis (Arabidopsis thaliana) PGK1 was localized exclusively in the chloroplasts of photosynthetic tissues, while PGK2 was expressed in the chloroplast/plastid of photosynthetic and nonphotosynthetic cells. PGK3 was expressed ubiquitously in the cytosol of all studied cell types. Measurements of carbohydrate content and photosynthetic activities in PGK mutants and silenced lines corroborated that PGK1 was the phot…
The Glycerate and Phosphorylated Pathways of Serine Synthesis in Plants : The Branches of Plant Glycolysis Linking Carbon and Nitrogen Metabolism
2018
Serine metabolism in plants has been studied mostly in relation to photorespiration where serine is formed from two molecules of glycine. However, two other pathways of serine formation operate in plants and represent the branches of glycolysis diverging at the level of 3-phosphoglyceric acid. One branch (the glycerate – serine pathway) is initiated in the cytosol and involves glycerate formation from 3-phosphoglycerate, while the other (the phosphorylated serine pathway) operates in plastids and forms phosphohydroxypyruvate as an intermediate. Serine formed in these pathways becomes a precursor of glycine, formate and glycolate accumulating in stress conditions. The pathways can be linked …
Regulation of Nicotiana tabacum osmotic stress-activated protein kinase and its cellular partner GAPDH by nitric oxide in response to salinity
2010
Several studies focusing on elucidating the mechanism of NO (nitric oxide) signalling in plant cells have highlighted that its biological effects are partly mediated by protein kinases. The identity of these kinases and details of how NO modulates their activities, however, remain poorly investigated. In the present study, we have attempted to clarify the mechanisms underlying NO action in the regulation of NtOSAK (Nicotiana tabacum osmotic stress-activated protein kinase), a member of the SNF1 (sucrose non-fermenting 1)-related protein kinase 2 family. We found that in tobacco BY-2 (bright-yellow 2) cells exposed to salt stress, NtOSAK is rapidly activated, partly through a NO-dependent pr…
Arabidopsis plants deficient in plastidial glyceraldehyde-3-phosphate dehydrogenase show alterations in abscisic acid (ABA) signal transduction: inte…
2010
Abscisic acid (ABA) controls plant development and regulates plant responses to environmental stresses. A role for ABA in sugar regulation of plant development has also been well documented although the molecular mechanisms connecting the hormone with sugar signal transduction pathways are not well understood. In this work it is shown that Arabidopsis thaliana mutants deficient in plastidial glycolytic glyceraldehyde-3-phosphate dehydrogenase (gapcp1gapcp2) are ABA insensitive in growth, stomatal closure, and germination assays. The ABA levels of gapcp1gapcp2 were normal, suggesting that the ABA signal transduction pathway is impaired in the mutants. ABA modified gapcp1gapcp2 gene expressio…
Plastidial Glyceraldehyde-3-Phosphate Dehydrogenase Deficiency Leads to Altered Root Development and Affects the Sugar and Amino Acid Balance in Arab…
2009
[EN] Glycolysis is a central metabolic pathway that, in plants, occurs in both the cytosol and the plastids. The glycolytic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate with concomitant reduction of NAD(+) to NADH. Both cytosolic (GAPCs) and plastidial (GAPCps) GAPDH activities have been described. However, the in vivo functions of the plastidial isoforms remain unresolved. In this work, we have identified two Arabidopsis (Arabidopsis thaliana) chloroplast/plastid-localized GAPDH isoforms (GAPCp1 and GAPCp2). gapcp double mutants display a drastic phenotype of arrested root development, dwarfism, and steri…
Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo
2021
Multidrug resistance (MDR) mediated by ATP binding cassette subfamily B member 1 (ABCB1) is significantly hindering effective cancer chemotherapy. However, currently, no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically, mainly due to the inhibitor specificity, toxicity, and drug interactions. Here, we reported that three polyoxypregnanes (POPs) as the most abundant constituents of Marsdenia tenacissima (M. tenacissima) were novel ABCB1-modulatory pro-drugs, which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites. The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells v…