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Xue-chen Wang - One of the best experts on this subject based on the ideXlab platform.
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glucose inhibits the expression of Triose phosphate phosphate translocator gene in wheat via hexokinase dependent mechanism
The International Journal of Biochemistry & Cell Biology, 2006Co-Authors: Jin-yue Sun, Ye-miao Chen, Qing-mei Wang, Jia Chen, Xue-chen WangAbstract:Although Triose phosphate/phosphate translocator is known to play an important role in regulating the distribution of assimilates in wheat chloroplasts, the mechanism of Triose phosphate/phosphate translocator gene control has not yet been clearly elucidated. We first showed that glucose inhibited the expression of Triose phosphate/phosphate translocator gene in wheat by reverse transcription-polymerase chain reaction and Western blotting. The Triose phosphate/phosphate translocator expression was seriously impaired by 5 mmol/L glucose, and it responded slowly, more than 48 h, to level as low as 1 mmol/L glucose. Both glucose and 2-deoxyglucose inhibited the expression of Triose phosphate/phosphate translocator gene, but 2-deoxyglucose-6-P, product of phosphorylated 2-deoxyglucose, cannot be further metabolized, therefore the further metabolism of phosphorylated glucose by hexokinase is not a prerequisite for triggering glucose-regulated expression of Triose phosphate/phosphate translocator gene. Glucose had little inhibitory effect on the expression of Triose phosphate/phosphate translocator gene when hexokinase activity was reduced or eliminated by transforming wheat protoplasts with a hexokinase antisense construct or treating protoplasts with glucosamine, an inhibitor of hexokinase. Therefore, it appears essential for hexokinase to retain phosphorylation activity for glucose to regulate the expression of Triose phosphate/phosphate translocator gene. The treatment of protoplasts with glucose-6-phosphate resulting in no inhibition of Triose phosphate/phosphate translocator expression demonstrated that phosphorylation via hexokinase is necessary for glucose inhibiting Triose phosphate/phosphate translocator expression. All the data suggest that Triose phosphate/phosphate translocator is regulated by glucose via a hexokinase-dependent pathway.
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Glucose inhibits the expression of Triose phosphate/phosphate translocator gene in wheat via hexokinase-dependent mechanism.
The international journal of biochemistry & cell biology, 2005Co-Authors: Jin-yue Sun, Ye-miao Chen, Qing-mei Wang, Jia Chen, Xue-chen WangAbstract:Although Triose phosphate/phosphate translocator is known to play an important role in regulating the distribution of assimilates in wheat chloroplasts, the mechanism of Triose phosphate/phosphate translocator gene control has not yet been clearly elucidated. We first showed that glucose inhibited the expression of Triose phosphate/phosphate translocator gene in wheat by reverse transcription-polymerase chain reaction and Western blotting. The Triose phosphate/phosphate translocator expression was seriously impaired by 5 mmol/L glucose, and it responded slowly, more than 48 h, to level as low as 1 mmol/L glucose. Both glucose and 2-deoxyglucose inhibited the expression of Triose phosphate/phosphate translocator gene, but 2-deoxyglucose-6-P, product of phosphorylated 2-deoxyglucose, cannot be further metabolized, therefore the further metabolism of phosphorylated glucose by hexokinase is not a prerequisite for triggering glucose-regulated expression of Triose phosphate/phosphate translocator gene. Glucose had little inhibitory effect on the expression of Triose phosphate/phosphate translocator gene when hexokinase activity was reduced or eliminated by transforming wheat protoplasts with a hexokinase antisense construct or treating protoplasts with glucosamine, an inhibitor of hexokinase. Therefore, it appears essential for hexokinase to retain phosphorylation activity for glucose to regulate the expression of Triose phosphate/phosphate translocator gene. The treatment of protoplasts with glucose-6-phosphate resulting in no inhibition of Triose phosphate/phosphate translocator expression demonstrated that phosphorylation via hexokinase is necessary for glucose inhibiting Triose phosphate/phosphate translocator expression. All the data suggest that Triose phosphate/phosphate translocator is regulated by glucose via a hexokinase-dependent pathway.
Jin-yue Sun - One of the best experts on this subject based on the ideXlab platform.
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glucose inhibits the expression of Triose phosphate phosphate translocator gene in wheat via hexokinase dependent mechanism
The International Journal of Biochemistry & Cell Biology, 2006Co-Authors: Jin-yue Sun, Ye-miao Chen, Qing-mei Wang, Jia Chen, Xue-chen WangAbstract:Although Triose phosphate/phosphate translocator is known to play an important role in regulating the distribution of assimilates in wheat chloroplasts, the mechanism of Triose phosphate/phosphate translocator gene control has not yet been clearly elucidated. We first showed that glucose inhibited the expression of Triose phosphate/phosphate translocator gene in wheat by reverse transcription-polymerase chain reaction and Western blotting. The Triose phosphate/phosphate translocator expression was seriously impaired by 5 mmol/L glucose, and it responded slowly, more than 48 h, to level as low as 1 mmol/L glucose. Both glucose and 2-deoxyglucose inhibited the expression of Triose phosphate/phosphate translocator gene, but 2-deoxyglucose-6-P, product of phosphorylated 2-deoxyglucose, cannot be further metabolized, therefore the further metabolism of phosphorylated glucose by hexokinase is not a prerequisite for triggering glucose-regulated expression of Triose phosphate/phosphate translocator gene. Glucose had little inhibitory effect on the expression of Triose phosphate/phosphate translocator gene when hexokinase activity was reduced or eliminated by transforming wheat protoplasts with a hexokinase antisense construct or treating protoplasts with glucosamine, an inhibitor of hexokinase. Therefore, it appears essential for hexokinase to retain phosphorylation activity for glucose to regulate the expression of Triose phosphate/phosphate translocator gene. The treatment of protoplasts with glucose-6-phosphate resulting in no inhibition of Triose phosphate/phosphate translocator expression demonstrated that phosphorylation via hexokinase is necessary for glucose inhibiting Triose phosphate/phosphate translocator expression. All the data suggest that Triose phosphate/phosphate translocator is regulated by glucose via a hexokinase-dependent pathway.
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Glucose inhibits the expression of Triose phosphate/phosphate translocator gene in wheat via hexokinase-dependent mechanism.
The international journal of biochemistry & cell biology, 2005Co-Authors: Jin-yue Sun, Ye-miao Chen, Qing-mei Wang, Jia Chen, Xue-chen WangAbstract:Although Triose phosphate/phosphate translocator is known to play an important role in regulating the distribution of assimilates in wheat chloroplasts, the mechanism of Triose phosphate/phosphate translocator gene control has not yet been clearly elucidated. We first showed that glucose inhibited the expression of Triose phosphate/phosphate translocator gene in wheat by reverse transcription-polymerase chain reaction and Western blotting. The Triose phosphate/phosphate translocator expression was seriously impaired by 5 mmol/L glucose, and it responded slowly, more than 48 h, to level as low as 1 mmol/L glucose. Both glucose and 2-deoxyglucose inhibited the expression of Triose phosphate/phosphate translocator gene, but 2-deoxyglucose-6-P, product of phosphorylated 2-deoxyglucose, cannot be further metabolized, therefore the further metabolism of phosphorylated glucose by hexokinase is not a prerequisite for triggering glucose-regulated expression of Triose phosphate/phosphate translocator gene. Glucose had little inhibitory effect on the expression of Triose phosphate/phosphate translocator gene when hexokinase activity was reduced or eliminated by transforming wheat protoplasts with a hexokinase antisense construct or treating protoplasts with glucosamine, an inhibitor of hexokinase. Therefore, it appears essential for hexokinase to retain phosphorylation activity for glucose to regulate the expression of Triose phosphate/phosphate translocator gene. The treatment of protoplasts with glucose-6-phosphate resulting in no inhibition of Triose phosphate/phosphate translocator expression demonstrated that phosphorylation via hexokinase is necessary for glucose inhibiting Triose phosphate/phosphate translocator expression. All the data suggest that Triose phosphate/phosphate translocator is regulated by glucose via a hexokinase-dependent pathway.
Andrew A. Carol - One of the best experts on this subject based on the ideXlab platform.
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Enzyme co-localization in pea leaf chloroplasts: glyceraldehyde-3-P dehydrogenase, Triose-P isomerase, aldolase and sedoheptulose bisphosphatase
Photosynthesis Research, 2005Co-Authors: Louise E. Anderson, Nandita Gatla, Andrew A. CarolAbstract:Nearest neighbor analysis of immunocytolocalization experiments indicates that the enzymes glyceraldehyde-3-P dehydrogenase, Triose-P isomerase and aldolase are located close to one another in the pea leaf chloroplast stroma, and that aldolase is located close to sedoheptulose bisphosphatase. Direct transfer of the Triose phosphates between glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, and from glyceraldehyde-3-P dehydrogenase and Triose-P isomerase to aldolase, is then a possibility, as is direct transfer of sedoheptulose bisphosphate from aldolase to sedoheptulose bisphosphatase. Spatial organization of these enzymes may be important for efficient CO_2 fixation in photosynthetic organisms. In contrast, there is no indication that fructose bisphosphatase is co-localized with aldolase, and direct transfer of fructose bisphosphate from aldolase to fructose bisphosphatase seems unlikely.
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Enzyme co-localization in the pea leaf cytosol: 3-P-glycerate kinase, glyceraldehyde-3-P dehydrogenase, Triose-P isomerase and aldolase
Plant Science, 2005Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Abstract Nearest neighbor analysis of immunocytolocalization experiments indicates that the Embden–Meyerhof pathway enzymes aldolase, Triose-P isomerase, glyceraldehyde-3-P dehydrogenase and P-glycerate kinase are located close to one another in the pea leaf cytosol. Direct transfer of the Triose phosphates between aldolase, glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, direct transfer of glyceraldehyde-3-P between glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, and direct transfer of 1,3-P2-glycerate between glyceraldehyde-3-P dehydrogenase and P-glycerate kinase is then a possibility in the plant cytosol. In contrast, there is no indication that fructose bisphosphatase is co-localized with aldolase, and it unlikely that fructose bisphosphate is channeled from aldolase to fructose bisphosphatase in this system.
Ulf-ingo Flügge - One of the best experts on this subject based on the ideXlab platform.
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expression of the functional mature chloroplast Triose phosphate translocator in yeast internal membranes and purification of the histidine tagged protein by a single metal affinity chromatography step
Proceedings of the National Academy of Sciences of the United States of America, 1993Co-Authors: Brigitte Loddenkotter, Karsten Fischer, Birgit Kammerer, Ulf-ingo FlüggeAbstract:Abstract The mature part of the chloroplast Triose phosphate-phosphate translocator was cloned into the yeast expression vector pEVP11. This construct was used to transform cells from both Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. The chloroplast translocator protein was functionally expressed in the transformed yeast cells and represented about 1-2% of the Sch. pombe cell membrane protein. It was localized to mitochondrial membranes and/or membranes of the rough endoplasmic reticulum. In order to purify the recombinant translocator protein, a sequence encoding a C-terminal tag of six histidine residues was introduced into the corresponding cDNA. The expressed histidine-tagged translocator protein was purified from the transformed yeast cells under nondenaturing conditions to apparent homogeneity by a single-step affinity chromatography using a Ni2+. nitrilotriacetic acid resin. Both the expressed Triose phosphate translocator and the recombinant histidine-tagged protein possess substrate specificities identical to those of the authentic chloroplast protein, providing definitive evidence for its identity as the Triose phosphate translocator and further disproving its assignment as the receptor for chloroplast protein import. The yeast expression system in combination with the Ni2+. nitrilotriacetic acid chromatography thus provides a valuable tool for the production of purified membrane proteins in a functional state.
Louise E. Anderson - One of the best experts on this subject based on the ideXlab platform.
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Enzyme co-localization in pea leaf chloroplasts: glyceraldehyde-3-P dehydrogenase, Triose-P isomerase, aldolase and sedoheptulose bisphosphatase
Photosynthesis Research, 2005Co-Authors: Louise E. Anderson, Nandita Gatla, Andrew A. CarolAbstract:Nearest neighbor analysis of immunocytolocalization experiments indicates that the enzymes glyceraldehyde-3-P dehydrogenase, Triose-P isomerase and aldolase are located close to one another in the pea leaf chloroplast stroma, and that aldolase is located close to sedoheptulose bisphosphatase. Direct transfer of the Triose phosphates between glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, and from glyceraldehyde-3-P dehydrogenase and Triose-P isomerase to aldolase, is then a possibility, as is direct transfer of sedoheptulose bisphosphate from aldolase to sedoheptulose bisphosphatase. Spatial organization of these enzymes may be important for efficient CO_2 fixation in photosynthetic organisms. In contrast, there is no indication that fructose bisphosphatase is co-localized with aldolase, and direct transfer of fructose bisphosphate from aldolase to fructose bisphosphatase seems unlikely.
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Enzyme co-localization in the pea leaf cytosol: 3-P-glycerate kinase, glyceraldehyde-3-P dehydrogenase, Triose-P isomerase and aldolase
Plant Science, 2005Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Abstract Nearest neighbor analysis of immunocytolocalization experiments indicates that the Embden–Meyerhof pathway enzymes aldolase, Triose-P isomerase, glyceraldehyde-3-P dehydrogenase and P-glycerate kinase are located close to one another in the pea leaf cytosol. Direct transfer of the Triose phosphates between aldolase, glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, direct transfer of glyceraldehyde-3-P between glyceraldehyde-3-P dehydrogenase and Triose-P isomerase, and direct transfer of 1,3-P2-glycerate between glyceraldehyde-3-P dehydrogenase and P-glycerate kinase is then a possibility in the plant cytosol. In contrast, there is no indication that fructose bisphosphatase is co-localized with aldolase, and it unlikely that fructose bisphosphate is channeled from aldolase to fructose bisphosphatase in this system.
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Enzyme-enzyme interaction in the chloroplast: Glyceraldehyde-3-phosphate dehydrogenase, Triose phosphate isomerase and aldolase
Planta, 1995Co-Authors: Louise E. Anderson, Ilana M. Goldhaber-gordon, Xiao-yi Tang, Minghui Xiang, Namita PrakashAbstract:Apparent physical interaction between pea chloroplast (Pisum sativum L.) glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13) and aldolase (EC 4.1.2.13) is seen in phase-partitioning, fluorescent-anisotropy and isoelectric-focusing experiments. Similarly, results obtained in phase-partitioning and isoelectric-focusing experiments indicate physical interaction between aldolase and Triose-phosphate isomerase (EC 5.3.1.1). Kinetic experiments suggest that both aldolase-bound glyceraldehyde-3-phosphate and Triose-phosphate isomerase bound glyceraldehyde-3-phosphate can act as substrate for glyceraldehyde-3-phosphate dehydrogenase. These results are consistent with the notion that there is interaction between these three enzymes both during photosynthetic CO2 fixation and during glycolysis in the chloroplast.