The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Ada Zamir - One of the best experts on this subject based on the ideXlab platform.
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a salt resistant plasma membrane carbonic anhydrase is induced by salt in dunaliella salina
Journal of Biological Chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:Abstract The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at ∼1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was ∼90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
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A Salt-resistant Plasma Membrane Carbonic Anhydrase Is Induced by Salt in Dunaliella salina
The Journal of biological chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at approximately 1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was approximately 90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
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A Salt-Induced 60-Kilodalton Plasma Membrane Protein Plays a Potential Role in the Extreme Halotolerance of the Alga Dunaliella
Plant physiology, 1994Co-Authors: Morly Fisher, Uri Pick, Ada ZamirAbstract:The halotolerant alga Dunaliella salina grows in saline conditions as varied as 0.5 and 5 M NaCl, maintaining throughout this range a low intracellular ion concentration. To discover factors potentially involved in ionic homeostasis, we grew cells in media with different salinities or osmolarities and compared their Protein profiles. The comparisons indicated that the amount of a 60-kD Protein, P60, greatly increased with an increase in salinity and was moderately enhanced when NaCl was substituted with iso-osmotic glycerol. Cells transferred from low to high NaCl or from high glycerol to iso-osmotic NaCl media transiently ceased to grow, and resumption of growth coincided approximately with an increase in P60. The Protein, extracted from a plasma membrane fraction, was purified to homogeneity. Anti-P60 antibodies cross-reacted with a 60-kD Protein in Dunaliella bardawil. Immunoelectron microscopy of D. salina cell sections indicated that P60 was exclusively located in the plasma membrane. Its induction by salt, the correlation between its accumulation and growth resumption in high concentrations of salt, and its plasma membrane localization suggest the possibility that P60 could play a role in ionic homeostasis in conditions of high salinity, although different types of function could also be considered.
Morly Fisher - One of the best experts on this subject based on the ideXlab platform.
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a salt resistant plasma membrane carbonic anhydrase is induced by salt in dunaliella salina
Journal of Biological Chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:Abstract The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at ∼1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was ∼90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
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A Salt-resistant Plasma Membrane Carbonic Anhydrase Is Induced by Salt in Dunaliella salina
The Journal of biological chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at approximately 1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was approximately 90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
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A Salt-Induced 60-Kilodalton Plasma Membrane Protein Plays a Potential Role in the Extreme Halotolerance of the Alga Dunaliella
Plant physiology, 1994Co-Authors: Morly Fisher, Uri Pick, Ada ZamirAbstract:The halotolerant alga Dunaliella salina grows in saline conditions as varied as 0.5 and 5 M NaCl, maintaining throughout this range a low intracellular ion concentration. To discover factors potentially involved in ionic homeostasis, we grew cells in media with different salinities or osmolarities and compared their Protein profiles. The comparisons indicated that the amount of a 60-kD Protein, P60, greatly increased with an increase in salinity and was moderately enhanced when NaCl was substituted with iso-osmotic glycerol. Cells transferred from low to high NaCl or from high glycerol to iso-osmotic NaCl media transiently ceased to grow, and resumption of growth coincided approximately with an increase in P60. The Protein, extracted from a plasma membrane fraction, was purified to homogeneity. Anti-P60 antibodies cross-reacted with a 60-kD Protein in Dunaliella bardawil. Immunoelectron microscopy of D. salina cell sections indicated that P60 was exclusively located in the plasma membrane. Its induction by salt, the correlation between its accumulation and growth resumption in high concentrations of salt, and its plasma membrane localization suggest the possibility that P60 could play a role in ionic homeostasis in conditions of high salinity, although different types of function could also be considered.
William B Pratt - One of the best experts on this subject based on the ideXlab platform.
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Reconstitution of the Steroid Receptor·hsp90 Heterocomplex Assembly System of Rabbit Reticulocyte Lysate
The Journal of biological chemistry, 1996Co-Authors: Kurt D. Dittmar, Kevin A Hutchison, Janet K. Owens-grillo, William B PrattAbstract:Rabbit reticulocyte lysate contains a multiProtein system that assembles steroid receptors into a heterocomplex with hsp90. In the case of the glucocorticoid receptor (GR), the receptor must be bound to hsp90 to bind steroid, and assembly of the GR·hsp90 complex restores the hormone binding domain of the receptor to the steroid binding conformation. Using both direct assay of heterocomplex assembly by Western blotting and indirect assay of assembly by steroid binding, it has previously been determined that the assembly system is both ATP/Mg2+-dependent and K+-dependent and that hsp70 and an acidic 23-kDa Protein (p23) are required to form a functional GR·hsp90 complex. It is also thought that a 60-kDa Protein (P60) may be required for progesterone receptor·hsp90 heterocomplex assembly, but a complete heterocomplex assembly system has never been reconstituted from individual components. In this work, we separate the Proteins of rabbit reticulocyte lysate into three fractions by DEAE chromatography and then reconstitute the GR·hsp90 heterocomplex assembly system in a manner that requires the presence of each fraction. Fraction A contains most of the hsp70 and all of the P60 in lysate, and elimination of P60 by immunoadsorption inactivates this fraction, with bioactivity being restored by the addition of bacterially expressed human P60. The activity of fraction A is replaced by a combination of highly purified rabbit hsp70 and lysate from P60-expressing bacteria. Fraction B contains hsp90, and its activity is replaced by purified rabbit hsp90. Fraction C contains p23, and its activity is replaced in the recombined system by highly purified bacterially expressed human p23. A minimal GR·hsp90 heterocomplex assembly system was reconstituted with purified rabbit hsp70 and hsp90 and bacterially expressed human p23 and P60. This reports the first reconstitution of this apparently ubiquitous Protein folding/heterocomplex assembly system.
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reconstitution of the steroid receptor hsp90 heterocomplex assembly system of rabbit reticulocyte lysate
Journal of Biological Chemistry, 1996Co-Authors: Kurt D. Dittmar, Kevin A Hutchison, Janet K Owensgrillo, William B PrattAbstract:Rabbit reticulocyte lysate contains a multiProtein system that assembles steroid receptors into a heterocomplex with hsp90. In the case of the glucocorticoid receptor (GR), the receptor must be bound to hsp90 to bind steroid, and assembly of the GR·hsp90 complex restores the hormone binding domain of the receptor to the steroid binding conformation. Using both direct assay of heterocomplex assembly by Western blotting and indirect assay of assembly by steroid binding, it has previously been determined that the assembly system is both ATP/Mg2+-dependent and K+-dependent and that hsp70 and an acidic 23-kDa Protein (p23) are required to form a functional GR·hsp90 complex. It is also thought that a 60-kDa Protein (P60) may be required for progesterone receptor·hsp90 heterocomplex assembly, but a complete heterocomplex assembly system has never been reconstituted from individual components. In this work, we separate the Proteins of rabbit reticulocyte lysate into three fractions by DEAE chromatography and then reconstitute the GR·hsp90 heterocomplex assembly system in a manner that requires the presence of each fraction. Fraction A contains most of the hsp70 and all of the P60 in lysate, and elimination of P60 by immunoadsorption inactivates this fraction, with bioactivity being restored by the addition of bacterially expressed human P60. The activity of fraction A is replaced by a combination of highly purified rabbit hsp70 and lysate from P60-expressing bacteria. Fraction B contains hsp90, and its activity is replaced by purified rabbit hsp90. Fraction C contains p23, and its activity is replaced in the recombined system by highly purified bacterially expressed human p23. A minimal GR·hsp90 heterocomplex assembly system was reconstituted with purified rabbit hsp70 and hsp90 and bacterially expressed human p23 and P60. This reports the first reconstitution of this apparently ubiquitous Protein folding/heterocomplex assembly system.
Uri Pick - One of the best experts on this subject based on the ideXlab platform.
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a salt resistant plasma membrane carbonic anhydrase is induced by salt in dunaliella salina
Journal of Biological Chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:Abstract The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at ∼1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was ∼90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
-
A Salt-resistant Plasma Membrane Carbonic Anhydrase Is Induced by Salt in Dunaliella salina
The Journal of biological chemistry, 1996Co-Authors: Morly Fisher, Irena Gokhman, Uri Pick, Ada ZamirAbstract:The mechanisms allowing proliferation of the unicellular green alga Dunaliella salina in up to saturating NaCl concentrations are only partially understood at present. Previously, the level of a plasma membrane Mr 60,000 Protein, P60, was found to increase with rising external salinities. Based on cDNA cloning and enzymatic assays, it is now shown that P60 is an internally duplicated carbonic anhydrase, with each repeat homologous to animal and Chlamydomonas reinhardtii carbonic anhydrases, but exceptional in the excess of acidic over basic residues. Increasing salinities, alkaline shift, or removal of bicarbonate induced in D. salina parallel increases in the levels of P60, its mRNA, and external carbonic anhydrase activity. Moreover, purified P60 exhibited carbonic anhydrase activity comparable to other carbonic anhydrases. A P60-enriched soluble preparation showed maximal carbonic anhydrase activity at approximately 1.0 M NaCl and retained considerable activity at higher salt concentrations. In contrast, a similar preparation from C. reinhardtii was approximately 90% inhibited in 0.6 M NaCl. These results identified P60 as a structurally novel carbonic anhydrase transcriptionally regulated by CO2 availability and exhibiting halophilic-like characteristics. This enzyme is potentially suited to optimize CO2 uptake by cells growing in hypersaline media.
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A Salt-Induced 60-Kilodalton Plasma Membrane Protein Plays a Potential Role in the Extreme Halotolerance of the Alga Dunaliella
Plant physiology, 1994Co-Authors: Morly Fisher, Uri Pick, Ada ZamirAbstract:The halotolerant alga Dunaliella salina grows in saline conditions as varied as 0.5 and 5 M NaCl, maintaining throughout this range a low intracellular ion concentration. To discover factors potentially involved in ionic homeostasis, we grew cells in media with different salinities or osmolarities and compared their Protein profiles. The comparisons indicated that the amount of a 60-kD Protein, P60, greatly increased with an increase in salinity and was moderately enhanced when NaCl was substituted with iso-osmotic glycerol. Cells transferred from low to high NaCl or from high glycerol to iso-osmotic NaCl media transiently ceased to grow, and resumption of growth coincided approximately with an increase in P60. The Protein, extracted from a plasma membrane fraction, was purified to homogeneity. Anti-P60 antibodies cross-reacted with a 60-kD Protein in Dunaliella bardawil. Immunoelectron microscopy of D. salina cell sections indicated that P60 was exclusively located in the plasma membrane. Its induction by salt, the correlation between its accumulation and growth resumption in high concentrations of salt, and its plasma membrane localization suggest the possibility that P60 could play a role in ionic homeostasis in conditions of high salinity, although different types of function could also be considered.
Kurt D. Dittmar - One of the best experts on this subject based on the ideXlab platform.
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Reconstitution of the Steroid Receptor·hsp90 Heterocomplex Assembly System of Rabbit Reticulocyte Lysate
The Journal of biological chemistry, 1996Co-Authors: Kurt D. Dittmar, Kevin A Hutchison, Janet K. Owens-grillo, William B PrattAbstract:Rabbit reticulocyte lysate contains a multiProtein system that assembles steroid receptors into a heterocomplex with hsp90. In the case of the glucocorticoid receptor (GR), the receptor must be bound to hsp90 to bind steroid, and assembly of the GR·hsp90 complex restores the hormone binding domain of the receptor to the steroid binding conformation. Using both direct assay of heterocomplex assembly by Western blotting and indirect assay of assembly by steroid binding, it has previously been determined that the assembly system is both ATP/Mg2+-dependent and K+-dependent and that hsp70 and an acidic 23-kDa Protein (p23) are required to form a functional GR·hsp90 complex. It is also thought that a 60-kDa Protein (P60) may be required for progesterone receptor·hsp90 heterocomplex assembly, but a complete heterocomplex assembly system has never been reconstituted from individual components. In this work, we separate the Proteins of rabbit reticulocyte lysate into three fractions by DEAE chromatography and then reconstitute the GR·hsp90 heterocomplex assembly system in a manner that requires the presence of each fraction. Fraction A contains most of the hsp70 and all of the P60 in lysate, and elimination of P60 by immunoadsorption inactivates this fraction, with bioactivity being restored by the addition of bacterially expressed human P60. The activity of fraction A is replaced by a combination of highly purified rabbit hsp70 and lysate from P60-expressing bacteria. Fraction B contains hsp90, and its activity is replaced by purified rabbit hsp90. Fraction C contains p23, and its activity is replaced in the recombined system by highly purified bacterially expressed human p23. A minimal GR·hsp90 heterocomplex assembly system was reconstituted with purified rabbit hsp70 and hsp90 and bacterially expressed human p23 and P60. This reports the first reconstitution of this apparently ubiquitous Protein folding/heterocomplex assembly system.
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reconstitution of the steroid receptor hsp90 heterocomplex assembly system of rabbit reticulocyte lysate
Journal of Biological Chemistry, 1996Co-Authors: Kurt D. Dittmar, Kevin A Hutchison, Janet K Owensgrillo, William B PrattAbstract:Rabbit reticulocyte lysate contains a multiProtein system that assembles steroid receptors into a heterocomplex with hsp90. In the case of the glucocorticoid receptor (GR), the receptor must be bound to hsp90 to bind steroid, and assembly of the GR·hsp90 complex restores the hormone binding domain of the receptor to the steroid binding conformation. Using both direct assay of heterocomplex assembly by Western blotting and indirect assay of assembly by steroid binding, it has previously been determined that the assembly system is both ATP/Mg2+-dependent and K+-dependent and that hsp70 and an acidic 23-kDa Protein (p23) are required to form a functional GR·hsp90 complex. It is also thought that a 60-kDa Protein (P60) may be required for progesterone receptor·hsp90 heterocomplex assembly, but a complete heterocomplex assembly system has never been reconstituted from individual components. In this work, we separate the Proteins of rabbit reticulocyte lysate into three fractions by DEAE chromatography and then reconstitute the GR·hsp90 heterocomplex assembly system in a manner that requires the presence of each fraction. Fraction A contains most of the hsp70 and all of the P60 in lysate, and elimination of P60 by immunoadsorption inactivates this fraction, with bioactivity being restored by the addition of bacterially expressed human P60. The activity of fraction A is replaced by a combination of highly purified rabbit hsp70 and lysate from P60-expressing bacteria. Fraction B contains hsp90, and its activity is replaced by purified rabbit hsp90. Fraction C contains p23, and its activity is replaced in the recombined system by highly purified bacterially expressed human p23. A minimal GR·hsp90 heterocomplex assembly system was reconstituted with purified rabbit hsp70 and hsp90 and bacterially expressed human p23 and P60. This reports the first reconstitution of this apparently ubiquitous Protein folding/heterocomplex assembly system.
