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Tsukaho Hattori - One of the best experts on this subject based on the ideXlab platform.
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α tubulin is rapidly phosphorylated in response to Hyperosmotic Stress in rice and arabidopsis
Plant and Cell Physiology, 2013Co-Authors: Yuhko Kobayashi, Tomomi Hara, Takahiro Hamada, Takashi Hashimoto, Shin Takeda, Tsukaho HattoriAbstract:By using high-resolution two-dimensional PAGE followed by phosphoprotein-specific staining and peptide mass fingerprint analysis along with other assays, we found that α-tubulin is phosphorylated in response to Hyperosmotic Stress in rice and Arabidopsis. The onset of the phosphorylation response was as early as 2 min after Hyperosmotic Stress treatment, and a major proportion of α-tubulin was phosphorylated after 60 min in root tissues. However, the phosphorylated form of α-tubulin was readily dephosphorylated upon Stress removal. The phosphorylation site was identified as Thr-349 by comprehensive mutagenesis of Ser/Thr residues in a rice α-tubulin isoform followed by evaluation in cultured cell protoplasts. This residue is located at the surface for the interaction with β-tubulin in polymerized α-β tubulin dimers and has been proposed to be directly involved in this interaction. Thus, α-tubulin phosphorylation was considered to occur on free tubulin dimers in response to Hyperosmotic Stress. The incorporation of GFP-α-tubulin into cortical microtubules was completely inhibited in transgenic Arabidopsis when Thr-349 was substituted with Glu or Asp. Using transgenic Arabidopsis plants expressing GFP-α-tubulin, we found that Hyperosmotic Stress causes extensive cortical microtubule depolymerization. Microtubule destabilizing treatments such as propyzamide or oryzalin and temperature Stresses resulted in α-tubulin phosphorylation, whereas Hyperosmotic Stress-induced α-tubulin phosphorylation was partially inhibited by taxol, which stabilizes microtubules. These results and the three-dimensional location of the phosphorylation site suggested that microtubules are depolymerized in response to Hyperosmotic Stress via α-tubulin phosphorylation. Together, the present study reveals a novel mechanism that globally regulates the microtubule polymerization.
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differential activation of the rice sucrose nonfermenting1 related protein kinase2 family by Hyperosmotic Stress and abscisic acid
The Plant Cell, 2004Co-Authors: Yuhko Kobayashi, Shuhei Yamamoto, Hideyuki Minami, Yasuaki Kagaya, Tsukaho HattoriAbstract:To date, a large number of sequences of protein kinases that belong to the sucrose nonfermenting1-related protein kinase2 (SnRK2) family are found in databases. However, only limited numbers of the family members have been characterized and implicated in abscisic acid (ABA) and Hyperosmotic Stress signaling. We identified 10 SnRK2 protein kinases encoded by the rice (Oryza sativa) genome. Each of the 10 members was expressed in cultured cell protoplasts, and its regulation was analyzed. Here, we demonstrate that all family members are activated by Hyperosmotic Stress and that three of them are also activated by ABA. Surprisingly, there were no members that were activated only by ABA. The activation was found to be regulated via phosphorylation. In addition to the functional distinction with respect to ABA regulation, dependence of activation on the Hyperosmotic strength was different among the members. We show that the relatively diverged C-terminal domain is mainly responsible for this functional distinction, although the kinase domain also contributes to these differences. The results indicated that the SnRK2 protein kinase family has evolved specifically for Hyperosmotic Stress signaling and that individual members have acquired distinct regulatory properties, including ABA responsiveness by modifying the C-terminal domain.
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Differential Activation of the Rice Sucrose Nonfermenting1–Related Protein Kinase2 Family by Hyperosmotic Stress and Abscisic Acid
The Plant Cell, 2004Co-Authors: Yuhko Kobayashi, Shuhei Yamamoto, Hideyuki Minami, Yasuaki Kagaya, Tsukaho HattoriAbstract:To date, a large number of sequences of protein kinases that belong to the sucrose nonfermenting1-related protein kinase2 (SnRK2) family are found in databases. However, only limited numbers of the family members have been characterized and implicated in abscisic acid (ABA) and Hyperosmotic Stress signaling. We identified 10 SnRK2 protein kinases encoded by the rice (Oryza sativa) genome. Each of the 10 members was expressed in cultured cell protoplasts, and its regulation was analyzed. Here, we demonstrate that all family members are activated by Hyperosmotic Stress and that three of them are also activated by ABA. Surprisingly, there were no members that were activated only by ABA. The activation was found to be regulated via phosphorylation. In addition to the functional distinction with respect to ABA regulation, dependence of activation on the Hyperosmotic strength was different among the members. We show that the relatively diverged C-terminal domain is mainly responsible for this functional distinction, although the kinase domain also contributes to these differences. The results indicated that the SnRK2 protein kinase family has evolved specifically for Hyperosmotic Stress signaling and that individual members have acquired distinct regulatory properties, including ABA responsiveness by modifying the C-terminal domain.
Yuhko Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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α tubulin is rapidly phosphorylated in response to Hyperosmotic Stress in rice and arabidopsis
Plant and Cell Physiology, 2013Co-Authors: Yuhko Kobayashi, Tomomi Hara, Takahiro Hamada, Takashi Hashimoto, Shin Takeda, Tsukaho HattoriAbstract:By using high-resolution two-dimensional PAGE followed by phosphoprotein-specific staining and peptide mass fingerprint analysis along with other assays, we found that α-tubulin is phosphorylated in response to Hyperosmotic Stress in rice and Arabidopsis. The onset of the phosphorylation response was as early as 2 min after Hyperosmotic Stress treatment, and a major proportion of α-tubulin was phosphorylated after 60 min in root tissues. However, the phosphorylated form of α-tubulin was readily dephosphorylated upon Stress removal. The phosphorylation site was identified as Thr-349 by comprehensive mutagenesis of Ser/Thr residues in a rice α-tubulin isoform followed by evaluation in cultured cell protoplasts. This residue is located at the surface for the interaction with β-tubulin in polymerized α-β tubulin dimers and has been proposed to be directly involved in this interaction. Thus, α-tubulin phosphorylation was considered to occur on free tubulin dimers in response to Hyperosmotic Stress. The incorporation of GFP-α-tubulin into cortical microtubules was completely inhibited in transgenic Arabidopsis when Thr-349 was substituted with Glu or Asp. Using transgenic Arabidopsis plants expressing GFP-α-tubulin, we found that Hyperosmotic Stress causes extensive cortical microtubule depolymerization. Microtubule destabilizing treatments such as propyzamide or oryzalin and temperature Stresses resulted in α-tubulin phosphorylation, whereas Hyperosmotic Stress-induced α-tubulin phosphorylation was partially inhibited by taxol, which stabilizes microtubules. These results and the three-dimensional location of the phosphorylation site suggested that microtubules are depolymerized in response to Hyperosmotic Stress via α-tubulin phosphorylation. Together, the present study reveals a novel mechanism that globally regulates the microtubule polymerization.
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differential activation of the rice sucrose nonfermenting1 related protein kinase2 family by Hyperosmotic Stress and abscisic acid
The Plant Cell, 2004Co-Authors: Yuhko Kobayashi, Shuhei Yamamoto, Hideyuki Minami, Yasuaki Kagaya, Tsukaho HattoriAbstract:To date, a large number of sequences of protein kinases that belong to the sucrose nonfermenting1-related protein kinase2 (SnRK2) family are found in databases. However, only limited numbers of the family members have been characterized and implicated in abscisic acid (ABA) and Hyperosmotic Stress signaling. We identified 10 SnRK2 protein kinases encoded by the rice (Oryza sativa) genome. Each of the 10 members was expressed in cultured cell protoplasts, and its regulation was analyzed. Here, we demonstrate that all family members are activated by Hyperosmotic Stress and that three of them are also activated by ABA. Surprisingly, there were no members that were activated only by ABA. The activation was found to be regulated via phosphorylation. In addition to the functional distinction with respect to ABA regulation, dependence of activation on the Hyperosmotic strength was different among the members. We show that the relatively diverged C-terminal domain is mainly responsible for this functional distinction, although the kinase domain also contributes to these differences. The results indicated that the SnRK2 protein kinase family has evolved specifically for Hyperosmotic Stress signaling and that individual members have acquired distinct regulatory properties, including ABA responsiveness by modifying the C-terminal domain.
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Differential Activation of the Rice Sucrose Nonfermenting1–Related Protein Kinase2 Family by Hyperosmotic Stress and Abscisic Acid
The Plant Cell, 2004Co-Authors: Yuhko Kobayashi, Shuhei Yamamoto, Hideyuki Minami, Yasuaki Kagaya, Tsukaho HattoriAbstract:To date, a large number of sequences of protein kinases that belong to the sucrose nonfermenting1-related protein kinase2 (SnRK2) family are found in databases. However, only limited numbers of the family members have been characterized and implicated in abscisic acid (ABA) and Hyperosmotic Stress signaling. We identified 10 SnRK2 protein kinases encoded by the rice (Oryza sativa) genome. Each of the 10 members was expressed in cultured cell protoplasts, and its regulation was analyzed. Here, we demonstrate that all family members are activated by Hyperosmotic Stress and that three of them are also activated by ABA. Surprisingly, there were no members that were activated only by ABA. The activation was found to be regulated via phosphorylation. In addition to the functional distinction with respect to ABA regulation, dependence of activation on the Hyperosmotic strength was different among the members. We show that the relatively diverged C-terminal domain is mainly responsible for this functional distinction, although the kinase domain also contributes to these differences. The results indicated that the SnRK2 protein kinase family has evolved specifically for Hyperosmotic Stress signaling and that individual members have acquired distinct regulatory properties, including ABA responsiveness by modifying the C-terminal domain.
Norio Murata - One of the best experts on this subject based on the ideXlab platform.
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salt Stress and Hyperosmotic Stress regulate the expression of different sets of genes in synechocystis sp pcc 6803
Biochemical and Biophysical Research Communications, 2002Co-Authors: Yu Kanesaki, Iwane Suzuki, Suleyman I Allakhverdiev, Koji Mikami, Norio MurataAbstract:Acclimation of microorganisms to environmental Stress is closely related to the expression of various genes. We report here that salt Stress and Hyperosmotic Stress have different effects on the cytoplasmic volume and gene expression in Synechocystis sp. PCC 6803. DNA microarray analysis indicated that salt Stress strongly induced the genes for some ribosomal proteins. Hyperosmotic Stress strongly induced the genes for 3-ketoacyl-acyl carrier protein reductase and rare lipoprotein A. Genes whose expression was induced both by salt Stress and by Hyperosmotic Stress included those for heat-shock proteins and the enzymes for the synthesis of glucosylglycerol. We also found that each kind of Stress induced a number of genes for proteins of unknown function. Our findings suggest that Synechocystis recognizes salt Stress and Hyperosmotic Stress as different stimuli, although mechanisms common to the responses to each form of Stress might also contribute to gene expression.
Luo Lu - One of the best experts on this subject based on the ideXlab platform.
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Hyperosmotic Stress induced corneal epithelial cell death through activation of polo like kinase 3 and c jun
Investigative Ophthalmology & Visual Science, 2011Co-Authors: Ling Wang, Luo LuAbstract:The corneal epithelial layer in the front of the eye forms the first line of defense to protect the structures behind the cornea from the insults and injuries of environmental hazards, including Hyperosmotic Stress.1 Changes in extracellular osmotic pressure are often found in some pathologic conditions, such as diabetes mellitus, uremia, dehydration after exercise, heat shock, fatal burns, and inflammation sites in various tissues, including the cornea.2–5 In the cornea, Hyperosmotic Stress from environmental and pathologic conditions strikes the epithelial cells and alters the fluid balance, resulting in cell shrinkage, which may contribute to delayed wound healing and dry eye diseases.6 Hyperosmotic Stress extracts water from the cell, inducing cell shrinkage. To restore the volume, cells undergo a process of regulated volume increase within several minutes by the uptake of inorganic ions and water.7–9 Cell shrinkage and increased ionic strength alternate cell architecture compartments, denature proteins, and disturb cell function.10–12 It has been shown that persistent Hyperosmotic Stress can induce DNA damage, cell cycle arrest, and apoptosis.11,13 Hyperosmotic Stress induces a series of changes in intracellular kinase cascades that include the activation of JNK, p38, and other signaling pathways to activate the important AP-1 (activating protein-1) transcription factor complex.12,14–16 AP-1 acts as a central switch, in addition to the NF-κB and NFAT5 pathway, which has been known as a primary pathway in response to osmotic Stress, to convert extracellular signals into genetic responses by regulating Stress-related gene expression to determine cell proliferation, differentiation, and apoptosis.17,18 One of the important Hyperosmotic Stress-activated transcription factors is c-Jun, which participates in the formation of AP-1 dimers with a group of the other transcription factors, such as members of the Jun, Fos, and ATF families.19,20 In response to Stress stimulation, c-Jun is activated mainly through the JNK signaling pathway in various cell types, including corneal epithelial cells. In addition, activation of the JNK signaling pathway by Stress stimulation results in increased cell mobility and apoptosis.21–24 In addition, Hyperosmotic Stress can induce the production of certain corneal epithelial proteins, resulting in decreased cell viability through JNK MAPK-mediated pathways.25 In our previous studies, we found that c-Jun can also be activated by UV irradiation and hypoxia/reoxygenation Stress through activation of the Polo-like kinase 3 (Plk3) signaling pathway in corneal epithelial cells.26,27 In mammalian cells, Plk3 belongs to a family consisting of four members (Plk1, Plk2, Plk3, Plk4) that share highly conserved homologies to Drosophila Polo kinase.28–31 All Plk family members contain a kinase domain (KD) at the N terminus that phosphorylates downstream proteins at serine/threonine residues and a Polo-box domain (PBD) at the C terminus that binds to interactive motifs in the target proteins. As a multifunctional protein, Plk3 is involved in regulating a variety of molecular and intracellular events, including DNA damage response, cell cycle control, and apoptosis.32,33 Plk3 undergoes substantial changes in its kinase activity and subcellular distribution after cell cycle progression. Plk3 is rapidly activated on Stress stimulation by ionizing radiation, reactive oxygen species, methylmethane sulfonate, UV irradiation, and hypoxia.26,27,34 In addition, hypoxic Stress-induced delay of corneal epithelial wound healing is significantly improved in Plk3-deficient mice, indicating that Plk3 plays an important role in the wound healing process.26 However, it is still unclear in Hyperosmotic Stress-stimulated cells whether Plk3 is activated and how active Plk3 phosphorylates c-Jun to regulate cell function. In the present study, we report that Plk3 is involved in Hyperosmotic Stress-induced cell death through the phosphorylation of c-Jun protein to activate c-Jun in corneal epithelial cells. Our results reveal that Plk3 plays an important role in the signaling cascades to transmit extracellular Hyperosmotic Stress signals to the regulation of c-Jun in the AP-1 transcription complex in addition to the known JNK signaling pathway, which has been recognized to connect Hyperosmotic Stress stimulation to cell fate.
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Hyperosmotic Stress induced atf 2 activation through polo like kinase 3 in human corneal epithelial cells
Journal of Biological Chemistry, 2011Co-Authors: Ling Wang, Reid Payton, Luo LuAbstract:Elevated extracellular solute concentration (Hyperosmotic Stress) perturbs cell function and stimulates cell responses by evoking MAPK cascades and activating AP-1 transcription complex resulting in alterations of gene expression, cell cycle arrest, and apoptosis. The results presented here demonstrate that Hyperosmotic Stress elicited increases in ATF-2 phosphorylation through a novel Polo-like kinase 3 (Plk3) pathway in human corneal epithelial (HCE) cells. We found in Hyperosmotic Stress-induced HCE cells that Plk3 transferred to the nuclear compartment and was colocalized with ATF-2 in nuclei. Kinase activity of Plk3 was significantly activated by Hyperosmotic stimulation. Further downstream, active Plk3 phosphorylated ATF-2 at the Thr-71 site in vivo and in vitro. Overexpression of Plk3 and its mutants enhanced Hyperosmotic Stress-induced ATF-2 phosphorylation. In contrast, suppression of Plk3 by knocking down Plk3 mRNA effectively diminished the effect of Hyperosmotic Stress-induced ATF-2 phosphorylation. The effect of Hyperosmotic Stress-induced activation of Plk3 on ATF-2 transcription factor function was also examined in CRE reporter-overexpressed HCE cells. Our results for the first time reveal that Hyperosmotic Stress can activate the Plk3 signaling pathway that subsequently regulates the AP-1 complex by directly phosphorylating ATF-2 independent from the effects of JNK and p38 activation.
Dietmar Kultz - One of the best experts on this subject based on the ideXlab platform.
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identification and pathway analysis of immediate Hyperosmotic Stress responsive molecular mechanisms in tilapia oreochromis mossambicus gill
Comparative Biochemistry and Physiology Part D: Genomics and Proteomics, 2006Co-Authors: Diego F Fiol, Stephanie Y Chan, Dietmar KultzAbstract:Abstract Salinity is a major environmental factor that strongly influences cellular and organismal function. We have used the euryhaline fish Oreochromis mossambicus to identify and annotate immediate Hyperosmotic Stress responsive molecular mechanisms and biological processes in gill epithelial cells. Using a suppression subtractive hybridization (SSH) approach, we have identified and cloned 20 novel immediate early genes whose mRNAs are induced in gill epithelial cells 4 h after transfer of fish from freshwater (FW) to seawater (SW). Full-length or partial sequences of open reading frames (ORFs) were obtained using the rapid amplification of cDNA ends (RACE) technique. Kinetics of induction was analyzed for all Hyperosmotic Stress-induced genes. Most genes show a robust transient increase in mRNA abundance characteristic of immediate early Stress response genes with peak levels observed between 2 and 8 h after seawater transfer. The newly identified genes were classified according to their sequence similarity with other vertebrate homologs and based on their predicted functions. Pathway analysis revealed that more than half of the identified immediate Hyperosmotic Stress genes interact closely within a cellular Stress response signaling network. Moreover, the 20 genes cluster together in six molecular processes that are rapidly activated in tilapia gills upon salinity transfer. These processes are (1) Stress response signal transduction, (2) compatible organic osmolyte accumulation, (3) energy metabolism, (4) lipid transport and cell membrane protection, (5) actin-based cytoskeleton dynamics, and (6) protein and mRNA stability. Our identification and analysis of a set of novel osmo-responsive tilapia genes provides insight into critical physiological processes and pathways constituting the Hyperosmotic Stress adaptation program in gill epithelial cells of euryhaline fishes.
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gadd45 proteins induce g2 m arrest and modulate apoptosis in kidney cells exposed to Hyperosmotic Stress
Journal of Biological Chemistry, 2004Co-Authors: Dietmar KultzAbstract:Abstract Gadd45 proteins are induced by hyperosmolality in renal inner medullary (IM) cells, but their role for cell adaptation to osmotic Stress is not known. We show that a cell line derived from murine renal IM cells responds to moderate Hyperosmotic Stress (540 mosmol/kg) by activation of G2/M arrest without significant apoptosis. If the severity of Hyperosmotic Stress exceeds the tolerance limit of this cell line (620 mosmol/kg) apoptosis is strongly induced. Using transient overexpression of ectopic Gadd45 proteins and simultaneous analysis of transfected versus non-transfected cells by laser-scanning cytometry, we were able to measure the effects of Gadd45 super-induction during hyperosmolality on G2/M arrest and apoptosis. Our results demonstrate that induction of all three Gadd45 isoforms inhibits mitosis and promotes G2/M arrest during moderate Hyperosmotic Stress but not in isosmotic controls. Furthermore, all three Gadd45 proteins are also involved in control of apoptosis during severe Hyperosmotic Stress. Under these conditions Gadd45γ induction strongly potentiates apoptosis. In contrast, Gadd45α/β induction transiently increases caspase 3/7 and annexin V binding before 12 h but inhibits later stages of apoptosis during severe hyperosmolality. These results show that Gadd45 isoforms function in common but also in distinct pathways during hyperosmolality and that their increased abundance contributes to the low mitotic index and protection of genomic integrity in cells of the mammalian renal inner medulla.
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Gadd45 Proteins Induce G2/M Arrest and Modulate Apoptosis in Kidney Cells Exposed to Hyperosmotic Stress
Journal of Biological Chemistry, 2004Co-Authors: Dietmar KultzAbstract:Abstract Gadd45 proteins are induced by hyperosmolality in renal inner medullary (IM) cells, but their role for cell adaptation to osmotic Stress is not known. We show that a cell line derived from murine renal IM cells responds to moderate Hyperosmotic Stress (540 mosmol/kg) by activation of G2/M arrest without significant apoptosis. If the severity of Hyperosmotic Stress exceeds the tolerance limit of this cell line (620 mosmol/kg) apoptosis is strongly induced. Using transient overexpression of ectopic Gadd45 proteins and simultaneous analysis of transfected versus non-transfected cells by laser-scanning cytometry, we were able to measure the effects of Gadd45 super-induction during hyperosmolality on G2/M arrest and apoptosis. Our results demonstrate that induction of all three Gadd45 isoforms inhibits mitosis and promotes G2/M arrest during moderate Hyperosmotic Stress but not in isosmotic controls. Furthermore, all three Gadd45 proteins are also involved in control of apoptosis during severe Hyperosmotic Stress. Under these conditions Gadd45γ induction strongly potentiates apoptosis. In contrast, Gadd45α/β induction transiently increases caspase 3/7 and annexin V binding before 12 h but inhibits later stages of apoptosis during severe hyperosmolality. These results show that Gadd45 isoforms function in common but also in distinct pathways during hyperosmolality and that their increased abundance contributes to the low mitotic index and protection of genomic integrity in cells of the mammalian renal inner medulla.