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Dong Zhou - One of the best experts on this subject based on the ideXlab platform.
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pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:OBJECTIVE To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed. METHODS The RGC-5 cell was differentiated in 0.1 mumol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The Protein expression levels were determined by using the Western blot method and PC2 activity analysis. RESULTS The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY Protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 Proteins gradually decreased whereas proCPE, CPE, and preproNPY Proteins gradually increased. CONCLUSION These results demonstrated that OGD inhibited the neuropeptide pro-Protein Processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-Proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-Protein Processing system might play a critical role in the ischemic stress of RGC-5 cells.
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retracted article pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:Objective To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed.
Songshan Tang - One of the best experts on this subject based on the ideXlab platform.
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pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:OBJECTIVE To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed. METHODS The RGC-5 cell was differentiated in 0.1 mumol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The Protein expression levels were determined by using the Western blot method and PC2 activity analysis. RESULTS The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY Protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 Proteins gradually decreased whereas proCPE, CPE, and preproNPY Proteins gradually increased. CONCLUSION These results demonstrated that OGD inhibited the neuropeptide pro-Protein Processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-Proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-Protein Processing system might play a critical role in the ischemic stress of RGC-5 cells.
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retracted article pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:Objective To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed.
C O Brostrom - One of the best experts on this subject based on the ideXlab platform.
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calcium dynamics and endoplasmic reticular function in the regulation of Protein synthesis implications for cell growth and adaptability
Cell Calcium, 2003Co-Authors: M A Brostrom, C O BrostromAbstract:The endoplasmic reticulum (ER) possesses the structural and functional features expected of an organelle that supports the integration and coordination of major cellular processes. Ca2+ sequestered within the ER sustains lumenal Protein Processing while providing a reservoir of the cation to support stimulus–response coupling in the cytosol. Release of ER Ca2+ sufficient to impair Protein Processing promotes ER stress and signals the “unfolded Protein response” (UPR). The association of the UPR with an acute suppression of mRNA translational initiation and a longer term up-regulation of ER chaperones and partial translational recovery is discussed. Regulatory sites in mRNA translation and the mechanisms responsible for the early and later phases of the UPR are reviewed. The regulatory significance of GRP78/BiP, a multifunctional, broad-specificity ER chaperone, in the coordination of ER Protein Processing with mRNA translation during acute and chronic ER stress is addressed. The relationship of ER stress to Protein misfolding in the cytoplasm is examined. Translational alterations in embryonic cardiomyocytes during treatments with various Ca2+-mobilizing, growth-promoting stimuli are described. The importance of ER Ca2+ stores, ER chaperones, and cytosolic-free Ca2+ in translational control and growth promotion by these stimuli is assessed. Some perspectives are provided regarding Ca2+ as an integrating factor in the generation or diversion of metabolic energy. Circumstances impacting upon cellular adaptability during exposure to growth stimuli or during stressful conditions that require rapid adjustments in ATP for continued viability are considered.
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regulation of translational initiation during cellular responses to stress
Progress in Nucleic Acid Research and Molecular Biology, 1997Co-Authors: C O Brostrom, M A BrostromAbstract:Chemicals and conditions that damage Proteins, promote Protein misfolding, or inhibit Protein Processing trigger the onset of protective homeostatic mechanisms resulting in “stress responses” in mammalian cells. Included in these responses are an acute inhibition of mRNA translation at the initiation step, a subsequent induction of various Protein chaperones, and the recovery of mRNA translation. Separate, but closely related, stress response systems exist for the endoplasmic reticulum (ER), relating to the induction of specific “glucose-regulated Proteins” (CRPs), and for the cytoplasm, pertaining to the induction of the “heat shock Proteins” (HSPs). Activators of the ER stress response system, including Ca2+-mobilizing and thiol-reducing agents, are discussed and compared to activators of the cytoplasmic stress system, such as arsenite, heavy metal cations, and oxidants. An emerging integrative literature is reviewed that relates Protein chaperones associated with cellular stress response systems to the coordinate regulation of translational initiation and Protein Processing. Background information is presented describing the roles of Protein chaperones in the ER and cytoplasmic stress response systems and the relationships of chaperones and Protein Processing to the regulation of mRNA translation. Hie role of chaperones in regulating eIF-2a kinase activities, eIF-2 cycling, and riboso-mal loading on mRNA is emphasized. Hie putative role of CRF78 in coupling rates of translation to Processing is modeled, and functional relationships between the HSF and CRP chaperone systems are discussed. © 1998 Academic press
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reversible phosphorylation of eukaryotic initiation factor 2α in response to endoplasmic reticular signaling
Molecular and Cellular Biochemistry, 1993Co-Authors: Christopher R Prostko, M A Brostrom, C O BrostromAbstract:Agents, such as EGTA, thapsigargin, and ionophore A23187, that mobilize sequestered Ca2+ from the endoplasmic reticulum (ER) or dithiothreitol (DTT) that compromises the oxidizing environment of the organelle, disrupt early Protein Processing and inhibit translational initiation. Increased phosphorylation of eIF-2 alpha (5-fold) and inhibition of eIF-2B activity (50%) occur in intact GH3 cells exposed to these agents for 15 min (Prostko et al. J. Biol. Chem. 267:16751-16754, 1992). Alterations in eIF-2 alpha phosphorylation and translational activity in response to EGTA were reversed by addition of Ca2+ in excess of chelator while responses to DTT were reversible by washing. Exposure for 3 h to either A23187 or DTT, previously shown to induce transcription-dependent translational recovery, resulted in dephosphorylation of eIF-2 alpha in a manner blocked by actinomycin D. Phosphorylation of eIF-2 alpha in response to A23187 or DTT was not prevented by conventional inhibitors of translation including cycloheximide, pactamycin, puromycin, or verrucarin. Prolonged inhibition of Protein synthesis to deplete the ER of substrates for Protein Processing resulted in increased eIF-2 alpha phosphorylation, decreased eIF-2B activity, and reduced monosome content that were indicative of time-dependent blockade; these inhibitors did not abolish polysomal content. Superphosphorylation of eIF-2 alpha occurred upon exposure of these preparations to either A23187 or DTT. Tunicamycin, an inhibitor of co-translational transfer of core oligosaccharide, provoked rapid phosphorylation of eIF-2 alpha and inhibition of translational initiation whereas sugar analog inhibitors of glycoProtein Processing did neither. A flow of processible Protein to the ER does not appear to be required for the phosphorylation of eIF-2 alpha in response to ER perturbants. We hypothesize that perturbation of the translocon, rather than suppression of Protein Processing, initiates the signal emanating from the ER culminating in eIF-2 alpha phosphorylation and translational repression.
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inhibition of Protein synthesis and early Protein Processing by thapsigargin in cultured cells
Biochemical Journal, 1993Co-Authors: W L Wong, M A Brostrom, G Kuznetsov, D Gmitteryellen, C O BrostromAbstract:Thapsigargin, a tumour-promoting sesquiterpene lactone, selectively inhibits the Ca(2+)-ATPase responsible for Ca2+ accumulation by the endoplasmic reticulum (ER). Mobilization of ER-sequestered Ca2+ to the cytosol and to the extracellular fluid subsequently ensues, with concomitant alteration of cellular functions. Thapsigargin was found to serve as a rapid, potent and efficacious inhibitor of amino acid incorporation in cultured mammalian cells. At concentrations mobilizing cell-associated Ca2+ to the extracellular fluid, thapsigargin provoked extensive inhibition of Protein synthesis within 10 min. The inhibition in GH3 pituitary cells involved the synthesis of almost all polypeptides, was not associated with increased cytosolic free Ca2+ concentration ([Ca2+]i), and was not reversed at high extracellular Ca2+. The transient rise in [Ca2+]i triggered by ionomycin was diminished by thapsigargin. Polysomes failed to accumulate in the presence of the drug, indicative of impaired translational initiation. With longer (1-3 h) exposures to thapsigargin, recovery of translational activity was observed accompanied by increased synthesis of the ER Protein glucose-regulated stress Protein 78 or immunoglobulin heavy-chain binding Protein ('GRP78/BiP') and its mRNA. Such inductions were comparable with those observed previously with Ca2+ ionophores which mobilize the cation from all intracellular sequestered sites. Actin mRNA concentrations declined significantly during such treatments. In HepG2 cells Processing and secretion of the glycoProtein alpha 1-antitrypsin were rapidly suppressed by thapsigargin. Ca2+ sequestered specifically by the ER is concluded to be essential for optimal Protein synthesis and Processing. These rapid effects of thapsigargin on mRNA translation, Protein Processing and gene expression should be considered when evaluating potential mechanisms by which this tumour promoter influences cellular events.
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phosphorylation of eukaryotic initiation factor eif 2 alpha and inhibition of eif 2b in gh3 pituitary cells by perturbants of early Protein Processing that induce grp78
Journal of Biological Chemistry, 1992Co-Authors: Christopher R Prostko, M A Brostrom, E M Malara, C O BrostromAbstract:Agents that mobilize sequestered intracellular Ca2+, including ionophore A23187, EGTA, thapsigargin, and Cbz-Gly-Phe-NH2 (where Cbz is benzyloxycarbonyl), or mild reducing agents, such as dithiothreitol, disrupt early Protein Processing in the endoplasmic reticulum (ER), inhibit translational initiation, and trigger the induction of GRP78, an ER resident Protein. Inhibition of translational initiation in response to acute treatment (15-30 min) of intact GH3 pituitary cells with each of these agents was accompanied by an average 5-fold increase in the amount of phosphorylated eukaryotic initiation factor (eIF) 2 alpha and a 50% reduction in eIF-2B activity. With continued exposure to A23187 (3 h) rates of amino acid incorporation partially recovered, eIF-2 alpha became dephosphorylated, and the inhibition of eIF-2B activity was abolished. These chronic effects were blocked by actinomycin D. Accumulating evidence that the ER may regulate rates of translational initiation through a signaling system altering the activity of eIF-2 is discussed.
Huanxin Liu - One of the best experts on this subject based on the ideXlab platform.
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pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:OBJECTIVE To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed. METHODS The RGC-5 cell was differentiated in 0.1 mumol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The Protein expression levels were determined by using the Western blot method and PC2 activity analysis. RESULTS The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY Protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 Proteins gradually decreased whereas proCPE, CPE, and preproNPY Proteins gradually increased. CONCLUSION These results demonstrated that OGD inhibited the neuropeptide pro-Protein Processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-Proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-Protein Processing system might play a critical role in the ischemic stress of RGC-5 cells.
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retracted article pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:Objective To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed.
Juanhui Zhang - One of the best experts on this subject based on the ideXlab platform.
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pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:OBJECTIVE To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed. METHODS The RGC-5 cell was differentiated in 0.1 mumol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The Protein expression levels were determined by using the Western blot method and PC2 activity analysis. RESULTS The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY Protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 Proteins gradually decreased whereas proCPE, CPE, and preproNPY Proteins gradually increased. CONCLUSION These results demonstrated that OGD inhibited the neuropeptide pro-Protein Processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-Proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-Protein Processing system might play a critical role in the ischemic stress of RGC-5 cells.
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retracted article pro Protein convertase 2 carboxypeptidase e mediated neuropeptide Processing of rgc 5 cell after in vitro ischemia
Neuroscience Bulletin, 2009Co-Authors: Songshan Tang, Juanhui Zhang, Huanxin Liu, Dong ZhouAbstract:Objective To observe the change of the neuropeptide pro-Protein Processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-Protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) Protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed.
