We found that a high-strength elastomer was obtained by the heat elongation of a thermoplastic polyurethane (TPU) film consisting of a high content of crystalline hard segments (HS). The stress upturn continuously increased with the elongation ratio without a decrease in the strain recovery by heat elongation, i.e.
View Article and Find Full Text PDFDexamethasone (DEX), a potent glucocorticoid, increased the expression of T-cell death associated gene 8 (TDAG8), a proton-sensing G protein-coupled receptor, which is associated with the enhancement of acidic pH-induced cAMP accumulation, in peritoneal macrophages. We explored the role of increased TDAG8 expression in the anti-inflammatory actions of DEX. The treatment of macrophages with either DEX or acidic pH induced the cell death of macrophages; however, the cell death was not affected by TDAG8 deficiency.
View Article and Find Full Text PDFAtherosclerosis is a chronic inflammation disease characterized by acidic micromilieu and the accumulation of numerous bioactive lipid mediators, such as lysophosphatidic acid (LPA) and prostaglandins, in the atherosclerotic lesion. Chronic acidification induced various effects on vascular smooth muscle cells, but the molecular mechanisms underlying these effects remain unknown. In this study, we examine the role of proton-sensing ovarian cancer G protein-coupled receptor 1 (OGR1) in extracellular acidification-induced regulation of cyclooxygenase (COX)-2 induction, PGI(2) production, MAPK phosphatase (MKP)-1 expression, and plasminogen activator inhibitor (PAI)-1 expression and proliferation in human aortic smooth muscle cells (AoSMCs).
View Article and Find Full Text PDFGPR4, previously proposed as the receptor for sphingosylphosphorylcholine, has recently been identified as the proton-sensing G-protein-coupled receptor coupling to multiple intracellular signaling pathways, including the G(s)-protein/cAMP, G(12/13)-protein/Rho, and G(q)-protein/phospholipase C pathways. In the present study, we examined whether extracellularly located histidine residues of GPR4 sense extracellular protons and, if so, whether a certain histidine residue is critical for coupling to the single or multiple signaling pathway(s). We found that the mutation of histidine residue at 79, 165, or 269 from the N-terminal of GPR4 to phenylalanine shifted the half-maximal effective concentration (EC(50)) of proton-induced signaling activities to the right, including cAMP accumulation, SRE promoter activity reflecting Rho activity, and NFAT promoter activity reflecting phospholipase C signaling activity, without an appreciable change in the maximal activities.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2005
We previously demonstrated that cAMP-dependent protein kinase was reduced in the dendrites of MAP2-deficient mice. In this study, we compared the expression of various protein phosphatases (PPs) between wild-type and map2(-/-) dendrites. Kinase-associated phosphatase (KAP) was the only PP which showed difference between the two phenotypes: (1) the expression of KAP was reduced in map2(-/-) cortical dendrites, and (2) the amount of KAP bound to microtubules was reduced in map2(-/-) brains.
View Article and Find Full Text PDFCyclic adenosine monophosphate-dependent protein kinase (PKA) is involved in various biological functions in neurons. To investigate the subcellular localization of PKA, we stained cultured hippocampal neurons with anti-PKA catalytic subunit antisera. PKA catalytic subunit colocalized with microtubules (MTs) in dendrites as well as with the actin filaments (F-actin) in growth cones.
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