Search results for "Calcium"
showing 10 items of 1740 documents
Requirement of caveolae microdomains in extracellular signal-regulated kinase and focal adhesion kinase activation induced by endothelin-1 in primary…
1999
Endothelin-1 (ET-1) mitogenic activity in astrocytes is mediated by the activation of the extracellular signal-regulated kinase (ERK) pathway together with the Rho-dependent activation of the focal adhesion kinase (FAK) pathway. To clarify the mechanisms responsible for the coordinate activation of both pathways in the ET-1 signal propagation, the involvement of caveolae microdomains, suggested to play a role in signal transduction, was evaluated. In this study, it is reported that caveolae of primary astrocytes are enriched in endothelin receptor (ETB-R). Furthermore, signaling molecules such as the adaptor proteins Shc and Grb2, and the small G protein Rho, also reside within these microd…
Induction of collagenase-3 (MMP-13) expression in human skin fibroblasts by three-dimensional collagen is mediated by p38 mitogen-activated protein k…
1999
Collagenase-3 (matrix metalloproteinase-13, MMP-13) is a recently identified human MMP with an exceptionally wide substrate specificity and restricted tissue-specific expression. Here we show that MMP-13 expression is induced in normal human skin fibroblasts cultured within three-dimensional collagen gel resulting in production and proteolytic activation of MMP-13. Induction of MMP-13 mRNAs by collagen gel was potently inhibited by blocking antibodies against alpha1 and alpha2 integrin subunits and augmented by activating antibody against beta1 integrin subunit, indicating that both alpha1 beta1 and alpha2 beta1 integrins mediate the MMP-13-inducing cellular signal generated by three-dimens…
p42 MAPK phosphorylates 80 kDa MARCKS at Ser-113.
1996
Abstract It is demonstrated here that p42 MAPKinase (p42 MAPK) phosphorylates the M yristoylated A lanine- R ich C - K inase S ubstrate (MARCKS) at Ser-113. In permeabilised Swiss 3T3 cells activation of protein kinase C (PKC) leads to p42 MAPK activation, but only the protein kinase C sites in MARCKS become phosphorylated and not Ser-113. The mitogen platelet-derived growth factor (PDGF) elicits the same response. These results demonstrate that while Ser-113 is a substrate for p42 MAPK in vitro and can be phosphorylated in vivo as shown by Taniguchi et al. [(1994) J. Biol. Chem. 269, 18299–18302], its phosphorylation is not subject to acute regulation by p42 MAPK in Swiss 3T3 cells.
Dental stem cell signaling pathway activation in response to hydraulic calcium silicate-based endodontic cements: A systematic review of in vitro stu…
2020
Abstract Objective To present a qualitative synthesis of in vitro studies which analyzed human dental stem cell (DSC) molecular signaling pathway activation in response to hydraulic calcium silicate-based cements (HCSCs). Methods A systematic electronic search was performed in Medline, Scopus, Embase, Web of Science and SciELO databases on January 20 and last updated on March 20, 2020. In vitro studies assessing the implication of signaling pathways in activity related marker (gene/protein) expression and mineralization induced by HCSCs in contact with human DSCs were included. Results The search identified 277 preliminary results. After discarding duplicates, and screening of titles, abstr…
Thapsigargin-stimulated MAP kinase phosphorylation via CRAC channels and PLD activation: inhibitory action of docosahexaenoic acid.
2004
AbstractThis study was conducted on human Jurkat T-cells to investigate the role of depletion of intracellular Ca2+ stores in the phosphorylation of two mitogen-activated protein kinases (MAPKs), i.e. extracellular signal-regulated kinase (ERK) 1 and ERK2, and their modulation by a polyunsaturated fatty acid, docosahexaenoic acid (DHA). We observed that thapsigargin (TG) stimulated MAPK activation by store-operated calcium (SOC) influx via opening of calcium release-activated calcium (CRAC) channels as tyrphostin-A9, a CRAC channel blocker, and two SOC influx inhibitors, econazole and SKF-96365, diminished the action of the former. TG-stimulated ERK1/ERK2 phosphorylation was also diminished…
Protein-induced, previously unidentified twin form of calcite.
2007
Using single-crystal x-ray diffraction, we found a formerly unknown twin form in calcite crystals grown from solution to which a mollusc shell-derived 17-kDa protein, Caspartin, was added. This intracrystalline protein was extracted from the calcitic prisms of the Pinna nobilis shells. The observed twin form is characterized by the twinning plane of the (108)-type, which is in addition to the known four twin laws of calcite identified during 150 years of investigations. The established twin forms in calcite have twinning planes of the (001)-, (012)-, (104)-, and (018)-types. Our discovery provides additional evidence on the crucial role of biological macromolecules in biomineralization.
Protein mapping of calcium carbonate biominerals by immunogold
2007
The construction of metazoan calcium carbonate skeletons is finely regulated by a proteinaceous extracellular matrix, which remains embedded within the exoskeleton. In spite of numerous biochemical studies, the precise localization of skeletal proteins has remained for a long time as an elusive goal. In this paper, we describe a technique for visualizing shell matrix proteins on the surface of calcium carbonate crystals or within the biominerals. The technique is as follows: freshly broken pieces of biominerals or NaOCl then EDTA-etched polished surfaces are incubated with an antibody elicited against one matrix protein, then with a secondary gold-coupled antibody. After silver enhancement,…
Caspartin and calprismin, two proteins of the shell calcitic prisms of the Mediterranean fan mussel Pinna nobilis.
2005
We used the combination of preparative electrophoresis and immunological detection to isolate two new proteins from the shell calcitic prisms of Pinna nobilis, the Mediterranean fan mussel. The amino acid composition of these proteins was determined. Both proteins are soluble, intracrystalline, and acidic. The 38-kDa protein is glycosylated; the 17-kDa one is not. Ala, Asx, Thr, and Pro represent the dominant residues of the 38-kDa protein, named calprismin. An N-terminal sequence was obtained from calprismin. This sequence, which comprises a pattern of 4 cysteine residues, is not related to any known protein. The second protein, named caspartin, exhibits an unusual amino acid composition, …
MK801 blocks hypoxic blood-brain-barrier disruption and leukocyte adhesion.
2008
The aim of the present study was to examine the signaling pathways of hypoxia followed by reoxygenation (H/R)-induced disruption of the blood-brain-barrier (BBB) in a co-culture of astrocytes and brain endothelial cells (BEC) in vitro. We analyzed the possible stabilizing effect of MK801, a highly selective N-methyl-d-aspartate receptor (NMDAR) antagonist, on BBB integrity. Levels of reactive oxygen species (ROS), glutamate (Glut) release and monocyte adhesion were measured under normoxia and H/R. BBB integrity was monitored measuring the trans-endothelial electrical resistance (TEER). TEER values dropped under H/R conditions which was abolished by MK801. Glut release from astrocytes, but n…
Keyhole limpet hemocyanin (KLH), II: Characteristic reassociation properties of purified KLH1 and KLH2.
1997
Subunits of the two types of keyhole limpet hemocyanin (KLH1 and KLH2), purified by gel filtration chromatography and preparative polyacrylamide gel electrophoresis from Immucothel, have been used for macromolecular reassociation studies. In-vitro reassociation has been achieved with a standardized system using a Tris-saline stabilizing buffer at pH 7.4 containing 100 mM calcium and magnesium chloride at 4 degrees C. The relatively slow progress of reassociation has been monitored and the varying oligomeric forms of KLH1 and KLH2 produced have been studied by transmission electron microscopy, using specimens negatively stained with 5% ammonium molybdate containing 1% trehalose. Specimens ha…