Signal transduction during exocytosis in Limulus polyphemus granulocytes.
AuthorsSolon E, Gupta AP, Gaugler R
JournalDev Comp Immunol
PubMed ID9016385
'Bacterial lipopolysaccharide (LPS)-induced exocytosis is one of the primary immune responses of the Limulus granulocyte (GR). Exocytosis can be mediated by guanine nucleotide-binding protein (G-protein)-linked surface receptors that activate phospholipase C (PLC) to produce inositol 1,4,5-triphosphate (IP3) and diacylglycerol (DAG). IP3 mobilizes intracellular Ca2+ ([Ca2+]i), which can lead to exocytosis. ... More
Kinetic studies of calcium-induced calcium release in cardiac sarcoplasmic reticulum vesicles.
AuthorsSánchez G, Hidalgo C, Donoso P
JournalBiophys J
PubMed ID12668440
'Fast Ca(2+) release kinetics were measured in cardiac sarcoplasmic reticulum vesicles actively loaded with Ca(2+). Release was induced in solutions containing 1.2 mM free ATP and variable free [Ca(2+)] and [Mg(2+)]. Release rate constants (k) were 10-fold higher at pCa 6 than at pCa 5 whereas Ryanodine binding was highest ... More
Phospholipid scramblase activation pathways in lymphocytes.
AuthorsWilliamson P, Christie A, Kohlin T, Schlegel RA, Comfurius P, Harmsma M, Zwaal RF, Bevers EM
JournalBiochemistry
PubMed ID11434775
'In erythrocytes and platelets, activation of a nonspecific lipid flipsite termed the scramblase allows rapid, bidirectional transbilayer movement of all types of phospholipids. When applied to lymphoid cells, scramblase assays reveal a similar activity, with scrambling rates intermediate between those seen in platelets and erythrocytes. Scrambling activity initiated in lymphoid ... More
Ca increase in secretory granules of stimulated mast cells.
AuthorsRaison S, Gillot I, Choine C, Pistone P, Pagnotta S, Laugier JP, Nicaise G
JournalCell Calcium
PubMed ID10598275
'The elemental content of rat peritoneal mast-cell secretory granules has been measured by X-ray micro-analysis. Two distinct categories of granules were analyzed: intact granules, seen in control samples, and spumous granules, corresponding to exocytosed granule matrices. The average Ca content of intact granules was found to be approximately equal to ... More
Cyclic ADP-ribose-gated Ca2+ release in sea urchin eggs requires an elevated.
AuthorsGuo X, Becker PL
JournalJ Biol Chem
PubMed ID9202011
'Cyclic ADP-ribose (cADPr) has been shown to release intracellular Ca2+ from sea urchin eggs and a variety of vertebrate cell types, although its mechanism of action remains elusive. We employed the caged version of cADPr to study the [Ca2+] transient kinetics in intact sea urchin eggs for insights into how ... More
Localization of the site of Ca2+ release at the level of a single sarcomere in skeletal muscle fibres.
'The development of mechanical force in skeletal muscle fibres is brought about by rapid increases in the intracellular calcium concentration (Ca2+ transients) which can be detected by optical methods. Local stimulation experiments and ultrastructural evidence suggest that, at a microscopic level, these Ca2+ transients are generated by the release of ... More
Calcium green-5N, a novel fluorescent probe for monitoring high intracellular free Ca2+ concentrations associated with glutamate excitotoxicity in cultured rat brain neurons.
AuthorsRajdev S, Reynolds IJ
JournalNeurosci Lett
PubMed ID7907171
We describe here the properties of calcium green-5N (CG5N), a novel Ca(2+)-sensitive fluorescent probe. CG5N binds Ca2+ with an affinity of 4.29 +/- 0.67 microM. Ca2+ binding is associated with a 14.7-fold increase in fluorescence. Mg2+ binds to CG5N with an affinity of 5 mM but produces a very small ... More
Glutamate-induced increases in intracellular free Mg2+ in cultured cortical neurons.
AuthorsBrocard JB, Rajdev S, Reynolds IJ
JournalNeuron
PubMed ID8104432
Intracellular free Mg2+ concentrations ([Mg2+]i) in single rat brain neurons were measured with the Mg(2+)-sensitive fluorescent dye magfura-2. Addition of glutamate with glycine raised [Mg2+]i from 1 to more than 11 mM compared with the resting concentration of 0.5 mM, an effect mediated by N-methyl-D-aspartate receptors. Most of the increase ... More
Fluorescent measurement of [Ca²?]c: basic practical considerations.
AuthorsSimpson AW,
JournalMethods Mol Biol
PubMed ID23007577
There is a vast array of dyes currently available for measurement of cytosolic calcium. These encompass single and dual excitation and single and dual emission probes. The choice of particular probe depends on the experimental question and the type of equipment to be used. It is therefore extremely difficult to ... More
Rotenone inhibits the mitochondrial permeability transition-induced cell death in U937 and KB cells.
AuthorsChauvin C, De Oliveira F, Ronot X, Mousseau M, Leverve X, Fontaine E
JournalJ Biol Chem
PubMed ID11527970
The permeability transition pore (PTP) is a mitochondrial inner membrane Ca(2+)-sensitive channel that plays a key role in different models of cell death. Because functional links between the PTP and the respiratory chain complex I have been reported, we have investigated the effects of rotenone on PTP regulation in U937 ... More
High-affinity calcium indicators underestimate increases in intracellular calcium concentrations associated with excitotoxic glutamate stimulations.
AuthorsStout AK, Reynolds IJ
JournalNeuroscience
PubMed ID10051219
We measured glutamate-stimulated increases in intracellular free Ca2+ concentrations ([Ca2+]i) in cultured rat forebrain neurons loaded with both a high- and a low-affinity Ca2+ indicator. In these dual-dye studies, the high-affinity indicators Fluo-3 and Fura-2 gave both qualitatively and quantitatively different results than the low-affinity indicators Mag-fura-2 and Calcium Green-5N. ... More
Three classes of ubiquinone analogs regulate the mitochondrial permeability transition pore through a common site.
To identify the structural features required for regulation of the mitochondrial permeability transition pore (PTP) by ubiquinone analogs (Fontaine, E., Ichas, F., and Bernardi, P. (1998) J. Biol. Chem. 40, 25734-25740), we have carried out an analysis with quinone structural variants. We show that three functional classes can be defined: ... More
InsP3 signaling induces pulse-modulated Ca2+ signals in the nucleus of airway epithelial ciliated cells.
AuthorsQuesada I, Verdugo P
JournalBiophys J
PubMed ID15792976
The phenomenology of nuclear Ca(2+) dynamics has experienced important progress revealing the broad range of cellular processes that it regulates. Although several agonists can mobilize Ca(2+) from storage in the nuclear envelope (NE) to the intranuclear compartment (INC), the mechanisms of Ca(2+) signaling in the nucleus still remain uncertain. Here ... More
Rapid coupling of calcium release to depolarization in Limulus polyphemus ventral photoreceptors as revealed by microphotolysis and confocal microscopy.
AuthorsUkhanov K, Payne R
JournalJ Neurosci
PubMed ID9030629
Microphotolysis and confocal microscopy were used to investigate the timing of calcium release and of the electrical response in Limulus polyphemus ventral photoreceptors. The fluorescent dyes Fluo-3 and Calcium Green-5N were used to monitor local Ca2+ elevations. Photolysis of caged inositol trisphosphate (InsP3) close to the plasma membrane of the ... More
Regulation of inositol trisphosphate receptors by luminal Ca2+ contributes to quantal Ca2+ mobilization.
AuthorsCombettes L, Cheek TR, Taylor CW
JournalEMBO J
PubMed ID8641274
The quantal behaviour of inositol trisphosphate (InsP3) receptors allows rapid graded release of Ca2+ from intracellular stores, but the mechanisms are unknown. In Ca2+-depleted stores loaded with Fura 2, InsP3 caused concentration dependent increases in the rates of fluorescence quench by Mn2+ that were unaffected by prior incubation with InsP3, ... More
Oligomeric interactions between phospholamban molecules regulate Ca-ATPase activity in functionally reconstituted membranes.
AuthorsYao Q, Chen LT, Li J, Brungardt K, Squier TC, Bigelow DJ
JournalBiochemistry
PubMed ID11371203
Phospholamban (PLB) is a major target of the beta-adrenergic cascade in the heart, and functions as an endogenous inhibitor of Ca-ATPase transport activity. To identify whether oligomeric interactions between PLB molecules are involved in regulating Ca-ATPase transport activity, we have investigated functional interactions between PLB and the Ca-ATPase in proteoliposomes ... More
Putative inositol 1,4,5-trisphosphate receptor localized to endoplasmic reticulum in Limulus photoreceptors.
AuthorsUkhanov K, Ukhanova M, Taylor CW, Payne R
JournalNeuroscience
PubMed ID9692740
Invertebrate microvillar photoreceptors utilize the phosphoinositide cascade to transduce light stimuli and inositol 1,4,5-trisphosphate is thought to be one of the messengers that triggers the electrical response by mobilizing intracellular stored calcium. To further characterize the role of the phosphoinositide signaling pathway in invertebrate phototransduction, we have examined the distribution ... More
Evaluation of glutathione-sensitive fluorescent dyes in cortical culture.
AuthorsTauskela JS, Hewitt K, Kang LP, Comas T, Gendron T, Hakim A, Hogan M, Durkin J, Morley P
JournalGlia
PubMed ID10797613
The sensitivity of six fluorophores to glutathione (GSH) was evaluated in living rat cortical neuronal/glial mixed cultures during the first 23 days in vitro (DIV). Four of the dyes require glutathione-S-transferase (GST) to form a fluorescent conjugate, potentially conferring specificity for GSH: these included t-butoxycarbonyl-Leu-Met-7-amino-4-chloromethylcoumarin (CMAC), 7-amino-4-chloromethylcoumarin (CMAC-blue), monochlorobimane (MCB), ... More