Mitochondrial modulation of Ca2+ -induced Ca2+ -release in rat sensory neurons.
AuthorsJackson JG, Thayer SA
JournalJ Neurophysiol
PubMed ID16760347
'Ca2+ -induced Ca2+ -release (CICR) from ryanodine-sensitive Ca2+ stores provides a mechanism to amplify and propagate a transient increase in intracellular calcium concentration ([Ca2+]i). A subset of rat dorsal root ganglion neurons in culture exhibited regenerative CICR when sensitized by caffeine. [Ca2+]i oscillated in the maintained presence of 5 mM ... More
The molecular basis of differential subcellular localization of C2 domains of protein kinase C-alpha and group IVa cytosolic phospholipase A2.
AuthorsStahelin RV, Rafter JD, Das S, Cho W
JournalJ Biol Chem
PubMed ID12531893
'The C2 domain is a Ca(2+)-dependent membrane-targeting module found in many cellular proteins involved in signal transduction or membrane trafficking. C2 domains are unique among membrane targeting domains in that they show a wide range of lipid selectivity for the major components of cell membranes, including phosphatidylserine and phosphatidylcholine. To ... More
Are intracellular ionic concentrations accessible using fluorescent probes? The example of Mag-indo-1.
AuthorsMorelle B, Salmon JM, Vigo J, Viallet P
JournalCell Biol Toxicol
PubMed ID7697494
'The study of the physicochemical properties of Mag-indo-1, a fluorescent probe used for intracellular magnesium measurements, has shown that in a biological environment the deprotonated form of this probe is in simultaneous equilibrium with a protonated form, a protein and a magnesium-bound form. The complex emission fluorescence spectrum emitted by ... More
AM-loading of fluorescent Ca2+ indicators into intact single fibers of frog muscle.
AuthorsZhao M, Hollingworth S, Baylor SM
JournalBiophys J
PubMed ID9168048
'The AM loading of a number of different fluorescent Ca2+ indicators was compared in intact single fibers of frog muscle. Among the 13 indicators studied, loading rates (the average increase in the fiber concentration of indicator per first 60 min of loading) varied approximately 100-fold, from approximately 3 microM/h to ... More
Regulation of intracellular free Mg2+ and contraction in single adult mammalian cardiac myocytes.
AuthorsSilverman HS, Di Lisa F, Hui RC, Miyata H, Sollott SJ, Hanford RG, Lakatta EG, Stern MD
JournalAm J Physiol
PubMed ID8304418
'Studies in isolated cardiac myocytes have increased our understanding of intracellular Ca2+ regulation. Because less is known about Mg2+ regulation, adult rat ventricular myocytes were loaded with the Mg(2+)-sensitive fluorescent probe mag-indo 1, and changes in intracellular Mg2+ concentration ([Mg2+]i) and cell length were examined under a variety of conditions. ... More
Mag-indo1 affinity for Ca(2+), compartmentalization and binding to proteins: the challenge of measuring Mg(2+) concentrations in living cells.
AuthorsPesco J, Salmon JM, Vigo J, Viallet P
JournalAnal Biochem
PubMed ID11237323
'A physicochemical study of the Mag-indo1 binding to Ca(2+) in solution showed that: (i) the characteristic fluorescence spectra of Ca(2+)-bound and Mg(2+)-bound Mag-indo1 are identical; (ii) two successive equilibria occur for increasing Ca(2+) concentrations; and (iii) the value of the dissociation constant of the first one, as determined by using ... More
Subcellular localization of glutamate-stimulated intracellular magnesium concentration changes in cultured rat forebrain neurons using confocal microscopy.
AuthorsCheng C, Reynolds IJ
JournalNeuroscience
PubMed ID10682704
'Glutamate can stimulate increases in intracellular magnesium concentration ([Mg2+]i) and induce neurotoxicity, both independent of Ca2+ changes. Although Mg2+ is essential within the cell, very little is known about how it is regulated, especially in neurons. Therefore we used the fluorescent indicator, magindo-1 and confocal microscopy to examine possible intracellular ... More
Fas-induced B cell apoptosis requires an increase in free cytosolic magnesium as an early event.
AuthorsChien MM, Zahradka KE, Newell MK, Freed JH
JournalJ Biol Chem
PubMed ID10066762
'Ligation of the Fas molecule expressed on the surface of a cell initiates multiple signaling pathways that result in the apoptotic death of that cell. We have examined Mg2+ mobilization as well as Ca2+ mobilization in B cells undergoing Fas-initiated apoptosis. Our results indicate that cytosolic levels of free (non-complexed) ... More
Measurement of intracellular magnesium concentration in 3T3 fibroblasts with the fluorescent indicator Mag-indo-1.
AuthorsMorelle B, Salmon JM, Vigo J, Viallet P
JournalAnal Biochem
PubMed ID8053551
'Mag-indo-1, a fluorescent probe for measuring intracellular magnesium concentration, was used in 3T3 fibroblasts with microspectrofluorometry. The complex emission fluorescence spectrum emitted by a single living cell was analyzed with a computerized method, making it possible to evaluate the contribution of each species of Mag-indo-1 to the total fluorescence. The ... More
Measurement of free [Ca2+] changes in agonist-sensitive internal stores using compartmentalized fluorescent indicators.
AuthorsHofer AM,
JournalMethods Mol Biol
PubMed ID16422202
This chapter provides a guide for the use of compartmentalized fluorescentdyes to measure free [Ca2+] in the agonist-sensitive internal store of single cells. The basic steps involve incubating cells with the AM-ester derivative of the appropriate dye (resulting in partitioning of the probe in both the cytoplasm and organelles), and ... More
The effect of pH on rate constants, ion selectivity and thermodynamic properties of fluorescent calcium and magnesium indicators.
AuthorsLattanzio FA, Bartschat DK
JournalBiochem Biophys Res Commun
PubMed ID2043105
Fluorescent calcium indicators fluo-3, fura-2 and indo-1, and fluorescent magnesium indicators mag-fura-2 (FURAPTRA) and mag-indo-1 were evaluated for the effects of pH on their association and dissociation rates, ion selectivity and thermodynamic properties. Calcium indicator affinities for Ca and Mg were reduced and the discrimination between Ca and Mg decreased ... More
Changes in free cytoplasmic magnesium following activation of human lymphocytes.
AuthorsRijkers GT, Griffioen AW
JournalBiochem J
PubMed ID8424782
Activation of lymphocytes with 10 microM ionomycin leads to a rapid increase in the concentration of free cytoplasmic calcium ([Ca2+]i) and, at a slower rate, also to an increase in the cytoplasmic free magnesium concentration ([Mg2+]i). The ionomycin-induced Mg(2+)-mobilization response is dependent on the influx of extracellular Ca2+. After receptor-mediated ... More
Cyclic Ca2+ changes in intracellular stores of gonadotropes during gonadotropin-releasing hormone-stimulated Ca2+ oscillations.
AuthorsTse FW, Tse A, Hille B
JournalProc Natl Acad Sci U S A
PubMed ID7937885
Gonadotropin-releasing hormone induces oscillatory release of Ca2+ from inositol trisphosphate-sensitive stores of gonadotropes. Simultaneously with electrophysiological measures of cytoplasmic [Ca2+], corresponding changes in [Ca2+] within intracellular stores were monitored with a fluorescent dye, mag-indo-1. Each cycle of oscillation released only 10% of the detectable stored Ca2+. Some Ca2+ was recovered ... More
TRPM7 activates m-calpain by stress-dependent stimulation of p38 MAPK and c-Jun N-terminal kinase.
TRPM7 is a Ca(2)(+)-permeant and Mg(2)(+)-permeant ion channel in possession of its own kinase domain. In a previous study, we showed that overexpression of the channel-kinase in HEK-293 cells produced cell rounding and loss of adhesion, which was dependent on the Ca(2+)-dependent protease m-calpain. The TRPM7-elicited change in cell morphology ... More
Calcium chelators induce apoptosis--evidence that raised intracellular ionised calcium is not essential for apoptosis.
AuthorsKluck RM, McDougall CA, Harmon BV, Halliday JW
JournalBiochim Biophys Acta
PubMed ID8086495
A moderate sustained rise in intracellular ionised calcium has been observed to be associated with apoptosis occurring in many experimental systems. The application of extracellular and intracellular chelators of calcium has been reported to produce a decrease in apoptosis, while the addition of calcium ionophores often increases apoptosis. These findings, ... More
Regulation of intracellular Mg2+ by superoxide in amnion cells.
AuthorsMasumoto N, Tasaka K, Mizuki J, Miyake A, Tanizawa O
JournalBiochem Biophys Res Commun
PubMed ID1310402
Changes of intracellular free Mg2+ concentration ([Mg2+]i) in human amnion cells induced by superoxide anion were determined using a highly Mg(2+)-sensitive fluorescent dye Mg(2+)-fura2 or Mg(2+)-indol. Superoxide anion, produced by addition of xanthine oxidase to hypoxanthine, induced decrease of [Mg2+]i. The decrease was significantly inhibited by an anion channel blocker, ... More
[Ca(2+)](i) oscillation frequency regulates agonist-stimulated NF-kappaB transcriptional activity.
AuthorsHu Q, Deshpande S, Irani K, Ziegelstein RC
JournalJ Biol Chem
PubMed ID10567364
In nonexcitable cells, stimulation by high agonist concentrations typically produces a biphasic increase in cytosolic Ca(2+) ([Ca(2+)](i)). This response is characterized by a transient initial increase because of intracellular Ca(2+) release followed by a sustained elevation which varies in amplitude depending on the nature of the stimulus. In contrast, low-level ... More
Intracellular Mg2+ inhibits the IP3-activated IK(Ca) in NG108-15 cells. [Why intracellular citrate can be useful for recording IK(Ca)]
AuthorsRobbins J, Cloues R, Brown DA
JournalPflugers Arch
PubMed ID1598189
Receptor-mediated formation of inositol 1,4,5-trisphosphate (IP3) can induce an outward Ca(2+)-activated K+ current [IK(Ca)] in some neural cells. We have investigated IK(Ca) activated by intracellular injections of IP3 in whole-cell patch-clamped neuroblastoma x glioma hybrid cells. The current could only be recorded reliably using citrate as the anion in the ... More
Measurements of intracellular Mg2+ concentration in mouse skeletal muscle fibers with the fluorescent indicator mag-indo-1.
AuthorsCsernoch L, Bernengo JC, Szentesi P, Jacquemond V
JournalBiophys J
PubMed ID9675196
Measurements of intracellular free magnesium concentration ([Mg2+]i) were performed on enzymatically isolated skeletal muscle fibers from mice, using the fluorescent ratiometric indicator mag-indo-1. An original procedure was developed to calibrate the dye response within the fibers: fibers were first permeabilized with saponin in the presence of a given extracellular magnesium ... More
NADPH oxidase activation increases the sensitivity of intracellular Ca2+ stores to inositol 1,4,5-trisphosphate in human endothelial cells.
Many stimuli that activate the vascular NADPH oxidase generate reactive oxygen species and increase intracellular Ca(2+), but whether NADPH oxidase activation directly affects Ca(2+) signaling is unknown. NADPH stimulated the production of superoxide anion and H(2)O(2) in human aortic endothelial cells that was inhibited by the NADPH oxidase inhibitor diphenyleneiodonium ... More
Measurement of matrix free Mg2+ concentration in rat heart mitochondria by using entrapped fluorescent probes.
1. The concentration of free Mg2+ ([Mg2+]m) within the matrix of isolated rat heart mitochondria was measured after loading of the mitochondria with the fluorescent Mg2+ indicators mag-indo-1 and mag-fura-2. No detectable change in total mitochondrial magnesium content occurred during loading with the indicators. Apparent Kd values for Mg2+ of ... More
Interaction of a protein, BSA, and a fluorescent probe, Mag-Indo-1, influence of EDTA and calcium on the equilibrium.
AuthorsRibou AC, Vigo J, Viallet P, Salmon JM
JournalBiophys Chem
PubMed ID10535100
Recent findings indicate that ion-chelator probes with tetracarboxylate structure bind proteins. It was suggested that these fluorescent probes are valuable tools to gain information on protein structure through the energy transfer from tryptophans to the bound probe. Here, the binding of the fluorescent probe Mag-Indo-1 to bovine serum albumin (BSA) ... More
On the use of fluorescent probes to estimate free Mg2+ in the matrix of heart mitochondria.
AuthorsJung DW, Chapman CJ, Baysal K, Pfeiffer DR, Brierley GP
JournalArch Biochem Biophys
PubMed ID8806704
The fluorescent probe furaptra shows increases and decreases in the concentration of free magnesium ion, [Mg2+], in the mitochondrial matrix with changes in total Mg2+ and ligand availability. The factors involved in the calibration of these fluorescence changes in terms of absolute [Mg2+] have been investigated. The affinity of furaptra ... More