Drosophila Hsc70-4 is critical for neurotransmitter exocytosis in vivo.
AuthorsBronk P, Wenniger JJ, Dawson-Scully K, Guo X, Hong S, Atwood HL, Zinsmaier KE
JournalNeuron
PubMed ID11395008
'Previous in vitro studies of cysteine-string protein (CSP) imply a potential role for the clathrin-uncoating ATPase Hsc70 in exocytosis. We show that hypomorphic mutations in Drosophila Hsc70-4 (Hsc4) impair nerve-evoked neurotransmitter release, but not synaptic vesicle recycling in vivo. The loss of release can be restored by increasing external or ... More
A role for calcium in stabilizing transport vesicle coats.
Authors Ahluwalia J P; Topp J D; Weirather K; Zimmerman M; Stamnes M;
JournalJ Biol Chem
PubMed ID11435443
'Calcium has been implicated in regulating vesicle fusion reactions, but its potential role in regulating other aspects of protein transport, such as vesicle assembly, is largely unexplored. We find that treating cells with the membrane-permeable calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N'',N''-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM), leads to a dramatic redistribution of the vesicle ... More
Evaluation of activity of putative superoxide dismutase mimics. Direct analysis by stopped-flow kinetics.
AuthorsWeiss RH, Flickinger AG, Rivers WJ, Hardy MM, Aston KW, Ryan US, Riley DP
JournalJ Biol Chem
PubMed ID8226820
'By stopped-flow kinetic analysis, we have directly evaluated the superoxide dismutase (SOD) activity of a number of organic nitroxides and iron- and manganese-based complexes that have been attributed with having SOD activity based upon competition experiments with cytochrome c. In 60 mM HEPES buffer, pH 8.1, or 50 mM potassium ... More
Presynaptic calcium signals and transmitter release are modulated by calcium-activated potassium channels.
AuthorsRobitaille R, Charlton MP
JournalJ Neurosci
PubMed ID1370323
'The regulation of synaptic transmission by Ca(2+)-activated potassium (gKca) channels was investigated at the frog neuromuscular junction (nmj). Charybdotoxin (CTX), a blocker of certain types of gKca channels, induced a twofold increase of transmitter release. Similar results were obtained with purified natural toxin, synthetic toxin, and recombinant toxin. Apamin, a ... More
Phorbol ester promotes endocytosis by activating a factor involved in endosome fusion.
AuthorsAballay A, Stahl PD, Mayorga LS
JournalJ Cell Sci
PubMed ID10393811
'Previous studies indicate that a zinc- and phorbol ester-binding factor is necessary for in vitro endosome fusion and for the effect of Rab5 on endosome fusion. Rab5 is a small GTPase that regulates membrane fusion between early endosomes derived from either receptor-mediated endocytosis or fluid-phase endocytosis. In its GTP-bound form, ... More
'Synaptically released Zn2+ can enter and cause injury to postsynaptic neurons. Microfluorimetric studies using the Zn2+-sensitive probe, Newport green, examined levels of [Zn2+]i attained in cultured cortical neurons on exposure to N-methyl-D-asparte, kainate, or high K+ (to activate voltage-sensitive Ca2+ channels) in the presence of 300 microM Zn2+. Indicating particularly ... More
Apoptogenic ganglioside GD3 directly induces the mitochondrial permeability transition.
AuthorsKristal BS, Brown AM
JournalJ Biol Chem
PubMed ID10438487
'Early events in apoptotic cascades initiated by ceramides or by activation of the surface receptor CD95 (Fas/APO-1) include the formation of ganglioside GD3. GD3 appears to be both necessary and sufficient to propagate this lipid-mediated apoptotic pathway. Later events common to many apoptotic pathways include induction of the mitochondrial permeability ... More
Calcium binding to the cytosol and calcium extrusion mechanisms in intact synaptosomes and their alterations with aging.
AuthorsMartinez-Serrano A, Blanco P, Satrústegui J
JournalJ Biol Chem
PubMed ID1531657
'A simple method to measure cytosolic calcium binding in intact presynaptic nerve terminals (synaptosomes) from rat brain, which is based on the simultaneous determination of [Ca2+]i and total [45Ca2+] in quin2-loaded synaptosomes undergoing a switch from high- to low-calcium containing medium, is presented. Binding to the cytosolic compartment alone was ... More
Capacitative Ca2+ entry is closely linked to the filling state of internal Ca2+ stores: a study using simultaneous measurements of ICRAC and intraluminal [Ca2+].
AuthorsHofer AM, Fasolato C, Pozzan T
JournalJ Cell Biol
PubMed ID9442108
'ICRAC (the best characterized Ca2+ current activated by store depletion) was monitored concurrently for the first time with [Ca2+] changes in internal stores. To establish the quantitative and kinetic relationship between these two parameters, we have developed a novel means to clamp [Ca2+] within stores of intact cells at any ... More
Cellular activation by Ca2+ release from stores in the endoplasmic reticulum but not by increased free Ca2+ in the cytosol.
AuthorsStrayer DS, Hoek JB, Thomas AP, White MK
JournalBiochem J
PubMed ID10548531
'Ca(2+) release from intracellular stores and/or transmembrane influx can increase the cytosolic free Ca(2+) concentration ([Ca(2+)](i)). Such changes in [Ca(2+)](i) might transduce signals regulating transcription, motility, secretion, and so on. Surfactant secretagogues such as ATP and ionomycin stimulate the release and transmembrane influx of Ca(2+), both of which increase [Ca(2+)](i). ... More
Methylmercury-induced elevations in intrasynaptosomal zinc concentrations: an 19F-NMR study.
AuthorsDenny MF, Atchison WD
JournalJ Neurochem
PubMed ID8207443
'Methylmercury (MeHg) increases the concentration of intracellular Ca2+ ([Ca2+]i) and another endogenous polyvalent cation in both synaptosomes and NG108-15 cells. In synaptosomes, the elevation in [Ca2+]i was strictly dependent on extracellular Ca2+ (Ca2+e); similarly, in NG108-15 cells, a component of the elevations in [Ca2+]i was Ca2+e dependent. The MeHg-induced elevations ... More
Extracellular nucleotides mediate Ca2+ fluxes in J774 macrophages by two distinct mechanisms.
AuthorsGreenberg S, Di Virgilio F, Steinberg TH, Silverstein SC
JournalJ Biol Chem
PubMed ID3392016
'We have studied the effects of extracellular nucleotides on the cytosolic free calcium concentration [( Ca2+]i) in J774 macrophages using quin2 and indo-1 as indicator dyes. Micromolar quantities of ATP induced a biphasic increase in [Ca2+]i: a rapid and transient increase (peak I) which was due to mobilization of Ca2+ ... More
Rapid mobilization of cellular Ca2+ in bovine parathyroid cells evoked by extracellular divalent cations. Evidence for a cell surface calcium receptor.
AuthorsNemeth EF, Scarpa A
JournalJ Biol Chem
PubMed ID3558389
'The concentration of intracellular free Ca2+ ([Ca2+]i) was measured in dissociated bovine parathyroid cells using the fluorescent indicator quin-2 or fura-2. Small increases in the concentration of extracellular Ca2+ produced relatively slow, monophasic increases in [Ca2+]i in quin-2-loaded cells, but rapid and transient increases followed by lower, yet sustained (steady-state), ... More
Assessment of Fura-2 for measurements of cytosolic free calcium.
AuthorsRoe MW, Lemasters JJ, Herman B
JournalCell Calcium
PubMed ID2191782
'Fura-2 has become the most popular fluorescent probe with which to monitor dynamic changes in cytosolic free calcium in intact living cells. In this paper, we describe many of the currently recognized limitations to the use of Fura-2 in living cells and certain approaches which can circumvent some of these ... More
19F-NMR study of the effect of lead on intracellular free calcium in human platelets.
AuthorsDowd TL, Gupta RK
JournalBiochim Biophys Acta
PubMed ID1904777
'Lead has been shown to affect calcium homeostasis. However, there is no prior evidence to indicate an effect of low concentrations of lead in the environment (approximately 1 microM) on the intracellular free Ca2+ concentration in any human tissue. We have investigated the effect of lead on the intracellular free ... More
Intracellular calcium during chemotaxis of Dictyostelium discoideum: a new fura-2 derivative avoids sequestration of the indicator and allows long-term calcium measurements.
AuthorsSchlatterer C, Knoll G, Malchow D
JournalEur J Cell Biol
PubMed ID1322818
'During stimulation of Dictyostelium discoideum amoebae with the chemoattractant cAMP, extracellular calcium is taken up by the cells. The aim of this study was to determine the cytosolic free calcium concentration ([Ca++]i) during chemotaxis of Dictyostelium cells. In contrast to most vertebrate cells, three major drawbacks were encountered: 1) the ... More
Ca2+ and Zn2+ dependence of DNA synthesis in untransformed and in Ha-ras(val-12)-expressing NIH 3T3 cells.
AuthorsBack CJ, Sistonen L, Enkvist MO, Heikkilä JE, Akerman KE
JournalExp Cell Res
PubMed ID8359224
'The role of Ca2+ and Zn2+ in the initiation of DNA synthesis in NIH 3T3 fibroblasts and c-Ha-ras(val-12) oncoprotein-expressing (NIH 3T3) cells has been studied. Entrapment of the Ca2+ chelator, BAPTA (30 microM), into the cells totally blocked a serum-induced rise in cytosolic free Ca2+ ([Ca2+]i) as determined with fura-2. ... More
Metallothionein is part of a zinc-scavenging mechanism for cell survival under conditions of extreme zinc deprivation.
AuthorsSuhy DA, Simon KD, Linzer DI, O'Halloran TV
JournalJ Biol Chem
PubMed ID10092590
'Metallothionein (MT) is a small cysteine-rich protein thought to play a critical role in cellular detoxification of inorganic species by sequestering metal ions that are present in elevated concentrations. We demonstrate here that metallothionein can play an important role at the other end of the homeostatic spectrum by scavenging an ... More
Methylmercury increases intracellular concentrations of Ca++ and heavy metals in NG108-15 cells.
AuthorsHare MF, McGinnis KM, Atchison WD
JournalJ Pharmacol Exp Ther
PubMed ID8371160
'To determine if methylmercury (MeHg) increased [Ca++]i in intact neuron-like cells, we initiated studies using fluorescence microscopy of single NG108-15 cells preloaded with fura-2. Whereas at 0.5 microM, MeHg had no effect on the ratio of fura-2 fluorescence at 340/380 nm, at 2 and 5 microM it produced a biphasic ... More
The relationship between intracellular free iron and cell injury in cultured neurons, astrocytes, and oligodendrocytes.
AuthorsKress GJ, Dineley KE, Reynolds IJ
JournalJ Neurosci
PubMed ID12122047
'Iron is an essential element for cells but may also be an important cytotoxin. However, very little is known about iron transport, redox status, or toxicity specifically inside cells. In this study, we exploited the sensitivity of fura-2 to quenching by ferrous iron (Fe(2+)) to detect intracellular free iron ([Fe(2+)](i)) ... More
Measurement of intracellular free zinc in living cortical neurons: routes of entry.
'We used the ratioable fluorescent dye mag-fura-5 to measure intracellular free Zn2+ ([Zn2+]i) in cultured neocortical neurons exposed to neurotoxic concentrations of Zn2+ in concert with depolarization or glutamate receptor activation and identified four routes of Zn2+ entry. Neurons exposed to extracellular Zn2+ plus high K+ responded with a peak ... More
Active involvement of Ca2+ in mitotic progression of Swiss 3T3 fibroblasts.
AuthorsKao JP, Alderton JM, Tsien RY, Steinhardt RA
JournalJ Cell Biol
PubMed ID2114410
'Global Ca2+ transients have been observed to precede nuclear envelope breakdown and the onset of anaphase in Swiss 3T3 fibroblasts in 8% (vol/vol) FBS. The occurrence of these Ca2+ transients was dependent on intracellular stores. These Ca2+ transients could be (a) abolished by serum removal without halting mitosis, and (b) ... More
Calcium-sensitive fluorescent dyes can report increases in intracellular free zinc concentration in cultured forebrain neurons.
AuthorsCheng C, Reynolds IJ
JournalJ Neurochem
PubMed ID9832138
'High concentrations of Zn2+ are found in presynaptic terminals of excitatory neurons in the CNS. Zn2+ can be released during synaptic activity and modulate postsynaptic receptors, but little is known about the possibility that Zn2+ may enter postsynaptic cells and produce dynamic changes in the intracellular Zn2+ concentration ([Zn2+]i). We ... More
L-type calcium channels reduce ROS generation in cerebellar granule cells following kainate exposure.
AuthorsLeski ML, Hassinger LC, Valentine SL, Baer JD, Coyle JT
JournalSynapse
PubMed ID11746731
'Cerebellar granule cells (CGC) deprived of serum or trophic factors develop sensitivity to kainate neurotoxicity that is mediated by the alpha-amino-3-hydroxy-5-methyl-isoxazole proprionic acid (AMPA) subtypes of glutamate receptors (GluR). The L-type voltage-gated calcium channel (L-type VGCC) blocker nifedipine increases the potency of kainate 50-fold. Thus, one goal of this laboratory ... More
Effects of Ca2+ chelators on purified inositol 1,4,5-trisphosphate (InsP3) receptors and InsP3-stimulated Ca2+ mobilization.
AuthorsRichardson A, Taylor CW
JournalJ Biol Chem
PubMed ID8389355
'Changes in medium free [Ca2+] ([Ca2+]m) (< or = 1 microM) did not affect binding of [3H]InsP3 to inositol 1,4,5-trisphosphate (InsP3) receptors purified from cerebellum, but the chelators normally used to buffer [Ca2+]m inhibited InsP3 binding. 1,2-Bis(2-aminophenoxy)ethane-N,N,N'',N''-tetraacetic acid (BAPTA) (1 mM) fully and reversibly inhibited specific [3H]InsP3 (0.6 nM) binding; ... More
Multiple zinc binding sites in retinal rod cGMP phosphodiesterase, PDE6alpha beta.
AuthorsHe F, Seryshev AB, Cowan CW, Wensel TG
JournalJ Biol Chem
PubMed ID10787404
'The photoreceptor cGMP phosphodiesterase (PDE6) plays a key role in vertebrate vision, but its enzymatic mechanism and the roles of metal ion co-factors have yet to be determined. We have determined the amount of endogenous Zn(2+) in rod PDE6 and established a requirement for tightly bound Zn(2+) in catalysis. Purified ... More
Involvement of zinc in intracellular oxidant/antioxidant balance.
AuthorsParat MO, Richard MJ, Béani JC, Favier A
JournalBiol Trace Elem Res
PubMed ID9494057
'The effect of zinc (Zn) on cellular oxidative metabolism is complex and could be explained by multiple complementary interactions. In this study, we evaluated the impact of Zn on the pro-oxidant/antioxidant balance of HaCaT keratinocytes. Cells were submitted to a diffusible metal chelator able to induce intracellular Zn deprivation, TPEN, ... More
Clioquinol and pyrithione activate TRPA1 by increasing intracellular Zn2+.
AuthorsAndersson DA, Gentry C, Moss S, Bevan S,
JournalProc Natl Acad Sci U S A
PubMed ID19416844
'The antifungal and amoebicidal drug clioquinol (CQ) was withdrawn from the market when it was linked to an epidemic of subacute myelo-optico-neuropathy (SMON). Clioquinol exerts its anti-parasitic actions by acting as a Cu/Zn chelator and ionophore. Here we show that local injections of CQ produce mechanical hyperalgesia and cold hypersensitivity ... More
Intracellular zinc fluctuations modulate protein tyrosine phosphatase activity in insulin/insulin-like growth factor-1 signaling.
AuthorsHaase H, Maret W
JournalExp Cell Res
PubMed ID14644152
'Zinc is an effector of insulin/IGF-1 signaling and has insulinomimetic effects, the molecular basis of which is not understood. The present study establishes the capacity of zinc to inhibit protein tyrosine phosphatases (PTPs) as a cause for these effects and, moreover, demonstrates modulation of the insulin response by changes in ... More
Regulation of cytosolic Ca2+ in clonal human muscle cell cultures.
AuthorsSarabia V, Klip A
JournalBiochem Biophys Res Commun
PubMed ID2532882
'Human muscle cells were grown in culture and clonally selected for fusion potential. The concentration of cytoplasmic ionized calcium, [Ca2+]i, was measured in monolayers of fused myotubes using the Ca2+ indicator indo-1. The contributions of independent routes of Ca2+ influx and efflux to/from the cytoplasm on [Ca2+]i were investigated. The ... More
Metallothionein, nitric oxide and zinc homeostasis in vascular endothelial cells.
AuthorsPearce LL, Wasserloos K, St Croix CM, Gandley R, Levitan ES, Pitt BR
JournalJ Nutr
PubMed ID10801961
'Recent in vitro studies suggest that the oxidoreductive capacity of metal thiolate clusters in metallothionein (MT) contributes to intracellular zinc homeostasis. We used fluorescence-based techniques to address this hypothesis in intact endothelial cells, focusing on the contributory role of the important redox signaling molecule, nitric oxide. Microspectrofluorometry with Zinquin revealed ... More
Ionic regulation of endonuclease activity in PC12 cells.
AuthorsVillalba M, Ferrari D, Bozza A, Del Senno L, Di Virgilio F
JournalBiochem J
PubMed ID7487921
'We have investigated the Ca2+ dependency of DNA degradation into nucleosome-sized fragments in intact chromaffin-like PC12 cells and PC12 nuclear fractions. In intact cells we were unable to trigger DNA fragmentation by inducing either transient or sustained elevations of cytoplasmic Ca2+ ([Ca2+]i) with the Ca2+ ionophore ionomycin. On the contrary, ... More
Alpha-adrenoceptor-mediated increase in cytosolic free calcium in isolated cardiac myocytes.
AuthorsEckel J, Gerlach-Eskuchen E, Reinauer H
JournalJ Mol Cell Cardiol
PubMed ID1653361
'The effect of alpha-adrenoceptor stimulation on the concentration of cytosolic free calcium (Cai2+) was determined by measuring indo-l fluorescence in isolated ventricular cardiomyocytes from normal and streptozotocin-diabetic rat; 1.3 x 10(5) alpha 1-adrenoceptors per normal myocyte and an unaltered number of these receptors in cells from diabetic rats were detected ... More
Zinc-dependent multi-conductance channel activity in mitochondria isolated from ischemic brain.
AuthorsBonanni L, Chachar M, Jover-Mengual T, Li H, Jones A, Yokota H, Ofengeim D, Flannery RJ, Miyawaki T, Cho CH, Polster BM, Pypaert M, Hardwick JM, Sensi SL, Zukin RS, Jonas EA,
JournalJ Neurosci
PubMed ID16793892
'Transient global ischemia is a neuronal insult that induces delayed cell death. A hallmark event in the early post-ischemic period is enhanced permeability of mitochondrial membranes. The precise mechanisms by which mitochondrial function is disrupted are, as yet, unclear. Here we show that global ischemia promotes alterations in mitochondrial membrane ... More
Hypochlorous acid mobilizes intracellular zinc in isolated rat heart myocytes.
AuthorsTatsumi T, Fliss H
JournalJ Mol Cell Cardiol
PubMed ID8072005
'Neutrophil oxidants appear to cause contractile dysfunction in reperfused ischemic myocardium. This "reperfusion injury" may result from the intracellular mobilization of various metals. We examined the ability of hypochlorous acid (HOCl), a highly reactive neutrophil oxidant, to mobilize cellular zinc in cardiac tissue. To monitor cellular zinc concentrations, isolated rat ... More
Measurement of intracellular free zinc concentrations accompanying zinc-induced neuronal death.
AuthorsCanzoniero LM, Turetsky DM, Choi DW
JournalJ Neurosci
PubMed ID10493776
'Toxic zinc influx may contribute to selective neuronal death after transient global ischemia. We previously used the high-affinity (K(D) = 27 nm) fluorescent dye mag-fura-5 to detect initial increases in neuronal intracellular free Zn(2+) ([Zn(2+)](i)) associated with brief Zn(2+) exposure. Here we used the specific low-affinity Zn(2+) indicator Newport Green ... More
A macrocyclic zinc(II) fluorophore as a detector of apoptosis.
AuthorsKimura E, Aoki S, Kikuta E, Koike T
JournalProc Natl Acad Sci U S A
PubMed ID12646703
'Our originally designed dansylamidoethylcyclen 4 as a biomimetic Zn(2+)-selective fluorophore has been demonstrated to be a good detector of the apoptosis (induced by an anticancer agent, etoposide, and H(2)O(2)) in cancer cells such as HeLa and HL60 cells. The macrocyclic Zn(2+) ligand 4 (mostly as a deprotonated form) is cell-permeable ... More
Fluorescence measurements of free Ca2+ concentration in human erythrocytes using the Ca2+-indicator fura-2.
AuthorsDavid-Dufilho M, Montenay-Garestier T, Devynck MA
JournalCell Calcium
PubMed ID3191527
'We report here the use of the fluorescent Ca2+-chelator fura-2 to directly measure free Ca2+ concentration within intact human erythrocytes and the influence of viscosity on the fluorescence of this probe. The bright fluorescence of fura-2 has permitted the use of low concentrations of indicator and cells, thus minimizing the ... More
Oxidants increase intracellular free Zn2+ concentration in rabbit ventricular myocytes.
AuthorsTuran B, Fliss H, Désilets M
JournalAm J Physiol
PubMed ID9176274
'Oxidative stress may alter cardiac function by affecting intracellular free Zn2+ concentrations ([Zn2+]i). Rabbit ventricular myocytes loaded with fura 2 were used to fluorometrically measure resting [Zn2+]i (0.23 +/- 0.03 nM) and intracellular Ca2+ concentration ([Ca2+]i) (36 +/- 7 nM). Fluorescence quenching by the heavy metal chelator N,N,N'',N''-tetrakis(2-pyridylmethyl)ethylenediamine was used ... More
Aqueous dissolution of Alzheimer's disease Abeta amyloid deposits by biometal depletion.
AuthorsCherny RA, Legg JT, McLean CA, Fairlie DP, Huang X, Atwood CS, Beyreuther K, Tanzi RE, Masters CL, Bush AI
JournalJ Biol Chem
PubMed ID10438495
'Zn(II) and Cu(II) precipitate Abeta in vitro into insoluble aggregates that are dissolved by metal chelators. We now report evidence that these biometals also mediate the deposition of Abeta amyloid in Alzheimer''s disease, since the solubilization of Abeta from post-mortem brain tissue was significantly increased by the presence of chelators, ... More
Measurement of the matrix free Ca2+ concentration in heart mitochondria by entrapped fura-2 and quin2.
AuthorsLukács GL, Kapus A
JournalBiochem J
PubMed ID3435469
'A method was developed to monitor continuously the matrix free Ca2+ concentration ([Ca2+]m) of heart mitochondria by use of the fluorescent Ca2+ indicators, fura-2 and quin2. The acetoxymethyl esters of fura-2 and quin2 were accumulated in and hydrolysed by isolated mitochondria. An increase of the mitochondrial Ca content from 0.3 ... More
The calcium feedback signal in the phototransduction cascade of vertebrate rods.
AuthorsGray-Keller MP, Detwiler PB
JournalNeuron
PubMed ID7524559
'Intracellular free Ca (Cai) was measured in functionally intact rod outer segments in darkness and during light responses using the fluorescent Ca indicator Indo-dextran. In darkness, Cai was 554 +/- 25 nM (n = 28) for -85 +/- 2 pA of circulating dark current (Id) and declined in saturating light ... More
pH dependence and compartmentalization of zinc transported across plasma membrane of rat cortical neurons.
AuthorsColvin RA
JournalAm J Physiol Cell Physiol
PubMed ID11788343
'In this study, Zn(2+) transport in rat cortical neurons was characterized by successfully combining radioactive tracer experiments with spectrofluorometry and fluorescence microscopy. Cortical neurons showed a time-dependent and saturable transport of (65)Zn(2+) with an apparent affinity of 15-20 microM. (65)Zn(2+) transport was pH dependent and was decreased by extracellular acidification ... More
Intracellular Ca(2+) and Zn(2+) signals during monochloramine-induced oxidative stress in isolated rat colon crypts.
AuthorsCima RR, Dubach JM, Wieland AM, Walsh BM, Soybel DI
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID16002562
'During acute exacerbations of inflammatory bowel diseases, oxidants are generated through the interactions of bacteria in the lumen, activated granulocytes, and cells of the colon mucosa. In this study we explored the ability of one such class of oxidants, represented by monochloramine (NH(2)Cl), to serve as agonists of Ca(2+) and ... More
Glucose regulation of free Ca(2+) in the endoplasmic reticulum of mouse pancreatic beta cells.
AuthorsTengholm A, Hellman B, Gylfe E
JournalJ Biol Chem
PubMed ID10601240
'Free Ca(2+) was measured in organelles of individual mouse pancreatic beta cells loaded with the low affinity indicator furaptra. After removal of cytoplasmic indicator by controlled digitonin permeabilization the organelle Ca(2+) was located essentially in the endoplasmic reticulum (ER), >90% being sensitive to inhibition of sarco(endo)plasmic reticulum Ca(2+)-ATPases. The Ca(2+) ... More
Interference of lead with the calcium release activated calcium flux of osteoblast-like cells.
AuthorsWiemann M, Schirrmacher K, Büsselberg D
JournalCalcif Tissue Int
PubMed ID10594168
'Lead (Pb(2+)) tends to accumulate in bone from where it is released during bone resorption, thus leading to high local concentrations of Pb(2+) with the risk of cellular toxicity. We investigated the interference of Pb(2+) with the calcium release activated calcium influx (CRAC) of osteoblast-like (OBL) cells. CRAC was elicited ... More
Using quin2 in cell suspensions.
AuthorsRink TJ, Pozzan T
JournalCell Calcium
PubMed ID4016891
A new mitochondrial fluorescent zinc sensor.
AuthorsSensi SL, Ton-That D, Weiss JH, Rothe A, Gee KR
JournalCell Calcium
PubMed ID12887975
A novel cationic fluorescent zinc (Zn2+) indicator (RhodZin-3) with nanomolar affinity for Zn2+ has been synthesized. RhodZin-3 exhibits large pH-independent fluorescence increases in the orange region of the visible wavelength spectrum with increasing zinc concentrations, and no sensitivity to physiologically relevant Ca2+ concentrations. Experiments in neuronal cell cultures show that ... More
The thiol-modifying agent N-ethylmaleimide elevates the cytosolic concentration of free Zn(2+) but not of Ca(2+) in murine cortical neurons.
AuthorsGibon J, Tu P, Frazzini V, Sensi SL, Bouron A,
JournalCell Calcium
PubMed ID20667413
The membrane permeant alkylating agent N-ethylmaleimide (NEM) regulates numerous biological processes by reacting with thiol groups. Among other actions, NEM influences the cytosolic concentration of free Ca(2+) ([Ca(2+)]i). Depending on the cell type and the concentration used, NEM can promote the release of Ca(2+), affect its extrusion, stimulate or block ... More
Measurement of intracellular free zinc in living neurons.
AuthorsCanzoniero LM, Sensi SL, Choi DW
JournalNeurobiol Dis
PubMed ID9361304
Excessive Zn2+ influx has been implicated in the pathogenesis of neuronal death after global ischemia or prolonged seizures, but little is presently known about cellular regulation of intracellular free Zn2+ ([Zn2+]i). In large part, this is because the tools currently available for measuring [Zn2+]i are limited in comparison to those ... More
Critical evaluation of cytosolic calcium determination in resting muscle fibres from normal and dystrophic (mdx) mice.
AuthorsGailly P, Boland B, Himpens B, Casteels R, Gillis JM
JournalCell Calcium
PubMed ID8358771
The fluorescent probe Fura-2/AM was used to determine cytosolic free calcium concentration in soleus muscle and in isolated flexor digitorum brevis fibres. This required a precise calibration; therefore, each calibration parameter was studied in situ. The influence of the dye concentration on calcium measurements was also examined. This precise calibration ... More
Micromolar zinc affects endonucleolytic activity in hydrogen peroxide-mediated apoptosis.
AuthorsMarini M, Musiani D
JournalExp Cell Res
PubMed ID9521857
When damaged by hydrogen peroxide, peripheral blood lymphocytes undergo cell death by apoptosis in the absence of internucleosomal DNA cleavage, while, in the same cells, other apoptosis-inducing treatments bring DNA cleavage to completion. However, the formation of internucleosomal DNA fragments is readily obtained if cells are pretreated with a divalent ... More
Integrins and modulation of transmitter release from motor nerve terminals by stretch.
AuthorsChen BM, Grinnell AD
JournalScience
PubMed ID7667637
The stretch of a frog muscle within the physiological range can more than double the spontaneous and evoked release of neurotransmitter from its motor nerve terminals. Here, stretch enhancement of release was suppressed by peptides containing the sequence arginine-glycine-aspartic acid (RGD), which blocks integrin binding. Integrin antibodies also inhibited the ... More
Redox switch of hsp33 has a novel zinc-binding motif.
AuthorsJakob U, Eser M, Bardwell JC
JournalJ Biol Chem
PubMed ID10976105
The chaperone activity of the heat shock protein Hsp33 is regulated by reversible disulfide bond formation. Oxidized Hsp33 is active, and reduced Hsp33 is inactive. We show that zinc binding is essential for the function of this redox switch. Our results reveal that Hps33 contains a new, high affinity (K(a) ... More
Mechanism of reaction of a suggested superoxide-dismutase mimic, Fe(II)-N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine.
AuthorsIuliano L, Pedersen JZ, Ghiselli A, Praticò D, Rotilio G, Violi F
JournalArch Biochem Biophys
PubMed ID1309981
The interaction of a recently developed intracellular superoxide dismutase analogue, Fe(II)-N,N,N',N'-tetrakis(2- pyridylmethyl)ethylenediamine (Fe(II)-TPEN), with reactive oxygen species was investigated under in vitro conditions. The complex catalyzed the dismutation of enzyme- or radiolysis-generated superoxide with the production of H2O2; under steady-state conditions the equilibrium was strongly shifted toward Fe(III)-TPEN. Fe(II)-TPEN reacted ... 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
Detection of zinc translocation into apical dendrite of CA1 pyramidal neuron after electrical stimulation.
AuthorsSuh SW,
JournalJ Neurosci Methods
PubMed ID18929598
Translocation of the endogenous cation zinc from presynaptic terminals to postsynaptic neurons after brain insult has been implicated as a potential neurotoxic event. Several studies have previously demonstrated that a brief electrical stimulation is sufficient to induce the translocation of zinc from presynaptic vesicles into the cytoplasm (soma) of postsynaptic ... More
Superoxide dismutase mimics based on iron in vivo.
AuthorsNagano T, Hirano T, Hirobe M
JournalJ Biol Chem
PubMed ID2542303
Novel metal complexes, Fe(II)-tetrakis-N,N,N',N' (2-pyridylmethyl)ethylenediamine(Fe-TPEN) and Fe(III)-tris[N-(2-pyridylmethyl)-2-aminoethyl]amine (Fe-TPAA), catalyzed the dismutation of superoxide, and 0.8 microM Fe-TPEN and 7.5 microM Fe-TPAA were equivalent to 1 unit of superoxide dismutase (SOD) activity in the xanthine oxidase-cytochrome c assay. Addition of serum albumin had no effect on the activities of Fe-TPEN and ... More
Excitation-transcription coupling mediated by zinc influx through voltage-dependent calcium channels.
AuthorsAtar D, Backx PH, Appel MM, Gao WD, Marban E
JournalJ Biol Chem
PubMed ID7852308
Electrical activity initiates a program of selective gene expression in excitable cells. Although such transcriptional activation is commonly attributed to depolarization-induced changes in intracellular Ca2+, zinc represents a viable alternative given its prominent role as a cofactor in DNA-binding proteins coupled with evidence that Zn2+ can enter excitable cells in ... More
Tracing of labile zinc in live fish hepatocytes using FluoZin-3.
Intracellular zinc levels are homeostatically regulated and although most is bound, a pool of labile Zn(II) is present in cells. We show here that the zinc probe FluoZin-3 is useful to monitor zinc fluxes during fluorescent imaging of the trout hepatic cell line D11. Nuclei and bulk cytosol appeared to ... More
Antiviral activity of the zinc ionophores pyrithione and hinokitiol against picornavirus infections.
AuthorsKrenn BM, Gaudernak E, Holzer B, Lanke K, Van Kuppeveld FJ, Seipelt J,
JournalJ Virol
PubMed ID18922875
We have discovered two metal ion binding compounds, pyrithione (PT) and hinokitiol (HK), that efficiently inhibit human rhinovirus, coxsackievirus, and mengovirus multiplication. Early stages of virus infection are unaffected by these compounds. However, the cleavage of the cellular eukaryotic translation initiation factor eIF4GI by the rhinoviral 2A protease was abolished ... More
Zinc and 4-hydroxy-2-nonenal mediate lysosomal membrane permeabilization induced by H2O2 in cultured hippocampal neurons.
AuthorsHwang JJ, Lee SJ, Kim TY, Cho JH, Koh JY,
JournalJ Neurosci
PubMed ID18354014
Lysosomal membrane permeabilization (LMP) is implicated in cancer cell death. However, its role and mechanism of action in neuronal death remain to be established. In the present study, we investigate the function of cellular zinc in oxidative stress-induced LMP using hippocampal neurons. Live-cell confocal microscopy with FluoZin-3 fluorescence showed that ... More
Zinc ions cause the thimerosal-induced signal of fluorescent calcium probes in lymphocytes.
AuthorsHaase H, Hebel S, Engelhardt G, Rink L,
JournalCell Calcium
PubMed ID18977527
Most fluorescent probes for the investigation of calcium signaling also detect zinc ions. Consequently, changes in the intracellular zinc concentration could be mistaken for calcium signals. Thimerosal (TMS) is used as a calcium-mobilizing agent and we analyzed the contribution of zinc ions to the signal observed with fluorescent calcium probes ... More
Modulation of p53 protein conformation and DNA-binding activity by intracellular chelation of zinc.
AuthorsVerhaegh GW, Parat MO, Richard MJ, Hainaut P
JournalMol Carcinog
PubMed ID9537652
The transcription factor p53 controls the proliferation and survival of cells exposed to DNA damage. The specific DNA-binding domain of p53 (residues 102-292) has a complex tertiary structure that is stabilized by zinc. In this study, we showed that exposure of cultured cells to the membrane-permeable chelator N,N,N', N'-tetrakis(2-pyridylmethyl)ethylenediamine induced ... More
Zinc stabilizes the SecB binding site of SecA.
AuthorsFekkes P, de Wit JG, Boorsma A, Friesen RH, Driessen AJ
JournalBiochemistry
PubMed ID10213615
The molecular chaperone SecB targets preproteins to SecA at the translocation sites in the cytoplasmic membrane of Escherichia coli. SecA recognizes SecB via its carboxyl-terminal 22 aminoacyl residues, a highly conserved domain that contains 3 cysteines and 1 histidine residue that could potentially be involved in the coordination of a ... More
Calcium sequestration by isolated sarcoplasmic reticulum: real-time monitoring using ratiometric dual-emission spectrofluorometry and the fluorescent calcium-binding dye indo-1.
AuthorsO'Brien PJ
JournalMol Cell Biochem
PubMed ID2374546
This study demonstrates a simple, rapid, and reproducible microassay for real-time monitoring of Ca2(+)-sequestration by isolated sarcoplasmic reticulum (SR) using ratiometric dual-emission spectrofluorometry and the fluorescent calcium-binding dye indo-1. The SR membranes were isolated by differential centrifugation and suspended in a medium including Ca2+, indo-1, ATP and oxalate. As Ca2+ ... More
Zinc can increase the activity of protein kinase C and contributes to its binding to plasma membranes in T lymphocytes.
AuthorsCsermely P, Szamel M, Resch K, Somogyi J
JournalJ Biol Chem
PubMed ID3258866
In the primary structure of protein kinase C, the presence of a putative metal-binding site has been suggested (Parker, P.J., Coussens, L., Totty, N., Rhee, L., Young, S., Chen, E., Stabel, S., Waterfield, M.D., and Ullrich, A. (1986) Science 233, 853-859). In the present report, we demonstrate that the most ... More
Interaction between protein kinase C and regulatory ligand is enhanced by a chelatable pool of cellular zinc.
AuthorsForbes IJ, Zalewski PD, Giannakis C, Petkoff HS, Cowled PA
JournalBiochim Biophys Acta
PubMed ID2383592
At micromolar concentrations, zinc (Zn) and cadmium, but not other metals, greatly augmented binding of [3H]phorbol dibutyrate ([3H]PDBu) to protein kinase C (PKC) in cell homogenates and intact cells (in the presence of ionophore). Increased binding persisted for several hours. The heavy-metal chelating agent 1,10-phenanthroline completely reversed the increased [3H]PDBu ... More
Recombinant human tumour necrosis factor increases cytosolic free calcium in murine fibroblasts and stimulates inositol phosphate formation in L-M and arachidonic acid release in 3T3 cells.
AuthorsBouchelouche PN, Bendtzen K, Bak S, Nielsen OH
JournalCell Signal
PubMed ID2278808
Stimulation of murine L-M and 3T3 fibroblasts with human recombinant tumour necrosis factor (rTNF) resulted in an increase in the cytosolic free Ca2+ concentration ([Ca2+]i). In 3T3 cells rTNF also induced release and metabolization of arachidonic acid, whereas in L-M cells rTNF provoked rapid increases in the levels of inositol ... More
Intracellular free calcium rise triggers nuclear envelope breakdown in the sea urchin embryo.
AuthorsSteinhardt RA, Alderton J
JournalNature
PubMed ID3127727
Cytosolic free calcium has recently been implicated in the regulation of mitosis in plant and animal cells. We have previously found correlations between increases in the levels of intracellular free calcium [Ca2+]i and visible transitions of structure at nuclear envelope breakdown (NEBD) and the onset of anaphase during mitosis in ... More
Effect of age on K+-induced cytosolic Ca2+ changes in rat cortical synaptosomes.
AuthorsGiovannelli L, Pepeu G
JournalJ Neurochem
PubMed ID2746228
45Ca2+ uptake and cytosolic Ca2+ concentrations [( Ca2+]i) were measured in synaptosomes prepared from the cerebral cortex of 3-, 16-, and 24-month-old male Charles River Wistar rats. Electron-microscopic examination demonstrated no morphological differences between the synaptosomes prepared from 3- and 24-month-old rats. The fast phase of Ca2+ uptake was reduced ... More
Cytosolic free calcium and cell spreading decrease in fibroblasts from aged and Alzheimer donors.
AuthorsPeterson C, Ratan RR, Shelanski ML, Goldman JE
JournalProc Natl Acad Sci U S A
PubMed ID3464016
Aging and Alzheimer disease lead to alterations in calcium homeostasis. The concentration of cytosolic free calcium in cultured skin fibroblasts during aging and Alzheimer disease was determined with the calcium-sensitive fluorescent dyes quin-2 and fura-2. The Alzheimer donors showed a decline of 70% when compared to age-matched controls (P less ... More
Recruitment of CD40 and tumor necrosis factor receptor-associated factors 2 and 3 to membrane microdomains during CD40 signaling.
AuthorsHostager BS, Catlett IM, Bishop GA
JournalJ Biol Chem
PubMed ID10748139
Signals delivered to antigen-presenting cells through CD40 are critical for the activation of immune responses. Intracellular tumor necrosis factor (TNF) receptor-associated factors (TRAFs) are key elements of the signal transduction pathways of many TNF receptor family members, including CD40. We show for the first time that engagement of CD40 in ... More
Translational control of InsP3-induced chromatin condensation during the early cell cycles of sea urchin embryos.
AuthorsTwigg J, Patel R, Whitaker M
JournalNature
PubMed ID3127728
The cycles of DNA synthesis and chromatin condensation in dividing cells are controlled by signals from the cytoplasm. Changes in the concentration of free calcium (Cai) in the cytoplasm control a variety of cellular functions and it has thus been suggested that observed variations in Cai during the cell cycle ... More
Real-time imaging of nuclear permeation by EGFP in single intact cells.
AuthorsWei X, Henke VG, Strübing C, Brown EB, Clapham DE
JournalBiophys J
PubMed ID12547812
The NPC is the portal for the exchange of proteins, mRNA, and ions between nucleus and cytoplasm. Many small molecules (<10 kDa) permeate the nucleus by simple diffusion through the pore, but molecules larger than 70 kDa require ATP and a nuclear localization sequence for their transport. In isolated Xenopus ... More
TPEN, a Zn2+/Fe2+ chelator with low affinity for Ca2+, inhibits lamin assembly, destabilizes nuclear architecture and may independently protect nuclei from apoptosis in vitro.
AuthorsShumaker DK, Vann LR, Goldberg MW, Allen TD, Wilson KL
JournalCell Calcium
PubMed ID9601611
We used Xenopus egg extracts to examine the effects of TPEN, a chelator with strong affinities for Zn2+, Fe2+, and Mn2+, on nuclear assembly in vitro. At concentrations above 1 mM, TPEN blocked the assembly of the nuclear lamina and produced nuclei that were profoundly sensitive to stress-induced balloon-like 'shedding' ... More
The FYVE domain of early endosome antigen 1 is required for both phosphatidylinositol 3-phosphate and Rab5 binding. Critical role of this dual interaction for endosomal localization.
AuthorsLawe DC, Patki V, Heller-Harrison R, Lambright D, Corvera S
JournalJ Biol Chem
PubMed ID10652369
Early endosome antigen 1 (EEA1) is 170-kDa polypeptide required for endosome fusion. EEA1 binds to both phosphtidylinositol 3-phosphate (PtdIns3P) and to Rab5-GTP in vitro, but the functional role of this dual interaction at the endosomal membrane is unclear. Here we have determined the structural features in EEA1 required for binding ... More
Metal chelators reverse the action of hydrogen peroxide in rat luteal cells.
AuthorsMusicki B, Behrman HR
JournalMol Cell Endocrinol
PubMed ID8391493
In rat luteal cells hydrogen peroxide (H2O2) interferes with the functional coupling of the luteinizing hormone (LH) receptor and blocks cAMP-dependent progesterone production. To test if this action of H2O2 is dependent on the generation of hydroxyl radicals, the effects of metal chelators and hydroxyl radical scavengers were evaluated. The ... More
Endogenous heavy metal ions perturb fura-2 measurements of basal and hormone-evoked Ca2+ signals.
AuthorsSnitsarev VA, McNulty TJ, Taylor CW
JournalBiophys J
PubMed ID8842241
Using the membrane-permeant chelator of heavy metal ions, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene diamine (TPEN), we demonstrate that in pancreatic acinar cells, hepatocytes, and a variety of mammalian cell lines, endogenous heavy metal ions bind to cytosolic fura-2 causing basal cytosolic free [Ca2+] ([Ca2+]i) to be overestimated. TPEN had most effect in cells lightly ... More
Cytotoxic actions of the heavy metal chelator TPEN on NG108-15 neuroblastoma-glioma cells.
AuthorsAdler M, Shafer H, Hamilton T, Petrali JP
JournalNeurotoxicology
PubMed ID10499356
Effects of the heavy metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) were investigated on cytotoxicity in clonal NG108-15 neuroblastoma-glioma hybrid cells. Three min after addition of 100 microM TPEN, cells began to retract their neurites and lose their characteristic multipolar shape; by 3-4 hr of exposure, most cells detached from the substrate, either ... More
Fura-2 secretion and sequestration in macrophages. A blocker of organic anion transport reveals that these processes occur via a membrane transport system for organic anions.
Fura-2, loaded into J774.2 macrophages as the acetoxymethyl ester, is sequestered into intracellular vacuoles within 90 min after the beginning of the loading at 37 degrees C. The dye is also efficiently secreted from the cells. Sequestration and secretion of fura-2 reduce the accuracy of measurements of cytosolic free Ca2+ ... More
Mdm2 is a RING finger-dependent ubiquitin protein ligase for itself and p53.
AuthorsFang S, Jensen JP, Ludwig RL, Vousden KH, Weissman AM
JournalJ Biol Chem
PubMed ID10722742
Mdm2 has been shown to regulate p53 stability by targeting the p53 protein for proteasomal degradation. We now report that Mdm2 is a ubiquitin protein ligase (E3) for p53 and that its activity is dependent on its RING finger. Furthermore, we show that Mdm2 mediates its own ubiquitination in a ... More
Enhanced sarcoplasmic reticulum Ca(2+) release following intermittent sprint training.
AuthorsOrtenblad N, Lunde PK, Levin K, Andersen JL, Pedersen PK
JournalAm J Physiol Regul Integr Comp Physiol
PubMed ID10896877
To evaluate the effect of intermittent sprint training on sarcoplasmic reticulum (SR) function, nine young men performed a 5 wk high-intensity intermittent bicycle training, and six served as controls. SR function was evaluated from resting vastus lateralis muscle biopsies, before and after the training period. Intermittent sprint performance (ten 8-s ... More
Hepatoprotective effect of Fe-TPEN on carbon tetrachloride induced liver injury in rats.
AuthorsMoon JO, Park SK, Nagano T
JournalBiol Pharm Bull
PubMed ID9556161
Fe(II)-tetrakis-N,N,N',N'(2-pyridylmethyl) ethylenediamine (Fe-TPEN) catalyzes the dismutation of superoxide, and blocks the toxic effect of paraquat on Escherichia coli growth and survival. We examined antioxidative effects of Fe-TPEN on lipid peroxidation and t-butyl hydroperoxide induced cell damage. Fe-TPEN inhibited the FeSO4/H2O2 induced lipid peroxidation in the rat liver homogenates with an ... More
U box proteins as a new family of ubiquitin-protein ligases.
Authors Hatakeyama S; Yada M; Matsumoto M; Ishida N; Nakayama K I;
JournalJ Biol Chem
PubMed ID11435423
The U box is a domain of approximately 70 amino acids that is present in proteins from yeast to humans. The prototype U box protein, yeast Ufd2, was identified as a ubiquitin chain assembly factor that cooperates with a ubiquitin-activating enzyme (E1), a ubiquitin-conjugating enzyme (E2), and a ubiquitin-protein ligase ... More
Impaired sarcoplasmic reticulum Ca(2+) release rate after fatiguing stimulation in rat skeletal muscle.
AuthorsOrtenblad N, Sjøgaard G, Madsen K
JournalJ Appl Physiol
PubMed ID10904054
The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate to 66% that ... More
Visualization of labile zinc and its role in apoptosis of primary airway epithelial cells and cell lines.
AuthorsTruong-Tran AQ, Ruffin RE, Zalewski PD
JournalAm J Physiol Lung Cell Mol Physiol
PubMed ID11076807
The respiratory epithelium is vulnerable to noxious substances, resulting in the shedding of cells and decreased protection. Zinc (Zn), an antioxidant and cytoprotectant, can suppress apoptosis in a variety of cells. Here we used the novel Zn-specific fluorophore Zinquin to visualize and quantify labile intracellular Zn in respiratory epithelial cells. ... More
Hg2+ signaling in trout hepatoma (RTH-149) cells: involvement of Ca2+-induced Ca2+ release.
AuthorsBurlando B, Bonomo M, Fabbri E, Dondero F, Viarengo A
JournalCell Calcium
PubMed ID12887976
Mercury is a non-essential heavy metal affecting intracellular Ca2+ dynamics. We studied the effects of Hg2+ on [Ca2+]i in trout hepatoma cells (RTH-149). Confocal imaging of fluo-3-loaded cells showed that Hg2+ induced dose-dependent, sustained [Ca2+]i transient, triggered intracellular Ca2+ waves, stimulated Ca2+-ATPase activity, and promoted InsP3 production. The effect of ... More
A reevaluation of neuronal zinc measurements: artifacts associated with high intracellular dye concentration.
AuthorsDineley KE, Malaiyandi LM, Reynolds IJ
JournalMol Pharmacol
PubMed ID12181438
The emergence of zinc as a potent neurotoxin has prompted the development of techniques suitable for the measurement of intracellular free zinc ([Zn(2+)](i)) in cultured cells. Accordingly, a new family of Zn(2+)-sensitive fluorophores has become available. Using ionophore-induced elevations of [Zn(2+)](i) in cultured neurons, we measured [Zn(2+)](i)-induced changes in the ... More
Localized calcium signaling in multinucleated osteoclasts.
AuthorsXia SL, Ferrier J
JournalJ Cell Physiol
PubMed ID8698832
Localized intracellular Ca2+ ([Ca2+]i) pulses, fluctuations, and repetitive spikes were detected in multinucleated rabbit osteoclasts in the presence of serum and in response to calcitonin using the fluorescent calcium indicator fluo-3 and a laser scanning microscope. We observed that these [Ca2+], changes were often restricted within a region of the ... More
Cytosolic Ca2+ homeostasis in Ehrlich and Yoshida carcinomas. A new, membrane-permeant chelator of heavy metals reveals that these ascites tumor cell lines have normal cytosolic free Ca2+.
AuthorsArslan P, Di Virgilio F, Beltrame M, Tsien RY, Pozzan T
JournalJ Biol Chem
PubMed ID3919006
The intracellularly trappable fluorescent Ca2+ indicator quin-2 was used to measure free cytosolic Ca2+, [Ca2+]i, in the two highly dedifferentiated tumor cell lines, Ehrlich and Yoshida ascites carcinomas. It was found that these carcinoma cells can trap quin-2 similarly to normal cells, but [Ca2+]i was apparently significantly lower than in ... More
Basal intracellular free Mg2+ concentration in smooth muscle cells of guinea pig tenia cecum: intracellular calibration of the fluorescent indicator furaptra.
AuthorsTashiro M, Konishi M
JournalBiophys J
PubMed ID9414246
Longitudinal muscle strips dissected from tenia cecum of guinea pig were loaded with the Mg2+ indicator, furaptra, and the relation between the fluorescent ratio signal (R) and cytoplasmic free Mg2+ concentration ([Mg2+]i) was studied in smooth muscle cells at 25 degrees C. After the application of ionophores (4-bromo-A23187, monensin, and ... More
Induction of neuronal apoptosis by thiol oxidation: putative role of intracellular zinc release.
AuthorsAizenman E, Stout AK, Hartnett KA, Dineley KE, McLaughlin B, Reynolds IJ
JournalJ Neurochem
PubMed ID11032877
The membrane-permeant oxidizing agent 2,2'-dithiodipyridine (DTDP) can induce Zn(2+) release from metalloproteins in cell-free systems. Here, we report that brief exposure to DTDP triggers apoptotic cell death in cultured neurons, detected by the presence of both DNA laddering and asymmetric chromatin formation. Neuronal death was blocked by increased extracellular potassium ... More
DNA damage-induced [Zn(2+)](i) transients: correlation with cell cycle arrest and apoptosis in lymphoma cells.
Reactive changes in free intracellular zinc cation concentration ([Zn(2+)](i)) were monitored, using the fluorescent probe Zinquin, in human lymphoma cells exposed to the DNA-damaging agent VP-16. Two-photon excitation microscopy showed that Zinquin-Zn(2+) forms complexes in cytoplasmic vesicles. [Zn(2+)](i) increased in both p53(wt) (wild type) and p53(mut) (mutant) cells after exposure ... More
Regulation of ZiRF1 and basal SP1 transcription factor MRE-binding activity by transition metals.
AuthorsRemondelli P, Moltedo O, Leone A
JournalFEBS Lett
PubMed ID9373164
The metal-dependent activation of metallothionein (MT) genes requires the interaction of positive trans-activators (MRFs) with metal-regulatory (MRE) regions of MT promoters. In this report, we examined the role of transition metals in modulating the MRE-binding activities of two different MRE-binding proteins: the metal-regulated factor ZiRF1 and the basal factor SP1. ... More
Lead inhibits meso-2,3-dimercaptosuccinic acid induced calcium transients in cultured rhesus monkey kidney cells.
AuthorsPokorski PL, McCabe MJ, Pounds JG
JournalToxicology
PubMed ID10413185
Previously we have shown that meso-2,3-dimercaptosuccinic acid (DMSA, 15-500 microM) elicits concentration-dependent increases in intracellular calcium levels ([Ca2+]i) in untreated rhesus monkey kidney cells (LLC-MK2) (Pokorski et al., 1997, unpublished results). Little is known about the restorative effects of the chelating agent 2,3-dimercaptosuccinic acid on intracellular calcium homeostasis in the ... More
Pathways of cadmium influx in mammalian neurons.
AuthorsUsai C, Barberis A, Moccagatta L, Marchetti C
JournalJ Neurochem
PubMed ID10217297
The influx of the toxic cation Cd2+ was studied in fura 2-loaded rat cerebellar granule neurons. In cells depolarized with Ca2(+)-free, high-KCI solutions, the fluorescence emission ratio (R) increased in the presence of 100 microM Cd2(+). This increase was fully reversed by the Cd2+ chelator tetrakis(2-pyridylmethyl)ethylenediamine, indicating a cadmium influx ... More
Pyrrolidine dithiocarbamate induces bovine cerebral endothelial cell death by increasing the intracellular zinc level.
AuthorsKim CH, Kim JH, Xu J, Hsu CY, Ahn YS
JournalJ Neurochem
PubMed ID10098865
The antioxidant and metal-chelating effects of pyrrolidine dithiocarbamate (PDTC) have been extensively studied. PDTC prevents cell death induced by various insults. However, PDTC itself may cause cell death in selected experimental paradigms. PDTC induced bovine cerebral endothelial cell death. However, in serum-depleted medium, PDTC did not affect the cell viability, ... More
Correlation of apoptosis with change in intracellular labile Zn(II) using zinquin [(2-methyl-8-p-toluenesulphonamido-6-quinolyloxy)acetic acid], a new specific fluorescent probe for Zn(II).
AuthorsZalewski PD, Forbes IJ, Betts WH
JournalBiochem J
PubMed ID8257431
Zinquin [(2-methyl-8-p-toluenesulphonamido-6-quinolyloxy)-acetic acid], a membrane-permeant fluorophore specific for Zn(II), was used with spectrofluorimetry and video image analysis to reveal and quantify labile intracellular Zn. Zinquin labelled human chronic-lymphocytic-leukaemia lymphocytes, rat splenocytes and thymocytes with a weak diffuse fluorescence that was quenched when intracellular Zn was chelated with NNN'N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and ... More
Flow cytometric measurement of labile zinc in peripheral blood mononuclear cells.
AuthorsHaase H, Hebel S, Engelhardt G, Rink L
JournalAnal Biochem
PubMed ID16545333
Labile (i.e., free or loosely bound) zinc has the potential to modulate cellular function. Therefore, a flow cytometric assay for the measurement of labile zinc was developed to facilitate the investigation of the physiological roles of zinc. The zinc-sensitive fluorescent probe FluoZin-3 was used to quantify the amount of labile ... More