Inhibition of protein tyrosine phosphatase 1B by reactive oxygen species leads to maintenance of Ca2+ influx following store depletion in HEK 293 cells

Bogeski, Ivan; Bozem, M.; Sternfeld, Lutz; Hofer, Hans Werner; Schulz, Irene

doi:10.1016/j.ceca.2006.03.003

Cited by 51 publications

(35 citation statements)

References 38 publications

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“…Reverse exchange was then initiated by the addition of NaCl subsequent to the addition of 350 M CaCl 2 ; this concentration of Ca 2ϩ was chosen to promote maximal Ca 2ϩ influx through the exchanger while minimizing influx due to capacitative Ca 2ϩ entry following internal Ca 2ϩ store depletion (discussed below). Activation of capacitative Ca 2ϩ entry in HEK293 cells typically requires the addition of millimolar concentrations of Ca 2ϩ (29,30), consistent with our observations (data not shown). Another modification we made in subsequent experiments was related to the observation that fluorescence amplitude levels attained using the described gramicidin clamp method were significantly higher than those previously obtained with intact cells (22) 2ϩ -ATPase (PMCA), the sarco/endoplasmic reticulum Ca 2ϩ -ATPase (SERCA), and mitochondria.…”

Section: Assaying For Nckx2 Reverse Exchange and Dependence On Internsupporting

confidence: 82%

Na+-dependent Inactivation of the Retinal Cone/Brain Na+/Ca2+-K+ Exchanger NCKX2

Altimimi

Schnetkamp

2007

Journal of Biological Chemistry

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The SLC24 gene family Na ؉ /Ca 2؉ -K ؉ exchangers (NCKX) are bidirectional plasma membrane transporters whose main function is the extrusion of Ca 2؉ from the cytosol. In this study, we used human embryonic kidney 293 cells expressing human retinal cone/brain NCKX2 to examine its Na ؉ affinity and kinetic parameters of Ca 2؉ transport. With the use of the ionophore gramicidin to control alkali cation concentrations across the plasma membrane, application of high intracellular Na ؉ promoted large NCKX2-mediated increases in intracellular free Ca 2؉ in the 15-20 M range; this also resulted in inactivation of NCKX2 transport, the first description of this novel kinetic state. The affinity of NCKX2 for internal Na ؉ was found to be sigmoidal, with a Hill coefficient of 2.6 and K d ‫؍‬ 50 mM. The time-dependent (t1 ⁄ 2 ϳ 40s) inactivation of NCKX2 required high intracellular Na ؉ levels (K d > 50 mM) as well as high occupancy of the extracellular Ca 2؉ -binding site. Also reported are two residues whose substitution resulted in an increase in internal Na ؉ affinity to values of ϳ19 mM; these mutants also displayed enhanced inactivation, suggesting that inactivation requires binding of Na ؉ to its intracellular transport sites. These findings are the first report of a regulatory kinetic state of Ca 2؉ transport via NCKX2 Na ؉ /Ca 2؉ -K ؉ exchangers that may play a prominent role in regulation of Ca 2؉ extrusion in cellular environments such as neuronal synapses that experience frequent and dynamic Ca 2؉ fluxes.

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Section: Assaying For Nckx2 Reverse Exchange and Dependence On Internsupporting

confidence: 82%

Na+-dependent Inactivation of the Retinal Cone/Brain Na+/Ca2+-K+ Exchanger NCKX2

Altimimi

Schnetkamp

2007

Journal of Biological Chemistry

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“…However, these compounds are also very potent phosphatase inhibitors and oxidants could thus regulate SOCE via increased phosphorylation. Indeed, several studies showed that maintenance of SOCE can be modulated by redox induced changes in phosphorylation [14,178,179]. On the other hand, Ehring et al reported that vanadate compounds act in a similar way as thimerosal: They deplete the ER Ca 2+ stores via thiol oxidation and thus induce activation of I CRAC independently of any kinases or phosphatases [180].…”

Section: Reactive Oxygen Species Effects On Soce and Crac/orai Channelsmentioning

confidence: 99%

“…An increase in the mitochondrial Ca 2+ concentration leads to increased ROS production which then may affect other redox sensitive signaling pathways [12,[14][15][16][17]. Further information on mitochondrial ROS production can be found in references [18][19][20][21][22].…”

Section: Mitochondriamentioning

confidence: 99%

Redox regulation of calcium ion channels: Chemical and physiological aspects

et al. 2011

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a b s t r a c tReactive oxygen species (ROS) are increasingly recognized as second messengers in many cellular processes. While high concentrations of oxidants damage proteins, lipids and DNA, ultimately resulting in cell death, selective and reversible oxidation of key residues in proteins is a physiological mechanism that can transiently alter their activity and function. Defects in ROS producing enzymes cause disturbed immune response and disease.Changes in the intracellular free Ca 2+ concentration are key triggers for diverse cellular functions. Ca 2+ homeostasis thus needs to be precisely tuned by channels, pumps, transporters and cellular buffering systems. Alterations of these key regulatory proteins by reversible or irreversible oxidation alter the physiological outcome following cell stimulation. It is therefore necessary to understand which proteins are regulated and if this regulation is relevant in a physiological-and/or pathophysiological context. Because ROS are inherently difficult to identify and to measure, we first review basic oxygen redox chemistry and methods of ROS detection with special emphasis on electron paramagnetic resonance (EPR) spectroscopy. We then focus on the present knowledge of redox regulation of Ca 2+ permeable ion channels such as voltage-gated (CaV) Ca 2+ channels, transient receptor potential (TRP) channels and Orai channels.© 2011 Elsevier Ltd. All rights reserved. Basic redox chemistry of oxygenMany chemical processes are linked to the exchange of electrons between two or more molecular entities. The transfer of one (or more) electron(s) is associated with oxidation (loss of electron) and reduction (gain of electron) of the components. Such reactions are also known as redox reactions. The processes of reactive oxygen species (ROS) formation and elimination are exclusively of redox nature.Molecular oxygen is the precursor of all ROS. It contains two unpaired electrons in separate (antibonding) orbitals in its outer electron sphere and is thus, by definition, a radical. Radicals have at least one unpaired electron in their orbital system and usually show high reactivity; transition metal ions also may have unpaired electrons, but are not called radicals. Although having radical character, molecular oxygen is chemically rather inert (luckily!), because high * Corresponding authors at: Institut für Biophysik, Gebäude 58, Universität des Saarlandes, D-66421 Homburg/Saar, Germany. Tel.: +49 6841 1626453; fax: +49 6841 1626060.E-mail addresses: ivan.bogeski@uks.eu (I. Bogeski), barbara.niemeyer@uks.eu (B.A. Niemeyer).

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“…Some of them implicate a co-regulation between ROS and Ca 2+ metabolism [6,7]. ROS can be produced intracellularly as a result of different signalling cascades including the activation of plasma membrane bound receptors, store operated Ca 2+ influx or UV light exposure [5,6,8].…”

Section: Introductionmentioning

confidence: 99%

Redox properties of the calcium chelator Fura-2 in mimetic biomembranes

Gulaboski¹,

Pereira²,

Cordeiro³

et al. 2008

Cell Calcium

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Fura-2 is one of the most commonly used fluorescent dyes to analyze the cytosolic Ca 2+ concentration ([Ca 2+ ] i ) of living cells. Fura-2-dependent measurements of [Ca 2+ ] i are susceptible to changes of pH, reactive oxygen species concentration and membrane potential. Fura-2 is often loaded over the lipophilic cell membrane into the cytosol of a cell in its esterified form (Fura-2/AM) which is then cleaved by endogenous esterases. We have analyzed the electrochemical properties of Fura-2/AM and Fura-2 salt by cyclic voltammetry ("three-phase" and "thin-film" electrode methods). Using Fura-2/AM as a redox facilitator, we were able to mimic the transport of various ions across a lipophilic barrier. We show that Fura-2/AM in this biomimetic set-up can be reversibly oxidized in a single electrochemical step. Its redox reaction was highly proton sensitive in buffers with pH ≤ 6. At physiological pH of around 7.0, the oxidation of Fura-2/AM was coupled to an uptake of mono-anions across the liquid-liquid interface. The voltage-dependence of the redox cycle was sensitive to the free Ca 2+ concentration, either after de-esterification of Fura-2/AM, or when Fura-2 salt was used. The complex between Fura-2 and Ca 2+ ions is ionic (complexation occurs via the dissociated negative groups of Fura forms), while the redox transformations in Fura-2 occurs at the nitrogen atoms of the amino groups. Our results suggest that redox transformations of the Fura-2 forms do not affect the binding ability toward Ca 2+ ions and thus do not interfere with [Ca 2+ ] i measurements.

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Inhibition of protein tyrosine phosphatase 1B by reactive oxygen species leads to maintenance of Ca2+ influx following store depletion in HEK 293 cells

Abstract: Abstract

Cited by 51 publications

References 38 publications

Na+-dependent Inactivation of the Retinal Cone/Brain Na+/Ca2+-K+ Exchanger NCKX2

Na+-dependent Inactivation of the Retinal Cone/Brain Na+/Ca2+-K+ Exchanger NCKX2

Redox regulation of calcium ion channels: Chemical and physiological aspects

Redox properties of the calcium chelator Fura-2 in mimetic biomembranes

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