The plasma membrane calcium ATPase (PMCA) of neurones is electroneutral and exchanges 2 H+ for each Ca2+ or Ba2+ ion extruded

Thomas, R C

doi:10.1113/jphysiol.2008.162453

Cited by 62 publications

(43 citation statements)

References 43 publications

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“…1 determine PMCA kinetics. Ca 2ϩ -induced, mitochondrial-mediated changes in cytoplasmic pH or ATP levels (Wang et al 1994) could influence the ATP-dependent Ca 2ϩ -H ϩ exchange mediated by the PMCA (Thomas 2008). However, Ca 2ϩ taken up into the mitochondria following stimuli that evoke large Ca 2ϩ loads is eventually removed from the mitochondrial matrix (Wang and Thayer 1996;Werth and Thayer 1994), which would seem at odds with the idea that matrix Ca 2ϩ levels produced the graded slowing in PMCA-mediated Ca 2ϩ clearance.…”

Section: Stimulus-induced Time-dependent Changes In Pmca Function Arecontrasting

confidence: 43%

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons

Ferragamo¹,

Reinardy

Thayer³

2009

Journal of Neurophysiology

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Section: Stimulus-induced Time-dependent Changes In Pmca Function Arecontrasting

confidence: 43%

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons

Ferragamo¹,

Reinardy

Thayer³

2009

Journal of Neurophysiology

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“…However, during stimulation with 5 lM IM, these clearance pathways seem to be inhibited. PMCA activities are known to be inhibited by cytosolic acidification [21,22]. In this study, 5 lM IM was demonstrated to induce marked cytosolic acidification, which may inhibit PMCA.…”

Section: Discussionmentioning

confidence: 94%

HCO3 −-dependent transient acidification induced by ionomycin in rat submandibular acinar cells

et al. 2010

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Ionomycin (IM, 5 microM), which exchanges 1 Ca2+ for 1 H+, changed intracellular pH (pHi) with Ca2+ entry into rat submandibular acinar cells. IM-induced changes in pHi consisted of two components: the first is an HCO3--dependent transient pHi decrease, and the second is an HCO3--independent gradual pHi increase. IM (1 microM), which activates store-operated Ca2+ channels, induced an HCO3--dependent and transient pHi decrease without any HCO3--independent pHi increase. Thus, a gradual pHi increase was induced by the Ca2+/H+ exchange. The HCO3--dependent and transient pHi decrease induced by IM was abolished by acetazolamide, but not by methyl isobutyl amiloride (MIA) or diisothiocyanatostilbene disulfonate (DIDS), suggesting that the Na+/H+ exchange, the Cl-/HCO3- exchange, or the Na+-HCO3- cotransport induces no transient pHi decrease. Thapsigargin induced no transient pHi decrease. Thus, IM, not Ca2+ entry, reduced pHi transiently. IM reacts with Ca2+ to produce H+ in the presence of CO2/HCO3-: [H-IM]-+Ca2++CO2<-->{H-Ca-IM]+.HCO3-+H+. In this reaction, a monoprotonated IM reacts with Ca2+ and CO2 to produce an electroneutral IM complex and H+, and then H+ is removed from the cells via CO2 production. Thus, IM transiently decreased pHi. In conclusion, in rat submandibular acinar cells IM (5 microM) transiently reduces pHi because of its chemical characteristics, with HCO3- dependence, and increases pHi by exchanging Ca2+ for H+, which is independent of HCO3-.

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“…The Ca 2+ channels conductance is voltage dependent, while the conductance of the K + channel is Ca 2+ dependent but not voltage dependent. The Ca 2+ pump is modeled as electrically neutral, with a constant pump rate, comparable to what has been described for many Ca 2+ ATPases (Thomas, 2009); therefore, in the model the Ca 2+ ATPase does not contribute to the changes in membrane potential.…”

Section: A Mathematical Model To Recapitulate Ca 2+ Oscillationsmentioning

confidence: 99%

Buffering Capacity Explains Signal Variation in Symbiotic Calcium Oscillations

et al. 2012

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Legumes form symbioses with rhizobial bacteria and arbuscular mycorrhizal fungi that aid plant nutrition. A critical component in the establishment of these symbioses is nuclear-localized calcium (Ca 2+ ) oscillations. Different components on the nuclear envelope have been identified as being required for the generation of the Ca 2+ oscillations. Among these an ion channel, Doesn't Make Infections1, is preferentially localized on the inner nuclear envelope and a Ca 2+ ATPase is localized on both the inner and outer nuclear envelopes. Doesn't Make Infections1 is conserved across plants and has a weak but broad similarity to bacterial potassium channels. A possible role for this cation channel could be hyperpolarization of the nuclear envelope to counterbalance the charge caused by the influx of Ca 2+ into the nucleus. Ca 2+ channels and Ca 2+ pumps are needed for the release and reuptake of Ca 2+ from the internal store, which is hypothesized to be the nuclear envelope lumen and endoplasmic reticulum, but the release mechanism of Ca 2+ remains to be identified and characterized. Here, we develop a mathematical model based on these components to describe the observed symbiotic Ca 2+ oscillations. This model can recapitulate Ca 2+ oscillations, and with the inclusion of Ca 2+ -binding proteins it offers a simple explanation for several previously unexplained phenomena. These include long periods of frequency variation, changes in spike shape, and the initiation and termination of oscillations. The model also predicts that an increase in buffering capacity in the nucleoplasm would cause a period of rapid oscillations. This phenomenon was observed experimentally by adding more of the inducing signal.

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The plasma membrane calcium ATPase (PMCA) of neurones is electroneutral and exchanges 2 H⁺ for each Ca²⁺ or Ba²⁺ ion extruded

Cited by 62 publications

References 43 publications

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons

HCO3 −-dependent transient acidification induced by ionomycin in rat submandibular acinar cells

Buffering Capacity Explains Signal Variation in Symbiotic Calcium Oscillations

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The plasma membrane calcium ATPase (PMCA) of neurones is electroneutral and exchanges 2 H+ for each Ca2+ or Ba2+ ion extruded

Cited by 62 publications

References 43 publications

Ca2+-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca2+Pump in Hippocampal Neurons

Ca2+-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca2+Pump in Hippocampal Neurons

HCO3 −-dependent transient acidification induced by ionomycin in rat submandibular acinar cells

Buffering Capacity Explains Signal Variation in Symbiotic Calcium Oscillations

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The plasma membrane calcium ATPase (PMCA) of neurones is electroneutral and exchanges 2 H⁺ for each Ca²⁺ or Ba²⁺ ion extruded

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons

Ca²⁺-Dependent, Stimulus-Specific Modulation of the Plasma Membrane Ca²⁺Pump in Hippocampal Neurons