Effects of Adenophostin-A and Inositol-1,4,5-trisphosphate on Cl<sup>−</sup>Currents in<i>Xenopus laevis</i>Oocytes

Hc, Hartzell; Machaca, Khaled; Hirayama, Yoshiyuki

doi:10.1124/mol.51.4.683

Cited by 33 publications

(38 citation statements)

References 48 publications

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“…Utilizing Ca 2ϩ -dependent chloride currents as an indirect assay of [Ca 2ϩ ] i changes, both DeLisle et al (8) and Hartzell et al (9) observed activation of Ca 2ϩ entry with low concentrations of adenophostin A (ϳ100 pM (8) and ϳ50 pM (9)). DeLisle et al saw no evidence of Ca 2ϩ release with these concentrations, whereas Hartzell et al observed small chloride currents attributable to intracellular release.…”

Section: Fig 2 Effect Of (245)ip 3 (1 M) Microinjected Into An Oomentioning

confidence: 99%

“…Interestingly, two studies performed in Xenopus oocytes (8,9) suggested a site of action for adenophostin A in addition to that on intracellular Ca 2ϩ stores. In both studies, low concentrations of adenophostin A (Ͻ10 nM) appeared to preferentially activate the Ca 2ϩ entry process, although Hartzell et al (9), unlike DeLisle et al (8), could not find a clear dissociation between Ca 2ϩ release and Ca 2ϩ entry.…”

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confidence: 99%

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Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Bird

Takahashi²,

Tanzawa³

et al. 1999

Journal of Biological Chemistry

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Xenopus laevis oocytes have proven a useful model system for studying the inositol 1,4,5-trisphosphate ((1,4,5)IP 3 ) 1 -mediated calcium signaling system, providing insights into mechanisms of calcium oscillations (1) and capacitative Ca 2ϩ entry (2, 3). In many cell types, including Xenopus oocytes, activation of surface membrane receptors results in a biphasic Ca 2ϩ response composed of an initial mobilization of internally stored Ca 2ϩ , followed by entry of extracellular Ca 2ϩ (4). Much is known about the role of (1,4,5)IP 3 in mobilizing intracellular Ca 2ϩ , and a working model for the Ca 2ϩ entry process is described by the capacitative model (5, 6) according to which the depletion of intracellular (1,4,5)IP 3 -sensitive Ca 2ϩ stores signals the activation of plasma membrane calcium channels.Recently, a metabolite of Penicillium brevicompactum, adenophostin A, has been isolated and demonstrated to be an agonist for the (1,4,5)IP 3 receptor and to have a potency ϳ100-fold greater than that of (1,4,5)IP 3 (7). Interestingly, two studies performed in Xenopus oocytes (8, 9) suggested a site of action for adenophostin A in addition to that on intracellular Ca 2ϩ stores. In both studies, low concentrations of adenophostin A (Ͻ10 nM) appeared to preferentially activate the Ca (10) found that the diffusion of adenophostin A throughout the oocyte was considerably slower than that of IP 3 and concluded that this might explain the apparently diminished Ca 2ϩ release signal.In this study, we have used confocal microscopy to monitor directly spatial as well as temporal aspects of the effects of adenophostin A on intracellular Ca 2ϩ in Xenopus oocytes using the calcium-sensitive dye Calcium Green. Our results confirm that diffusion of adenophostin A throughout the oocytes is slower than that of IP 3 and additionally indicate that low concentrations of adenophostin A cause a confined mobilization of intracellular Ca 2ϩ that is capable of supporting spatially restricted Ca 2ϩ oscillations and spatially restricted Ca 2ϩ entry. This unique action of adenophostin A provides new insights into the role of IP 3 receptor binding in [Ca 2ϩ ] i oscillations and also into the spatial relationships between intracellular Ca 2ϩ release and activation of capacitative calcium entry. MATERIALS AND METHODS Isolation of Xenopus OocytesAdult albino female X. laevis (Xenopus One, Ann Arbor, MI) were anesthetized by hypothermia and decapitated. The ovaries were then removed and stored in ND96 buffer (96 mM NaCl, 2 mM KCl, 1 mM MgCl 2 , 1 mM CaCl 2 , and 5 mM HEPES (pH 7.6)). Stage V and VI oocytes were manually dissected free from the ovaries and follicles and maintained in ND96 buffer at 18°C until used.

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Section: Fig 2 Effect Of (245)ip 3 (1 M) Microinjected Into An Oomentioning

confidence: 99%

mentioning

confidence: 99%

Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Bird

Takahashi²,

Tanzawa³

et al. 1999

Journal of Biological Chemistry

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“…To test this possibility, we injected oocytes with high concentration of IP 3 (B2.5 mM), which results in rapid Ca 2 þ release similar to what is observed with ionomycin, and leads to a large I ClT following store depletion ( Supplementary Fig. 1E) 44,45 . We further treated cells with lysophosphatidic acid (LPA), which is known to activate G-protein coupled receptors and stimulate phospholipase C (PLC) to generate IP 3 in Xenopus oocytes 46 .…”

Section: Differential Activation Of Cacc By Ca 2 þ Mobilizing Agentsmentioning

confidence: 99%

“…These results argue that store depletion with IP 3 enhances the ability of CaCC to respond to Ca 2 þ flowing into the cell through SOCE. To confirm that this effect is specific to IP 3 and SOCE, we activated SOCE with the low-affinity Ca 2 þ chelator, TPEN, which is known to buffer free intraluminal ER Ca 2 þ thus simulating store depletion 44,45 . In a similar manner to thapsigargin and ionomycin, TPEN failed to generate the large I ClT observed following IP 3 df treatment (Fig.…”

Section: Differential Activation Of Cacc By Ca 2 þ Mobilizing Agentsmentioning

confidence: 99%

Mid-range Ca2+ signalling mediated by functional coupling between store-operated Ca2+ entry and IP3-dependent Ca2+ release

Courjaret

Machaca

2014

Nat Commun

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The versatility and universality of Ca 2 þ signals stem from the breadth of their spatial and temporal dynamics. Spatially, Ca 2 þ signalling is well studied in the microdomain scale, close to a Ca 2 þ channel, and at the whole-cell level. However, little is known about how local Ca 2 þ signals are regulated to specifically activate spatially distant effectors without a global Ca 2 þ rise. Here we show that an intricate coupling between the inositol 1,4,5 trisphosphate (IP 3 ) receptor, SERCA pump and store-operated Ca 2 þ entry (SOCE) allows for efficient mid-range Ca 2 þ signalling. Ca 2 þ flowing through SOCE is taken up into the ER lumen by the SERCA pump, only to be re-released by IP 3 Rs to activate distal Ca 2 þ -activated Cl À channels (CaCCs). This CaCC regulation contributes to setting the membrane potential of the cell. Hence functional coupling between SOCE, SERCA and IP 3 R limits local Ca 2 þ diffusion and funnels Ca 2 þ through the ER lumen to activate a spatially separate Ca 2 þ effector.

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“…Previous studies have shown this high affinity agonist for the InsP 3 receptor to be particularly effective at depleting agonist-sensitive internal Ca 2ϩ stores and maximally activating store-operated conductances including CRAC (26,27). Preincubation of the cells with either CspA or ascomycin (1 and 5 M, respectively, for 15-30 min) resulted in inward currents through the SOC channels measured at Ϫ80 mV with 400 nM internal Ca 2ϩ of 0.38 Ϯ 0.03 pA/pF (n ϭ 12) and 0.41 Ϯ 0.03 (n ϭ 5) respectively.…”

Section: Calcineurin and The Regulation Of Ca 2ϩ Entry 40092mentioning

confidence: 99%

Calcineurin Directs the Reciprocal Regulation of Calcium Entry Pathways in Nonexcitable Cells

Mignen

Thompson

Shuttleworth

2003

Journal of Biological Chemistry

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Effects of Adenophostin-A and Inositol-1,4,5-trisphosphate on Cl⁻Currents inXenopus laevisOocytes

Abstract: SUMMARY

Cited by 33 publications

References 48 publications

Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Mid-range Ca2+ signalling mediated by functional coupling between store-operated Ca2+ entry and IP3-dependent Ca2+ release

Calcineurin Directs the Reciprocal Regulation of Calcium Entry Pathways in Nonexcitable Cells

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Effects of Adenophostin-A and Inositol-1,4,5-trisphosphate on Cl−Currents inXenopus laevisOocytes

Abstract: SUMMARY

Cited by 33 publications

References 48 publications

Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Adenophostin A Induces Spatially Restricted Calcium Signaling in Xenopus laevis Oocytes

Mid-range Ca2+ signalling mediated by functional coupling between store-operated Ca2+ entry and IP3-dependent Ca2+ release

Calcineurin Directs the Reciprocal Regulation of Calcium Entry Pathways in Nonexcitable Cells

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Effects of Adenophostin-A and Inositol-1,4,5-trisphosphate on Cl⁻Currents inXenopus laevisOocytes