Cell membrane permeable esters of d-myo-inositol 1,4,5-trisphosphate

Dakin, Kenneth; Li, Wen Hong

doi:10.1016/j.ceca.2006.12.003

Cited by 44 publications

(44 citation statements)

References 36 publications

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“…1 B and C and 2 A; Movie S1), likely because the i-IP 3 resulting from photolysis is degraded more slowly than native IP 3 (17,20). Cells were essentially quiescent before photo-release of i-IP 3 , and after stimulation puffs continued for Ͼ60 s in the absence of extracellular Ca 2ϩ (n ϭ 7 cells), indicating that they are evoked by intracellular Ca 2ϩ liberation through IP 3 Rs.…”

Section: Resultsmentioning

confidence: 99%

Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells

Smith¹,

Parker

2009

Proc. Natl. Acad. Sci. U.S.A.

180

273

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The spatiotemporal patterning of Ca 2+ signals regulates numerous cellular functions, and is determined by the functional properties and spatial clustering of inositol trisphosphate receptor (IP 3 R) Ca 2+ release channels in the endoplasmic reticulum membrane. However, studies at the single-channel level have been hampered because IP 3 Rs are inaccessible to patch-clamp recording in intact cells, and because excised organelle and bilayer reconstitution systems disrupt the Ca 2+ -induced Ca 2+ release (CICR) process that mediates channel-channel coordination. We introduce here the use of total internal reflection fluorescence microscopy to image single-channel Ca 2+ flux through individual and clustered IP 3 Rs in intact mammalian cells. This enables a quantal dissection of the local calcium puffs that constitute building blocks of cellular Ca 2+ signals, revealing stochastic recruitment of, on average, approximately 6 active IP 3 Rs clustered within <500 nm. Channel openings are rapidly (≈10 ms) recruited by opening of an initial trigger channel, and a similarly rapid inhibitory process terminates puffs despite local [Ca 2+ ] elevation that would otherwise sustain Ca 2+ -induced Ca 2+ release indefinitely. Minimally invasive, nano-scale Ca 2+ imaging provides a powerful tool for the functional study of intracellular Ca 2+ release channels while maintaining the native architecture and dynamic interactions essential for discrete and selective cell signaling.

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Section: Resultsmentioning

confidence: 99%

Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells

Smith¹,

Parker

2009

Proc. Natl. Acad. Sci. U.S.A.

180

273

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“…In addition, DPAS (2 μM) was added to SAB in most experiments to resolve the dynamics of oscillatory insulin release better. To image [Ca 2+ ] i and Zn 2+ release concurrently, we loaded cells with both ZIMIR and Fura-2/AM (2 μM) in the presence of pluronic F-127 (1 g in 10 mL DMSO) (43). During loading, DMSO was kept below 0.5% and pluronic F-127 was less than 0.05%.…”

Section: Methodsmentioning

confidence: 99%

“…To image insulin release in islets, we labeled islets with ZIMIR (2 μM) in SAB buffer (3 mM glucose) for 20 min. Islets were then washed and imaged in SAB solution (with 10 μM forskolin) by CLSM using an LSM510 imaging system (Carl Zeiss) and a 40× oil immersion objective as described elsewhere (43).…”

Section: Methodsmentioning

confidence: 99%

Imaging dynamic insulin release using a fluorescent zinc indicator for monitoring induced exocytotic release (ZIMIR)

Chen

Bellomo

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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145

176

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Current methods of monitoring insulin secretion lack the required spatial and temporal resolution to adequately map the dynamics of exocytosis of native insulin granules in intact cell populations in three dimensions. Exploiting the fact that insulin granules contain a high level of Zn 2+ , and that Zn 2+ is coreleased with insulin during secretion, we have developed a fluorescent, cell surface-targeted zinc indicator for monitoring induced exocytotic release (ZIMIR). ZIMIR displayed a robust fluorescence enhancement on Zn 2+ chelation and bound Zn 2+ with high selectivity against Ca 2+ and Mg 2+ . When added to cultured β cells or intact pancreatic islets at low micromolar concentrations, ZIMIR labeled cells rapidly, noninvasively, and stably, and it reliably reported changes in Zn 2+ concentration near the sites of granule fusion with high sensitivity that correlated well with membrane capacitance measurement. Fluorescence imaging of ZIMIR-labeled β cells followed the dynamics of exocytotic activity at subcellular resolution, even when using simple epifluorescence microscopy, and located the chief sites of insulin release to intercellular junctions. Moreover, ZIMIR imaging of intact rat islets revealed that Zn 2+ /insulin release occurred largely in small groups of adjacent β cells, with each forming a "secretory unit." Concurrent imaging of ZIMIR and Fura-2 showed that the amplitude of cytosolic Ca 2+ elevation did not necessarily correlate with insulin secretion activity, suggesting that events downstream of Ca 2+ signaling underlie the cell-cell heterogeneity in insulin release. In addition to studying stimulation-secretion coupling in cells with Zn 2+ -containing granules, ZIMIR may find applications in β-cell engineering and screening for molecules regulating insulin secretion on high-throughput platforms.probe development | zinc imaging | hormone secretion assay

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“…3), indistinguishably and non-additively ( Fig. 3F) potentiate Flash photolysis of caged Ins(1,4,5)P 3 (ci-Ins(1,4,5)P 3 ) nondisruptively loaded into cells allows Ins(1,4,5)P 3 to be delivered directly to the cytosol (Dakin and Li, 2007). Photolysis of ciIns(1,4,5)P 3 caused transient increases in [Ca 2+ ] i , the amplitudes of which varied between cells (Fig.…”

Section: Camentioning

confidence: 99%

“…Flash photolysis of caged Ins(1,4,5)P 3 HEK cells grown on poly-L-lysine-coated, glass-bottomed culture dishes were loaded with ci-Ins(1,4,5)P 3 /PM (1 mM, 45 min) (Dakin and Li, 2007), and then with fluo-4/AM (2 mM) and ci-Ins(1,4,5)P 3 /PM (1 mM) for a further 45 min. After washing and incubation in HBS for a further 45 min, cells were imaged (20˚C) using an Olympus IX81 microscope equipped with a 406/1.35 NA objective.…”

Section: + ] Imentioning

confidence: 99%

Lysosomes shape Ins(1,4,5)P3-evoked Ca2+ signals by selectively sequestering Ca2+ released from the endoplasmic reticulum

López-Sanjurjo

Tovey

Prole

et al. 2013

Journal of Cell Science

123

111

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Summary Most intracellular Ca2+ signals result from opening of Ca 2+ channels in the plasma membrane or endoplasmic reticulum (ER), and they are reversed by active transport across these membranes or by shuttling Ca 2+ into mitochondria. Ca 2+ channels in lysosomes contribute to endo-lysosomal trafficking and Ca 2+ signalling, but the role of lysosomal Ca 2+ uptake in Ca 2+ signalling is unexplored. Inhibition of lysosomal Ca 2+ uptake by dissipating the H + gradient (using bafilomycin A 1 ), perforating lysosomal membranes (using glycyl-Lphenylalanine 2-naphthylamide) or lysosome fusion (using vacuolin) increased the Ca 2+ signals evoked by receptors that stimulate inositol 1,4,5-trisphosphate [Ins(1,4,5)P 3 ] formation. Bafilomycin A 1 amplified the Ca 2+ signals evoked by photolysis of caged Ins(1,4,5)P 3 or by inhibition of ER Ca 2+ pumps, and it slowed recovery from them. Ca 2+ signals evoked by store-operated Ca 2+ entry were unaffected by bafilomycin A 1 . Video-imaging with total internal reflection fluorescence microscopy revealed that lysosomes were motile and remained intimately associated with the ER. Close association of lysosomes with the ER allows them selectively to accumulate Ca 2+ released by Ins(1,4,5)P 3 receptors.

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Cell membrane permeable esters of d-myo-inositol 1,4,5-trisphosphate

Cited by 44 publications

References 36 publications

Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells

Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells

Imaging dynamic insulin release using a fluorescent zinc indicator for monitoring induced exocytotic release (ZIMIR)

Lysosomes shape Ins(1,4,5)P3-evoked Ca2+ signals by selectively sequestering Ca2+ released from the endoplasmic reticulum

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Cell membrane permeable esters of d-myo-inositol 1,4,5-trisphosphate

Cited by 44 publications

References 36 publications

Imaging the quantal substructure of single IP 3 R channel activity during Ca 2+ puffs in intact mammalian cells

Imaging the quantal substructure of single IP 3 R channel activity during Ca 2+ puffs in intact mammalian cells

Imaging dynamic insulin release using a fluorescent zinc indicator for monitoring induced exocytotic release (ZIMIR)

Lysosomes shape Ins(1,4,5)P3-evoked Ca2+ signals by selectively sequestering Ca2+ released from the endoplasmic reticulum

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Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells

Imaging the quantal substructure of single IP ₃ R channel activity during Ca ²⁺ puffs in intact mammalian cells