Elementary and global aspects of calcium signalling.
TLDR
Using Ca2+ imaging techniques, the opening of individual channels has now been visualized and models have been proposed to explain how these elementary events are coordinated to generate the global Ca 2+ signals that regulate cellular activity.Abstract:
Calcium is a ubiquitous second messenger used to regulate a wide range of cellular processes. This role in signalling has to be conducted against the rigid homeostatic mechanisms that ensure that the resting level of Ca2+ is kept low (i.e. between 20 and 100 nmol l-1) in order to avoid the cytotoxic effects of a prolonged elevation of [Ca2+]. Cells have evolved a sophisticated signalling system based on the generation of brief pulses of Ca2+ which enables this ion to be used as a messenger, thus avoiding its toxic effects. Such Ca2+ spikes usually result from the coordinated release of Ca2+ from internal stores using either inositol 1,4,5-trisphosphate or ryanodine receptors. Using Ca2+ imaging techniques, the opening of individual channels has now been visualized and models have been proposed to explain how these elementary events are coordinated to generate the global Ca2+ signals that regulate cellular activity.read more
Citations
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Hierarchical organization of calcium signals in hepatocytes: from experiments to models.
TL;DR: This work reviews the various aspects of the spatio-temporal organization of cytosolic Ca(2+) in hepatocytes from the dual point of view provided by experiments and modeling, and focuses on the so-called elementary Ca( 2+) signals induced by low InsP(3) concentrations, leading to Ca (2+) rises having a spatial extent of a few microns.
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Purinergic signalling and intercellular Ca2+ wave propagation in the organ of Corti
TL;DR: Results indicate that intercellular calcium waves are a robust phenomenon that confers a significant ability for cell-cell communication in the mammalian cochlea and further ongoing research will reveal the roles that such Ca2+ waves play in the inner ear.
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Calcium as a versatile second messenger in the control of gene expression
TL;DR: The elevation of intracellular calcium is a major effector of stimulus‐induced physiological change in a variety of cell types and frequently involves the activation of gene expression.
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Selective coupling of type 6 adenylyl cyclase with type 2 IP3 receptors mediates direct sensitization of IP3 receptors by cAMP.
TL;DR: It is shown that PTH communicates with IP3R via “cAMP junctions” that allow local delivery of a supramaximal concentration of cAMP to IP2R, directly increasing their sensitivity to IP3, which is a robust binary switches that are digitally recruited by increasing concentrations of PTH.
Journal ArticleDOI
Compartmentalized signalling: Ca2+ compartments, microdomains and the many facets of Ca2+ signalling.
Alex Laude,Alec W.M. Simpson +1 more
TL;DR: This review discusses how Ca2+ responses are constructed from small quantal (elementary) events that have the potential to propagate to produce large pan‐cellular responses.
References
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Inositol trisphosphate and calcium signalling
TL;DR: Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle.
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Inositol trisphosphate, a novel second messenger in cellular signal transduction.
TL;DR: Diacylglycerol operates within the plane of the membrane to activate protein kinase C, whereas inositol trisphosphate is released into the cytoplasm to function as a second messenger for mobilizing intracellular calcium.
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A model for receptor-regulated calcium entry
TL;DR: A capacitative model is proposed for the mechanism by which activation of surface membrane receptors causes sustained Ca2+ entry into cells from the extracellular space, which allows forCa2+ release and Ca2-mobilization to be controlled by a single messenger, inositol (1,4,5) trisphosphate.
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Release of Ca2+ from a nonmitochondrial intracellular store in pancreatic acinar cells by inositol-1,4,5-trisphosphate.
TL;DR: It is reported here that micromolar concentrations of Ins1,4,5P3 release Ca2+ from a nonmitochondrial intracellular Ca2- store in pancreatic acinar cells, and the results strongly suggest that this is the same Ca1+ store that is released by acetylcholine.
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Calcium sparks: elementary events underlying excitation-contraction coupling in heart muscle
TL;DR: The calcium spark is the consequence of elementary events underlying excitation-contraction coupling and provides an explanation for both spontaneous and triggered changes in the intracellular calcium concentration in the mammalian heart.