scholarly journals Calcium signaling mediates mechanotransduction at the multicellular stage of Dictyostelium discoideum

2021 ◽  
Author(s):  
Hidenori Hashimura ◽  
Yusuke V. Morimoto ◽  
Yusei Hirayama ◽  
Masahiro Ueda
Keyword(s):  
Calcium Signaling ◽  
Dictyostelium Discoideum ◽  
Molecular Mechanisms ◽  
Calcium Release ◽  
Calcium Influx ◽  
Cytosolic Calcium ◽  
Calcium Signal ◽  
Mechanical Stimuli ◽  
Ip3 Receptor ◽  
Cellular Functions

Calcium acts as a second messenger and regulates cellular functions, including cell motility. In Dictyostelium discoideum, the cytosolic calcium level oscillates synchronously, and calcium signal waves propagate in the cell population during the early stages of development, including aggregation. At the unicellular phase, the calcium response through Piezo channels also functions in mechanosensing. However, calcium signaling dynamics during multicellular morphogenesis is still unclear. Here, live-imaging of cytosolic calcium levels revealed that calcium wave propagation, depending on cAMP relay, temporarily disappeared at the onset of multicellular body formation. Alternatively, the occasional burst of calcium signals and their propagation were observed in both anterior and posterior regions of migrating multicellular bodies. Calcium signaling in multicellular bodies occurred in response to mechanical stimulation. Both pathways, calcium release from the endoplasmic reticulum via IP3 receptor and calcium influx from outside the cell, were involved in calcium waves induced by mechanical stimuli. These show that calcium signaling works on mechanosensing in both the unicellular and multicellular phases of Dictyostelium using different molecular mechanisms during development.

scholarly journals The Role of Ca2+-NFATc1 Signaling and Its Modulation on Osteoclastogenesis

2020 ◽  
Vol 21 (10) ◽  
pp. 3646
Author(s):  
Jung Yun Kang ◽  
Namju Kang ◽  
Yu-Mi Yang ◽  
Jeong Hee Hong ◽  
Dong Min Shin
Keyword(s):  
Bone Loss ◽  
Calcium Signaling ◽  
Transient Receptor Potential ◽  
Calcium Influx ◽  
Osteoclast Differentiation ◽  
Receptor Potential ◽  
Cytosolic Calcium ◽  
Transient Receptor Potential Channels ◽  
Potential Channels ◽  
Transient Receptor

The increasing of intracellular calcium concentration is a fundamental process for mediating osteoclastogenesis, which is involved in osteoclastic bone resorption. Cytosolic calcium binds to calmodulin and subsequently activates calcineurin, leading to NFATc1 activation, a master transcription factor required for osteoclast differentiation. Targeting the various activation processes in osteoclastogenesis provides various therapeutic strategies for bone loss. Diverse compounds that modulate calcium signaling have been applied to regulate osteoclast differentiation and, subsequently, attenuate bone loss. Thus, in this review, we summarized the modulation of the NFATc1 pathway through various compounds that regulate calcium signaling and the calcium influx machinery. Furthermore, we addressed the involvement of transient receptor potential channels in osteoclastogenesis.

scholarly journals Sodium/Calcium Exchangers Selectively Regulate Calcium Signaling in Mouse Taste Receptor Cells

2010 ◽  
Vol 104 (1) ◽  
pp. 529-538 ◽  
Author(s):  
Steven A. Szebenyi ◽  
Agnieszka I. Laskowski ◽  
Kathryn F. Medler
Keyword(s):  
Calcium Release ◽  
Calcium Influx ◽  
Taste Receptor ◽  
Physiological Role ◽  
Cytosolic Calcium ◽  
Calcium Signals ◽  
Sodium Calcium ◽  
Signaling Mechanisms ◽  
Taste Cells ◽  
Mouse Taste

Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contribute to the termination of these signals have not been identified. In this study, we used calcium imaging to define the role of sodium-calcium exchangers (NCXs) in the termination of evoked calcium responses. We found that NCXs regulate the calcium signals that rely on calcium influx at the plasma membrane but do not significantly contribute to the calcium signals that depend on calcium release from internal stores. Our data indicate that this selective regulation of calcium signals by NCXs is due primarily to their location in the cell rather than to the differences in cytosolic calcium loads. This is the first report to define the physiological role for any of the CCMs utilized by taste cells to regulate their evoked calcium responses.

scholarly journals Calcium Influx and Signaling in Yeast Stimulated by Intracellular Sphingosine 1-Phosphate Accumulation

2001 ◽  
Vol 276 (15) ◽  
pp. 11712-11718 ◽  
Author(s):  
Christine J. Birchwood ◽  
Julie D. Saba ◽  
Robert C. Dickson ◽  
Kyle W. Cunningham
Keyword(s):  
Calcium Signaling ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Calcium Release ◽  
Calcium Influx ◽  
Yeast Cells ◽  
Signaling Mechanism ◽  
Sphingosine 1 Phosphate ◽  
Sphingosine Kinases ◽  
S1p Lyase

In mammalian cells, intracellular sphingosine 1-phosphate (S1P) can stimulate calcium release from intracellular organelles, resulting in the activation of downstream signaling pathways. The budding yeastSaccharomyces cerevisiaeexpresses enzymes that can synthesize and degrade S1P and related molecules, but their possible role in calcium signaling has not yet been tested. Here we examine the effects of S1P accumulation on calcium signaling using a variety of yeast mutants. Treatment of yeast cells with exogenous sphingosine stimulated Ca2+accumulation through two distinct pathways. The first pathway required the Cch1p and Mid1p subunits of a Ca2+influx channel, depended upon the function of sphingosine kinases (Lcb4p and Lcb5p), and was inhibited by the functions of S1P lyase (Dpl1p) and the S1P phosphatase (Lcb3p). The biologically inactive stereoisomer of sphingosine did not activate this Ca2+influx pathway, suggesting that the active S1P isomer specifically stimulates a calcium-signaling mechanism in yeast. The second Ca2+influx pathway stimulated by the addition of sphingosine was not stereospecific, was not dependent on the sphingosine kinases, occurred only at higher doses of added sphingosine, and therefore was likely to be nonspecific. Mutants lacking both S1P lyase and phosphatase (dpl1 lcb3double mutants) exhibited constitutively high Ca2+accumulation and signaling in the absence of added sphingosine, and these effects were dependent on the sphingosine kinases. These results show that endogenous S1P-related molecules can also trigger Ca2+accumulation and signaling. Several stimuli previously shown to evoke calcium signaling in wild-type cells were examined inlcb4 lcb5double mutants. All of the stimuli produced calcium signals independent of sphingosine kinase activity, suggesting that phosphorylated sphingoid bases might serve as messengers of calcium signaling in yeast during an unknown cellular response.

scholarly journals Molecular Mechanisms and Targets of Cyclic Guanosine Monophosphate (cGMP) in Vascular Smooth Muscles

2021 ◽  
Author(s):  
Aleš Fajmut
Keyword(s):  
Mathematical Models ◽  
Molecular Mechanisms ◽  
Soluble Guanylate Cyclase ◽  
Smooth Muscles ◽  
Cytosolic Calcium ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Vascular Smooth Muscles ◽  
Ip3 Receptor ◽  
Cl Channels

Molecular mechanisms and targets of cyclic guanosine monophosphate (cGMP) accounting for vascular smooth muscles (VSM) contractility are reviewed. Mathematical models of five published mechanisms are presented, and four novel mechanisms are proposed. cGMP, which is primarily produced by the nitric oxide (NO) dependent soluble guanylate cyclase (sGC), activates cGMP-dependent protein kinase (PKG). The NO/cGMP/PKG signaling pathway targets are the mechanisms that regulate cytosolic calcium ([Ca2+]i) signaling and those implicated in the Ca2+-desensitization of the contractile apparatus. In addition to previous mathematical models of cGMP-mediated molecular mechanisms targeting [Ca2+]i regulation, such as large-conductance Ca2+-activated K+ channels (BKCa), Ca2+-dependent Cl− channels (ClCa), Na+/Ca2+ exchanger (NCX), Na+/K+/Cl− cotransport (NKCC), and Na+/K+-ATPase (NKA), other four novel mechanisms are proposed here based on the existing but perhaps overlooked experimental results. These are the effects of cGMP on the sarco−/endo- plasmic reticulum Ca2+-ATPase (SERCA), the plasma membrane Ca2+-ATPase (PMCA), the inositol 1,4,5-trisphosphate (IP3) receptor channels type 1 (IP3R1), and on the myosin light chain phosphatase (MLCP), which is implicated in the Ca2+-desensitization. Different modeling approaches are presented and discussed, and novel model descriptions are proposed.

Prevention of Copper-Induced Calcium Influx and Cell Death by Prion-Derived Peptide in Suspension-Cultured Tobacco Cells

2009 ◽  
Vol 64 (5-6) ◽  
pp. 411-417 ◽  
Author(s):  
Tomoko Kagenishi ◽  
Ken Yokawa ◽  
Masaki Kuse ◽  
Minoru Isobe ◽  
François Bouteau ◽  
...  
Keyword(s):  
Cell Death ◽  
Calcium Influx ◽  
Plant Cells ◽  
Cytosolic Calcium ◽  
Calcium Signal ◽  
Channel Blockers ◽  
Dependent Manner ◽  
Copper Binding ◽  
Channel Opening ◽  
Nicotiana Tabacum L

Impact of copper on the oxidative and calcium signal transductions leading to cell death in plant cells and the effects of the copper-binding peptide derived from the human prion protein (PrP) as a novel plant-protecting agent were assessed using a cell suspension culture of transgenic tobacco (Nicotiana tabacum L., cell line BY-2) expressing the aequorin gene. Copper induces a series of biological and chemical reactions in plant cells including the oxidative burst reflecting the production of reactive oxygen species (ROS), such as hydroxyl radicals, and stimulation of calcium channel opening, allowing a transient increase in cytosolic calcium concentrations. The former was proven by the action of specifiC ROS scavengers blocking the calcium responses and the latter was proven by an increase in aequorin luminescence and its inhibition by specifi c channel blockers. Following these early events completed within 10 min, the development of copper-induced cell death was observed during additional 1 h in a dose-dependent manner. Addition of a synthetic peptide (KTNMKHMA) corresponding to the neurotoxic sequence in human PrP, prior to the addition of copper, effectively blocked both calcium influx and cell death induced by copper. Lastly, a possible mechanism of peptide action and future applications of this peptide in the protection of plant roots from metal toxicity or in favour of phytoremediation processes are discussed

scholarly journals Prolonged calcium influx after termination of light-induced calcium release in invertebrate photoreceptors

2009 ◽  
Vol 134 (3) ◽  
pp. 177-189 ◽  
Author(s):  
Maria del Pilar Gomez ◽  
Enrico Nasi
Keyword(s):  
Calcium Release ◽  
Calcium Influx ◽  
Alternative Pathway ◽  
Membrane Conductance ◽  
Receptor Potential ◽  
Cytosolic Calcium ◽  
Slow Inward Current ◽  
Alternative Mechanism ◽  
Large Size ◽  
Gradual Development

In microvillar photoreceptors, light stimulates the phospholipase C cascade and triggers an elevation of cytosolic Ca2+ that is essential for the regulation of both visual excitation and sensory adaptation. In some organisms, influx through light-activated ion channels contributes to the Ca2+ increase. In contrast, in other species, such as Lima, Ca2+ is initially only released from an intracellular pool, as the light-sensitive conductance is negligibly permeable to calcium ions. As a consequence, coping with sustained stimulation poses a challenge, requiring an alternative pathway for further calcium mobilization. We observed that after bright or prolonged illumination, the receptor potential of Lima photoreceptors is followed by the gradual development of an after-depolarization that decays in 1–4 minutes. Under voltage clamp, a graded, slow inward current (Islow) can be reproducibly elicited by flashes that saturate the photocurrent, and can reach a peak amplitude in excess of 200 pA. Islow obtains after replacing extracellular Na+ with Li+, guanidinium, or N-methyl-d-glucamine, indicating that it does not reflect the activation of an electrogenic Na/Ca exchange mechanism. An increase in membrane conductance accompanies the slow current. Islow is impervious to anion replacements and can be measured with extracellular Ca2+ as the sole permeant species; Ba can substitute for Ca2+ but Mg2+ cannot. A persistent Ca2+ elevation parallels Islow, when no further internal release takes place. Thus, this slow current could contribute to sustained Ca2+ mobilization and the concomitant regulation of the phototransduction machinery. Although reminiscent of the classical store depletion–operated calcium influx described in other cells, Islow appears to diverge in some significant aspects, such as its large size and insensitivity to SKF96365 and lanthanum; therefore, it may reflect an alternative mechanism for prolonged increase of cytosolic calcium in photoreceptors.

scholarly journals The RhoGAP SPV-1 regulates calcium signaling to control the contractility of theCaenorhabditis elegansspermatheca during embryo transits

2019 ◽  
Vol 30 (7) ◽  
pp. 907-922 ◽  
Author(s):  
Jeff Bouffard ◽  
Alyssa D. Cecchetelli ◽  
Coleman Clifford ◽  
Kriti Sethi ◽  
Ronen Zaidel-Bar ◽  
...  
Keyword(s):  
Calcium Signaling ◽  
Signaling Pathways ◽  
Calcium Release ◽  
Small Gtpases ◽  
Negative Regulator ◽  
Calcium Signal ◽  
Spatial Regulation ◽  
Actomyosin Contractility ◽  
Calcium Indicator ◽  
Rho Family

Contractility of the nonmuscle and smooth muscle cells that comprise biological tubing is regulated by the Rho-ROCK (Rho-associated protein kinase) and calcium signaling pathways. Although many molecular details about these signaling pathways are known, less is known about how they are coordinated spatiotemporally in biological tubes. The spermatheca of the Caenorhabditis elegans reproductive system enables study of the signaling pathways regulating actomyosin contractility in live adult animals. The RhoGAP (GTPase-­activating protein toward Rho family small GTPases) SPV-1 was previously identified as a negative regulator of RHO-1/Rho and spermathecal contractility. Here, we uncover a role for SPV-1 as a key regulator of calcium signaling. spv-1 mutants expressing the calcium indicator GCaMP in the spermatheca exhibit premature calcium release, elevated calcium levels, and disrupted spatial regulation of calcium signaling during spermathecal contraction. Although RHO-1 is required for spermathecal contractility, RHO-1 does not play a significant role in regulating calcium. In contrast, activation of CDC-42 recapitulates many aspects of spv-1 mutant calcium signaling. Depletion of cdc-42 by RNA interference does not suppress the premature or elevated calcium signal seen in spv-1 mutants, suggesting other targets remain to be identified. Our results suggest that SPV-1 works through both the Rho-ROCK and calcium signaling pathways to coordinate cellular contractility.

scholarly journals Norepinephrine-Induced Calcium Signaling and Store-Operated Calcium Entry in Olfactory Bulb Astrocytes

2021 ◽  
Vol 15 ◽  
Author(s):  
Timo Fischer ◽  
Jessica Prey ◽  
Lena Eschholz ◽  
Natalie Rotermund ◽  
Christian Lohr
Keyword(s):  
Olfactory Bulb ◽  
Calcium Signaling ◽  
Calcium Release ◽  
Late Phase ◽  
Brain Slices ◽  
Cytosolic Calcium ◽  
Calcium Entry ◽  
Calcium Transients ◽  
Receptor Subtypes ◽  
Store Operated Calcium Entry

It is well-established that astrocytes respond to norepinephrine with cytosolic calcium rises in various brain areas, such as hippocampus or neocortex. However, less is known about the effect of norepinephrine on olfactory bulb astrocytes. In the present study, we used confocal calcium imaging and immunohistochemistry in mouse brain slices of the olfactory bulb, a brain region with a dense innervation of noradrenergic fibers, to investigate the calcium signaling evoked by norepinephrine in astrocytes. Our results show that application of norepinephrine leads to a cytosolic calcium rise in astrocytes which is independent of neuronal activity and mainly mediated by PLC/IP3-dependent internal calcium release. In addition, store-operated calcium entry (SOCE) contributes to the late phase of the response. Antagonists of both α1- and α2-adrenergic receptors, but not β-receptors, largely reduce the adrenergic calcium response, indicating that both α-receptor subtypes mediate norepinephrine-induced calcium transients in olfactory bulb astrocytes, whereas β-receptors do not contribute to the calcium transients.

Adrenergic Regulation of Calcium Channels in the Heart

2021 ◽  
Vol 84 (1) ◽  
Author(s):  
Arianne Papa ◽  
Jared Kushner ◽  
Steven O. Marx
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Calcium Channels ◽  
Molecular Mechanisms ◽  
Calcium Release ◽  
Calcium Influx ◽  
Electrical Signal ◽  
Annual Review ◽  
Publication Date ◽  
Sympathetic Nervous

Each heartbeat is initiated by the action potential, an electrical signal that depolarizes the plasma membrane and activates a cycle of calcium influx via voltage-gated calcium channels, calcium release via ryanodine receptors, and calcium reuptake and efflux via calcium-ATPase pumps and sodium-calcium exchangers. Agonists of the sympathetic nervous system bind to adrenergic receptors in cardiomyocytes, which, via cascading signal transduction pathways and protein kinase A (PKA), increase the heart rate (chronotropy), the strength of myocardial contraction (inotropy), and the rate of myocardial relaxation (lusitropy). These effects correlate with increased intracellular concentration of calcium, which is required for the augmentation of cardiomyocyte contraction. Despite extensive investigations, the molecular mechanisms underlying sympathetic nervous system regulation of calcium influx in cardiomyocytes have remained elusive over the last 40 years. Recent studies have uncovered the mechanisms underlying this fundamental biologic process, namely that PKA phosphorylates a calcium channel inhibitor, Rad, thereby releasing inhibition and increasing calcium influx. Here, we describe an updated model for how signals from adrenergic agonists are transduced to stimulate calcium influx and contractility in the heart. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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