共查询到20条相似文献,搜索用时 15 毫秒
1.
Sean R. Cleary Xuan Fang Ellen E. Cho Marsha P. Pribadi Jaroslava Seflova Jordan R. Beach Peter M. Kekenes-Huskey Seth L. Robia 《The Journal of biological chemistry》2022,298(7)
The ATP-dependent ion pump sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) sequesters Ca2+ in the endoplasmic reticulum to establish a reservoir for cell signaling. Because of its central importance in physiology, the activity of this transporter is tightly controlled via direct interactions with tissue-specific regulatory micropeptides that tune SERCA function to match changing physiological conditions. In the heart, the micropeptide phospholamban (PLB) inhibits SERCA, while dwarf open reading frame (DWORF) stimulates SERCA. These competing interactions determine cardiac performance by modulating the amplitude of Ca2+ signals that drive the contraction/relaxation cycle. We hypothesized that the functions of these peptides may relate to their reciprocal preferences for SERCA binding; SERCA binds PLB more avidly at low cytoplasmic [Ca2+] but binds DWORF better when [Ca2+] is high. In the present study, we demonstrated this opposing Ca2+ sensitivity is due to preferential binding of DWORF and PLB to different intermediate states that SERCA samples during the Ca2+ transport cycle. We show PLB binds best to the SERCA E1-ATP state, which prevails at low [Ca2+]. In contrast, DWORF binds most avidly to E1P and E2P states that are more populated when Ca2+ is elevated. Moreover, FRET microscopy revealed dynamic shifts in SERCA–micropeptide binding equilibria during cellular Ca2+ elevations. A computational model showed that DWORF exaggerates changes in PLB–SERCA binding during the cardiac cycle. These results suggest a mechanistic basis for inhibitory versus stimulatory micropeptide function, as well as a new role for DWORF as a modulator of dynamic oscillations of PLB–SERCA regulatory interactions. 相似文献
2.
Kenichi Ikeda Toshiaki Nakajima Yumiko Yamamoto Nami Takano Tomofumi Tanaka Hironobu Kikuchi Gaku Oguri Toshihiro Morita Fumitaka Nakamura Issei Komuro 《Cell calcium》2013
Expression of transient receptor potential canonical channels (TRPC) and the effects of transforming growth factor-β1 (TGF-β1) on Ca2+ signals and fibroblast proliferation were investigated in human cardiac fibroblasts. The conventional and quantitative real-time RT-PCR, western blot, immunocytochemical analysis, and intracellular Ca2+ concentration [Ca2+]i measurement were applied. Cell proliferation and cell cycle progression were assessed using MTT assays and fluorescence activated cell sorting. Human cardiac fibroblasts have the expression of TRPC1,3,4,6 mRNA and proteins. 1-oleoyl-2-acetyl-sn-glycerol (OAG) and thapsigargin induced extracellular Ca2+-mediated [Ca2+]i rise. siRNA for knock down of TRPC6 reduced OAG-induced Ca2+ entry. Hyperforin as well as angiotensin II (Ang II) induced Ca2+ entry. KB-R7943, a reverse-mode Na+/Ca2+ exchanger (NCX) inhibitor, and/or replacement of Na+ with NMDG+ inhibited thapsigargin-, OAG- and Ang II-induced Ca2+ entry. Treatment with TGF-β1 increased thapsigargin-, OAG- and Ang II-induced Ca2+ entry with an enhancement of TRPC1,6 protein expression, suppressed by KB-R7943. TGF-β1 and AngII promoted cell cycle progression from G0/G1 to S/G2/M and cell proliferation. A decrease of the extracellular Ca2+ and KB-R7943 suppressed it. Human cardiac fibroblasts contain several TRPC-mediated Ca2+ influx pathways, which activate the reverse-mode NCX. TGF-β1 enhances the Ca2+ influx pathways requiring Ca2+ signals for its effect on fibroblast proliferation. 相似文献
3.
Miryam Andrea Hortua Triana Karla M. Márquez-Nogueras Stephen A. Vella Silvia N.J. Moreno 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(11):1846-1856
Toxoplasma gondii has a complex life cycle involving different hosts and is dependent on fast responses, as the parasite reacts to changing environmental conditions. T. gondii causes disease by lysing the host cells that it infects and it does this by reiterating its lytic cycle, which consists of host cell invasion, replication inside the host cell, and egress causing host cell lysis. Calcium ion (Ca2+) signaling triggers activation of molecules involved in the stimulation and enhancement of each step of the parasite lytic cycle. Ca2+ signaling is essential for the cellular and developmental changes that support T. gondii parasitism.The characterization of the molecular players and pathways directly activated by Ca2+ signaling in Toxoplasma is sketchy and incomplete. The evolutionary distance between Toxoplasma and other eukaryotic model systems makes the comparison sometimes not informative. The advent of new genomic information and new genetic tools applicable for studying Toxoplasma biology is rapidly changing this scenario. The Toxoplasma genome reveals the presence of many genes potentially involved in Ca2+ signaling, even though the role of most of them is not known. The use of Genetically Encoded Calcium Indicators (GECIs) has allowed studies on the role of novel calcium-related proteins on egress, an essential step for the virulence and dissemination of Toxoplasma. In addition, the discovery of new Ca2+ players is generating novel targets for drugs, vaccines, and diagnostic tools and a better understanding of the biology of these parasites. 相似文献
4.
Carly A. Buckner Alison L. Buckner Stan A. Koren Michael A. Persinger Robert M. Lafrenie 《PloS one》2015,10(4)
Electromagnetic field (EMF) exposures affect many biological systems. The reproducibility of these effects is related to the intensity, duration, frequency, and pattern of the EMF. We have shown that exposure to a specific time-varying EMF can inhibit the growth of malignant cells. Thomas-EMF is a low-intensity, frequency-modulated (25-6 Hz) EMF pattern. Daily, 1 h, exposures to Thomas-EMF inhibited the growth of malignant cell lines including B16-BL6, MDA-MB-231, MCF-7, and HeLa cells but did not affect the growth of non-malignant cells. Thomas-EMF also inhibited B16-BL6 cell proliferation in vivo. B16-BL6 cells implanted in syngeneic C57b mice and exposed daily to Thomas-EMF produced smaller tumours than in sham-treated controls. In vitro studies showed that exposure of malignant cells to Thomas-EMF for > 15 min promoted Ca2+ influx which could be blocked by inhibitors of voltage-gated T-type Ca2+ channels. Blocking Ca2+ uptake also blocked Thomas-EMF-dependent inhibition of cell proliferation. Exposure to Thomas-EMF delayed cell cycle progression and altered cyclin expression consistent with the decrease in cell proliferation. Non-malignant cells did not show any EMF-dependent changes in Ca2+ influx or cell growth. These data confirm that exposure to a specific EMF pattern can affect cellular processes and that exposure to Thomas-EMF may provide a potential anti-cancer therapy. 相似文献
5.
Nóra M. Márkus Philip Hasel Jing Qiu Karen F. S. Bell Samuel Heron Peter C. Kind Owen Dando T. Ian Simpson Giles E. Hardingham 《PloS one》2016,11(2)
Uptake of Ca2+ into the mitochondrial matrix controls cellular metabolism and survival-death pathways. Several genes are implicated in controlling mitochondrial Ca2+ uptake (mitochondrial calcium regulatory genes, MCRGs), however, less is known about the factors which influence their expression level. Here we have compared MCRG mRNA expression, in neural cells of differing type (cortical neurons vs. astrocytes), differing neuronal subtype (CA3 vs. CA1 hippocampus) and in response to Ca2+ influx, using a combination of qPCR and RNA-seq analysis. Of note, we find that the Mcu-regulating Micu gene family profile differs substantially between neurons and astrocytes, while expression of Mcu itself is markedly different between CA3 and CA1 regions in the adult hippocampus. Moreover, dynamic control of MCRG mRNA expression in response to membrane depolarization-induced Ca2+ influx is also apparent, resulting in repression of Letm1, as well as Mcu. Thus, the mRNA expression profile of MCRGs is not fixed, which may cause differences in the coupling between cytoplasmic and mitochondrial Ca2+, as well as diversity of mitochondrial Ca2+ uptake mechanisms. 相似文献
6.
Ca2+ regulates cell differentiation and morphogenesis in a diversity of organisms and dysregulation of Ca2+ signal transduction pathways leads to many cellular pathologies. In Dictyostelium Ca2+ induces ecmB expression and stalk cell differentiation in vitro. Here we have analyzed the pattern of ecmB expression in intact and bisected slugs and the effect of agents that affect Ca2+ levels or antagonize calmodulin (CaM) on this expression pattern. We have shown that Ca2+ and CaM regulate ecmB expression and pstAB/pstB cell differentiation in vivo. Agents that increase intracellular Ca2+ levels increased ecmB expression and/or pstAB and pstB cell differentiation, while agents that decrease intracellular Ca2+ or antagonize CaM decreased it. In isolated slug tips agents that affect Ca2+ levels and antagonize CaM had differential effect on ecmB expression and cell differentiation in the anterior versus posterior zones. Agents that increase intracellular Ca2+ levels increased the number of ecmB expressing cells in the anterior region of slugs, while agents that decrease intracellular Ca2+ levels or antagonize CaM activity increased the number of ecmB expressing cells in the posterior. We have also demonstrated that agents that affect Ca2+ levels or antagonize CaM affect cells motility and regeneration of shape in isolated slug tips and backs and regeneration of tips in isolated slug backs. To our knowledge, this is the first study detailing the pattern of ecmB expression in regenerating slugs as well as the role of Ca2+ and CaM in the regeneration process and ecmB expression. 相似文献
7.
Yongping Gao Christopher M. Gillen Michele G. Wheatly 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2009,152(3):216-225
Calmodulin (CaM) is a highly conserved calcium (Ca2+) binding protein that transduces Ca2+ signals into downstream effects influencing a range of cellular processes, including Ca2+ homeostasis. The present study explores CaM expression when Ca2+ homeostasis is challenged during the mineralization cycle of the freshwater crayfish (Procambarus clarkii). In this paper we report the cloning of a CaM gene from axial abdominal crayfish muscle (referred to as pcCaM). The pcCaM mRNA is ubiquitously expressed but is far more abundant in excitable tissue (muscle, nerve) than in any epithelia (gill, antennal gland, digestive) suggesting that it plays a greater role in the biology of excitation than in epithelial ion transport. In muscle cells the pcCaM was colocalized on the plasma membrane with the Ca2+ ATPase (PMCA) known to regulate intracellular Ca2+ through basolateral efflux. While PMCA exhibits a greater upregulation in epithelia (than in non-epithelial tissues) during molting stages requiring transcellular Ca2+ flux (pre- and postmolt compared with intermolt), expression of pcCaM exhibited a uniform increase in epithelial and non-epithelial tissues alike. The common increase in expression of CaM in all tissues during pre- and postmolt stages (compared with intermolt) suggests that the upregulation is systemically (hormonally) mediated. Colocalization of CaM with PMCA confirms physiological findings that their regulation is linked. 相似文献
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《Cell calcium》2014,55(5):238-251
Cardiogenesis depends on a tightly regulated balance between proliferation and differentiation of cardiac progenitor cells (CPCs) and their cardiomyocyte descendants. While exposure of early mouse embryos to Ca2+ channel antagonists has been associated with abnormal cardiac morphogenesis, less is known about the consequences of Ca2+ channel blockade on proliferation and differentiation of CPCs at the cellular level. Here we showed that at embryonic day (E) 11.5, the murine ventricles express several L-type and T-type Ca2+ channel isoforms, and that the dihydropyridine Ca2+ channel antagonist, nifedipine, blunts isoproterenol induced increases in intracellular Ca2+. Nifedipine mediated Ca2+ channel blockade was associated with a reduction in cell cycle activity of E11.5 CPCs and impaired assembly of the cardiomyocyte contractile apparatus. Furthermore, in cell transplantation experiments, systemic administration of nifedipine to adult mice receiving transplanted E11.5 ventricular cells (containing CPCs and cardiomyocytes) was associated with smaller graft sizes compared to vehicle treated control animals. These data suggest that intracellular Ca2+ is a critical regulator of the balance between CPC proliferation and differentiation and demonstrate that interactions between pharmacological drugs and transplanted cells could have a significant impact on the effectiveness of cell based therapies for myocardial repair. 相似文献
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Daphne Atlas 《Cellular signalling》2010,22(11):1597-1603
Voltage-gated calcium channels (VGCC) are involved in a large variety of cellular Ca2+ signaling processes, including exocytosis, a Ca2+ dependent release of neurotransmitters and hormones.Great progress has been made in understanding the mode of action of VGCC in exocytosis, a process distinguished by two sequential yet independent Ca2+ binding reactions. First, Ca2+ binds at the selectivity filter, the EEEE motif of the VGCC, and second, subsequent to a brief and intense Ca2+ inflow to synaptotagmin, a vesicular protein. Inquiry into the functional and physical interactions of the channels with synaptic proteins has demonstrated that exocytosis is triggered during the initial Ca2+ binding at the channel pore, prior to Ca2+ entry. Accordingly, a cycle of secretion begins by an incoming stimulus that releases vesicles from a releasable pool upon Ca2+ binding at the pore, and at the same time, the transient increase in [Ca2+]i primes a fresh set of non-releasable vesicles, to be fused by the next incoming stimulus.We propose a model, in which the Ca2+ binding at the EEEE motif and the consequent conformational changes in the channel are the primary event in triggering secretion, while synaptotagmin acts as a vesicle docking protein. Thus, the channel serves as the molecular On/Off signaling switch, where the predominance of a conformational change in Ca2+-bound channel provides for the fast secretory process. 相似文献
13.
Mathieu Brochet Mark O. Collins Terry K. Smith Eloise Thompson Sarah Sebastian Katrin Volkmann Frank Schwach Lia Chappell Ana Rita Gomes Matthew Berriman Julian C. Rayner David A. Baker Jyoti Choudhary Oliver Billker 《PLoS biology》2014,12(3)
Many critical events in the Plasmodium life cycle rely on the controlled release of Ca2+ from intracellular stores to activate stage-specific Ca2+-dependent protein kinases. Using the motility of Plasmodium berghei ookinetes as a signalling paradigm, we show that the cyclic guanosine monophosphate (cGMP)-dependent protein kinase, PKG, maintains the elevated level of cytosolic Ca2+ required for gliding motility. We find that the same PKG-dependent pathway operates upstream of the Ca2+ signals that mediate activation of P. berghei gametocytes in the mosquito and egress of Plasmodium falciparum merozoites from infected human erythrocytes. Perturbations of PKG signalling in gliding ookinetes have a marked impact on the phosphoproteome, with a significant enrichment of in vivo regulated sites in multiple pathways including vesicular trafficking and phosphoinositide metabolism. A global analysis of cellular phospholipids demonstrates that in gliding ookinetes PKG controls phosphoinositide biosynthesis, possibly through the subcellular localisation or activity of lipid kinases. Similarly, phosphoinositide metabolism links PKG to egress of P. falciparum merozoites, where inhibition of PKG blocks hydrolysis of phosphatidylinostitol (4,5)-bisphosphate. In the face of an increasing complexity of signalling through multiple Ca2+ effectors, PKG emerges as a unifying factor to control multiple cellular Ca2+ signals essential for malaria parasite development and transmission. 相似文献
14.
Christopher J. Derrick Anna H. York-Andersen Timothy T. Weil 《Journal of visualized experiments : JoVE》2016,(114)
Egg activation is a universal process that includes a series of events to allow the fertilized egg to complete meiosis and initiate embryonic development. One aspect of egg activation, conserved across all organisms examined, is a change in the intracellular concentration of calcium (Ca2+) often termed a ''Ca2+ wave''. While the speed and number of oscillations of the Ca2+ wave varies between species, the change in intracellular Ca2+ is key in bringing about essential events for embryonic development. These changes include resumption of the cell cycle, mRNA regulation, cortical granule exocytosis, and rearrangement of the cytoskeleton.In the mature Drosophila egg, activation occurs in the female oviduct prior to fertilization, initiating a series of Ca2+-dependent events. Here we present a protocol for imaging the Ca2+ wave in Drosophila. This approach provides a manipulable model system to interrogate the mechanism of the Ca2+ wave and the downstream changes associated with it. 相似文献
15.
《Cell calcium》2018
Cytosolic Ca2+ concentration levels fluctuate in an ordered manner along the cell cycle, in line with the fact that Ca2+ is involved in the regulation of cell proliferation. Cell proliferation should be an error-free process, yet is endangered by mistakes. In fact, a complex network of proteins ensures that cell cycle does not progress until the previous phase has been successfully completed. Occasionally, errors occur during the cell cycle leading to cell cycle arrest. If the error is severe, and the cell cycle checkpoints work perfectly, this results into cellular demise by activation of apoptotic or non-apoptotic cell death programs. Cancer is characterized by deregulated proliferation and resistance against cell death. Ca2+ is a central key to these phenomena as it modulates signaling pathways that control oncogenesis and cancer progression. Here, we discuss how Ca2+ participates in the exogenous and endogenous signals controlling cell proliferation, as well as in the mechanisms by which cells die if irreparable cell cycle damage occurs. Moreover, we summarize how Ca2+ homeostasis remodeling observed in cancer cells contributes to deregulated cell proliferation and resistance to cell death. Finally, we discuss the possibility to target specific components of Ca2+ signal pathways to obtain cytostatic or cytotoxic effects. 相似文献
16.
Polar Calcium Flux in Sunflower Hypocotyl Segments : II. The Effect of Segment Orientation, Growth, and Respiration 总被引:1,自引:1,他引:0
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Calcium flux in sunflower (Helianthus annuus L. cv Russian mammoth) hypocotyl was measured with a Ca2+ electrode as the increase or decrease in Ca2+ in an aqueous solution (10 micromolar CaCl2) in contact with either the basal or apical end of 20 millimeter segments. Ca2+ efflux was significantly higher at the apical end compared with the basal end; this apparent polarity was maintained even when the segments were inverted. No significant difference was observed in the cation exchange capacity of apical and basal cell walls that could explain the difference in Ca2+ efflux at opposite ends of the hypocotyl segment. The presence of exogenous indoleacetic acid (IAA) in the segment medium resulted in the promotion of both Ca2+ efflux and segment elongation. However, osmotic inhibition of the IAA-induced elongation did not result in inhibiting the IAA-induced Ca2+ efflux. Ca2+ efflux was inhibited by cyanide. Lowering the temperature from 25°C also caused the gradual reduction of Ca2+ efflux; at 5°C the hypocotyl segments showed a net absorption of Ca2+ from the segment medium. These findings support the suggestion that: (a) the observed Ca2+ efflux in hypocotyl segments is probably the manifestation of the system which maintains the transmembrane Ca2+ gradient at the cellular level. (b) The acropetal polarity of Ca2+ efflux may be the result of the involvement of Ca2+ in the basipetal transport of IAA. 相似文献
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M Saito 《Experimental cell research》1979,123(1):79-86
Effect of extracellular Ca2+ on the morphogenesis of the cellular slime mold Dictyostelium discoideum was examined on agar plate. The concentration of Ca2+ in agar plate was controlled by keeping the concentration of a chelating reagent EGTA constant and varying the concentration of total calcium. From experiments in which EGTA concentration was kept at 2.0 × 10?3 M, it was found that by decreasing Ca2+ concentration the morphogenesis was modified so that development of the aggregating amebae into fruiting bodies was accelerated and the period of migrating slugs was shortened. Below 1.0 × 10?3 M of Ca2+ concentration, the total number of aggregates initially increased with decreasing Ca2+ concentration, reached a maximum at about 3.0 × 10?7 M of Ca2+ concentration and hereafter decreased with decreasing Ca2+ concentration. The number of mature fruiting bodies obtained at 36 h period after starvation depends on Ca2+ concentration and the total number of aggregates. The cell aggregation initiated at the same time period after starvation even at an extreme case of 1.0 × 10?8 M of Ca2+ concentration as under enough Ca2+ supply, while the formation of mature fruiting body was seriously inhibited. These observation suggested that the cAMP-mediated cell aggregation in D. discoideum is a Ca2+-independent phenomena, although extracellular Ca2+ is necessary for the normal development of the aggregated amebae. 相似文献
19.
Zhe Xu Leah Lefevre Tom Ducibella Richard M. Schultz Gregory S. Kopf 《Developmental biology》1996,180(2):594
Results of numerous experiments indicate that the transient rise in intracellular Ca2+following sperm–egg fusion is essential for the subsequent events that constitute egg activation. Some events of egg activation, e.g., cortical granule exocytosis, however, appear more sensitive to intracellular Ca2+than other events, e.g., cell cycle resumption. To examine if specific events of egg activation have different thresholds for Ca2+, we manipulated buffered intracellular Ca2+concentrations by microinjecting Ca2+-BAPTA buffers and then examined the effect on the cortical granule exocytosis, recruitment of maternal mRNAs, and cell cycle resumption. We find that whereas cortical granule exocytosis occurs over a narrow threshold range of injected free Ca2+concentrations between 0.5 and 1.0 μM,recruitment of maternal mRNAs is only partially stimulated at injected free Ca2+concentrations of 2.5 μM,and no evidence for cell cycle resumption was observed (up to 2.5 μMCa2+). Although the Ca2+- and phospholipid-dependent protein kinase, protein kinase C, is implicated in aspects of egg activation, calmodulin is also a potential target for the transient increase in Ca2+that occurs following fertilization. Whereas incubation of eggs in the presence of the calmodulin antagonist W-7 followed by insemination does not block cortical granule exocytosis, cell cycle resumption, as assessed by the metaphase-to-anaphase transition, a decrease in histone H1 kinase activity and the time course for the emission of the second polar body are significantly delayed/inhibited. 相似文献
20.
Yaping Lin-Moshier Peter J. Sebastian LeeAnn Higgins Natalie D. Sampson Jane E. Hewitt Jonathan S. Marchant 《The Journal of biological chemistry》2013,288(1):355-367
Changes in cytoplasmic Ca2+ concentration, resulting from activation of intracellular Ca2+ channels within the endoplasmic reticulum, regulate several aspects of cellular growth and differentiation. Ca2+ homeostasis endoplasmic reticulum protein (CHERP) is a ubiquitously expressed protein that has been proposed as a regulator of both major families of endoplasmic reticulum Ca2+ channels, inositol 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs), with resulting effects on mitotic cycling. However, the manner by which CHERP regulates intracellular Ca2+ channels to impact cellular growth is unknown. Here, we challenge previous findings that CHERP acts as a direct cytoplasmic regulator of IP3Rs and RyRs and propose that CHERP acts in the nucleus to impact cellular proliferation by regulating the function of the U2 snRNA spliceosomal complex. The previously reported effects of CHERP on cellular growth therefore are likely indirect effects of altered spliceosomal function, consistent with prior data showing that loss of function of U2 snRNP components can interfere with cell growth and induce cell cycle arrest. 相似文献