Regulation of Ca2+-release-activated Ca2+ current (Icrac) by ryanodine receptors in inositol 1,4,5-trisphosphate-receptor-deficient DT40 cells

2001 ◽  
Vol 360 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Kirill KISELYOV ◽  
Dong Min SHIN ◽  
Nikolay SHCHEYNIKOV ◽  
Tomohiro KUROSAKI ◽  
Shmuel MUALLEM

Persistence of capacitative Ca2+ influx in inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)-deficient DT40 cells (DT40IP3R-/−) raises the question of whether gating of Ca2+-release activated Ca2+ current (Icrac) by conformational coupling to Ca2+-release channels is a general mechanism of gating of these channels. In the present work we examined the properties and mechanism of activation of Icrac Ca2+ current in wild-type and DT40IP3R-/− cells. In both cell types passive depletion of internal Ca2+ stores by infusion of EGTA activated a Ca2+ current with similar characteristics and time course. The current was highly Ca2+-selective and showed strong inward rectification, all typical of Icrac. The activator of ryanodine receptor (RyR), cADP-ribose (cADPR), facilitated activation of Icrac, and the inhibitors of the RyRs, 8-N-cADPR, ryanodine and Ruthenium Red, all inhibited Icrac activation in DT40IP3R-/− cells, even after complete depletion of intracellular Ca2+ stores by ionomycin. Wild-type and DT40IP3R-/− cells express RyR isoforms 1 and 3. RyR levels were adapted in DT40IP3R-/− cells to a lower RyR3/RyR1 ratio than in wild-type cells. These results suggest that IP3Rs and RyRs can efficiently gate Icrac in DT40 cells and explain the persistence of Icrac gating by internal stores in the absence of IP3Rs.

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2645-2654 ◽  
Author(s):  
C. Yue ◽  
K.L. White ◽  
W.A. Reed ◽  
T.D. Bunch

Intracellular Ca2+ (Ca2+i) transients during fertilization are critical to the activation of eggs in all species studied. Activation of both the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and ryanodine receptor (RYR) are responsible for the calcium oscillations during fertilization in sea urchin eggs. Using in vitro matured bovine oocytes loaded with Fura-2 AM ester as Ca2+i indicator, we addressed whether IP3Rs and RYRs coexist in mammalian eggs. Our results indicate that microinjection of 50–250 nM IP3 or 10–20 mM caffeine, 100–200 microM ryanodine and 4–8 microM cyclic ADP-ribose all induced Ca2+i release. The Ca2+i release induced by 250 nM IP3 could only be inhibited by prior injection of 1 mg/ml heparin which was overcome by continuous injection of IP3 to 1 microM. Prior injection of either 50 microM ruthenium red, 50 microM procaine or 1 % vehicle medium (VM) did not affect the Ca2+i release induced by IP3. Prior injection of heparin or VM did not affect the Ca2+i release induced by 10–20 mM caffeine or 200 microM ryanodine, but prior injection of 50 microM ruthenium red or procaine completely inhibited the effect of 10–20 mM caffeine. In addition, continuous injection of caffeine up to 40 mM overcame the inhibitory effect of ruthenium red or procaine. The same 50 microM concentration of ruthenium red or procaine only partially blocked the effect of 200 microM ryanodine, but 200 microM ruthenium red or procaine completely blocked the effect of 200 microM ryanodine.(ABSTRACT TRUNCATED AT 250 WORDS)


2003 ◽  
Vol 163 (2) ◽  
pp. 271-282 ◽  
Author(s):  
Julia V. Gerasimenko ◽  
Yoshio Maruyama ◽  
Kojiro Yano ◽  
Nick J. Dolman ◽  
Alexei V. Tepikin ◽  
...  

Ca2+ release from the envelope of isolated pancreatic acinar nuclei could be activated by nicotinic acid adenine dinucleotide phosphate (NAADP) as well as by inositol 1,4,5-trisphosphate (IP3) and cyclic ADP-ribose (cADPR). Each of these agents reduced the Ca2+ concentration inside the nuclear envelope, and this was associated with a transient rise in the nucleoplasmic Ca2+ concentration. NAADP released Ca2+ from the same thapsigargin-sensitive pool as IP3. The NAADP action was specific because, for example, nicotineamide adenine dinucleotide phosphate was ineffective. The Ca2+ release was unaffected by procedures interfering with acidic organelles (bafilomycin, brefeldin, and nigericin). Ryanodine blocked the Ca2+-releasing effects of NAADP, cADPR, and caffeine, but not IP3. Ruthenium red also blocked the NAADP-elicited Ca2+ release. IP3 receptor blockade did not inhibit the Ca2+ release elicited by NAADP or cADPR. The nuclear envelope contains ryanodine and IP3 receptors that can be activated separately and independently; the ryanodine receptors by either NAADP or cADPR, and the IP3 receptors by IP3.


2019 ◽  
Vol 20 (18) ◽  
pp. 4396
Author(s):  
Audrey Der Vartanian ◽  
Julien Chabanais ◽  
Claire Carrion ◽  
Abderrahman Maftah ◽  
Agnès Germot

Past work has shown that the protein O-fucosyltransferase 1 (POFUT1) is involved in mammal myogenic differentiation program. Pofut1 knockdown (Po –) in murine C2C12 cells leads to numerous elongated and thin myotubes, suggesting significant defects in secondary fusion. Among the few pathways involved in this process, NFATc2/IL-4 is described as the major one. To unravel the impact of POFUT1 on secondary fusion, we used wild-type (WT) C2C12 and Po – cell lines to follow Myf6, Nfatc2, Il-4 and Il-4rα expressions during a 120 h myogenic differentiation time course. Secreted IL-4 was quantified by ELISA. IL-4Rα expression and its labeling on myogenic cell types were investigated by Western blot and immunofluorescence, respectively. Phenotypic observations of cells treated with IL-4Rα blocking antibody were performed. In Po –, we found a decrease in nuclei number per myotube and a downexpression of Myf6. The observed downregulation of Nfatc2 is correlated to a diminution of secreted IL-4 and to the low level of IL-4Rα for reserve cells. Neutralization of IL-4Rα on WT C2C12 promotes myonuclear accretion defects, similarly to those identified in Po –. Thus, POFUT1 could be a new controller of myotube growth during myogenesis, especially through NFATc2/IL-4 signaling pathway.


2001 ◽  
Vol 360 (1) ◽  
pp. 17 ◽  
Author(s):  
Kirill KISELYOV ◽  
Dong Min SHIN ◽  
Nikolay SHCHEYNIKOV ◽  
Tomohiro KUROSAKI ◽  
Shmuel MUALLEM

2002 ◽  
Vol 361 (3) ◽  
pp. 605-611 ◽  
Author(s):  
Frank WISSING ◽  
Edmund P. NEROU ◽  
Colin W. TAYLOR

Members of both major families of intracellular Ca2+ channels, ryanodine and inositol 1,4,5-trisphosphate (IP3) receptors, are stimulated by substantial increases in cytosolic free Ca2+ concentration ([Ca2+]c). They thereby mediate Ca2+-induced Ca2+ release (CICR), which allows amplification and regenerative propagation of intracellular Ca2+ signals. In permeabilized hepatocytes, increasing [Ca2+]c to 10μM stimulated release of 30±1% of the intracellular stores within 60s; the EC50 occurred with a free [Ca2+] of 170±29nM. This CICR was abolished at 2°C. The same fraction of the stores was released by CICR before and after depletion of the IP3-sensitive stores, and CICR was not blocked by antagonists of IP3 receptors. Ryanodine, Ruthenium Red and tetracaine affected neither the Ca2+ content of the stores nor the CICR response. Sr2+ and Ba2+ (EC50 = 166nM and 28μM respectively) mimicked the effects of increased [Ca2+] on the intracellular stores, but Ni2+ blocked the passive leak of Ca2+ without blocking CICR. In rapid superfusion experiments, maximal concentrations of IP3 or Ca2+ stimulated Ca2+ release within 80ms. The response to IP3 was complete within 2s, but CICR continued for tens of seconds despite a slow [half-time (t1/2) = 3.54±0.07s] partial inactivation. CICR reversed rapidly (t1/2 = 529±17ms) and completely when the [Ca2+] was reduced. We conclude that hepatocytes express a novel temperature-sensitive, ATP-independent CICR mechanism that is reversibly activated by modest increases in [Ca2+], and does not require IP3 or ryanodine receptors or reversal of the sarcoplasmic/endoplasmic-reticulum Ca2+-ATPase. This mechanism may both regulate the Ca2+ content of the intracellular stores of unstimulated cells and allow even small intracellular Ca2+ signals to be amplified by CICR.


2008 ◽  
Vol 108 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Huafeng Wei ◽  
Ge Liang ◽  
Hui Yang ◽  
Qiujun Wang ◽  
Brian Hawkins ◽  
...  

Background Isoflurane induces cell apoptosis by an unknown mechanism. The authors hypothesized that isoflurane activates inositol 1,4,5-trisphosphate (IP3) receptors on the endoplasmic reticulum (ER) membrane, causing excessive calcium release, triggering apoptosis. Methods The authors determined isoflurane-induced cytotoxicity by measuring caspase-3 activity, lactate dehydrogenase release, MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) reduction, and imaging analysis of cell damage markers (annexin V and propidium iodide staining) in different cell types. The authors used the chicken B lymphocyte with a total knock-out of IP3 receptors, PC12 cells with elevated IP3 receptor activity (transfected with L286V presenilin 1), striatal cells with a knock-in of Q111 Huntingtin, and each cell line's corresponding wild-type controls. The authors also measured the isoflurane-evoked changes of calcium concentration in cytosol and/or mitochondria in these cells. Results Isoflurane induced apoptosis concentration- and time-dependently, and sequentially elevated cytosolic and then mitochondrial calcium in the chicken B-lymphocyte wild-type but not the IP3 receptor total knock-out cells. Thapsigargin, a calcium adenosine triphosphatase inhibitor on ER membranes, induced apoptosis and elevations of calcium in cytosol and mitochondria in both chicken B-lymphocyte wild-type and IP3 receptor total knock-out cells. Isoflurane induced significantly more neurotoxicity and greater calcium release from the ER in L286V PC12 and Q111 Huntingtin striatal cells than in their corresponding wild-type controls, both of which were significantly inhibited by the IP3 receptor antagonist xestospongin C. Conclusion These findings suggest that isoflurane activates the ER membrane IP3 receptor, producing excessive calcium release and triggering apoptosis. Neurons with enhanced IP3 receptor activity, as in certain cases of familial Alzheimer or Huntington disease, may be especially vulnerable to isoflurane cytotoxicity.


Author(s):  
Maryann E. Martone ◽  
Victoria M. Simpliciano ◽  
Ying Zhang ◽  
Thomas J. Deerinck ◽  
Mark H. Ellisman

Components of the endomembrane system in a variety of cell types appear to function in the storage and release of calcium similar to the muscle sarcoplasmic reticulum. Many proteins involved in intracellular calcium regulation in skeletal or smooth muscle, e.g. Ca++ ATPase, calsequestrin, the inositol l,4,5,trisphosphate (TP3) receptor and the ryanodine binding protein, are found in the nervous system where they are particularly abundant within the smooth endoplasmic reticulum (SER) of cerebellar Purkinje neurons. Immunolocalization studies suggest, however, that calcium regulatory proteins are not uniformly distributed within the SER but are concentrated in or excluded from certain domains. For example, the IP3 and ryanodine receptors, two distinct calcium channels which mediate calcium release by different ligands, are found associated with the SER in cell bodies and dendrites of chick cerebellum but only the IP3 receptor is found within dendritic spines. These results are consistent with evidence that cells may possess multiple intracellular calcium stores that are pharmacologically, spatially and perhaps physically distinct.


1994 ◽  
Vol 266 (5) ◽  
pp. C1421-C1431 ◽  
Author(s):  
J. F. Kuemmerle ◽  
K. S. Murthy ◽  
G. M. Makhlouf

We have previously shown that Ca2+ mobilization in longitudinal muscle is not mediated by inositol 1,4,5-trisphosphate (IP3) and depends on an obligatory influx of Ca2+. The present study examined whether Ca2+ influx activates ryanodine-sensitive Ca2+ channels to cause Ca(2+)-induced Ca2+ release. Ryanodine bound with high affinity to longitudinal muscle cells [dissociation constant (Kd) 7.3 +/- 0.3 nM] and microsomes (Kd 7.5 +/- 0.4 nM) and induced concentration-dependent 45Ca2+ efflux [50% effective concentration (EC50) 1.3 +/- 0.5 nM], increase in cytosolic free Ca2+ (EC50 2.0 +/- 0.7 nM), and contraction (EC50 0.9 +/- 0.2 nM) but had no effect in circular muscle cells. Ryanodine binding and ryanodine-induced Ca2+ release were enhanced by caffeine and inhibited by dantrolene and ruthenium red but were not affected by IP3 or heparin. Changes in Ca2+ concentration (50-500 nM) caused Ca2+ release from permeabilized longitudinal but not circular muscle cells loaded with 45Ca2+. The contractile agonist cholecystokinin-8 elicited 45Ca2+ efflux in both circular and longitudinal muscle cells; efflux in longitudinal muscle cells was abolished by Ca2+ channel blockers and by pretreatment of the cells with ryanodine. Pretreatment with thapsigargin abolished agonist-induced 45Ca2+ efflux in both cell types. We conclude that ryanodine-sensitive IP3-insensitive Ca2+ release channels with properties similar to those in cardiac muscle are present in longitudinal but not circular muscle cells of intestine and that agonist-mediated Ca2+ influx activates these channels, leading to Ca(2+)-induced Ca2+ release.


1995 ◽  
Vol 6 (8) ◽  
pp. 945-951 ◽  
Author(s):  
J Keizer ◽  
Y X Li ◽  
S Stojilković ◽  
J Rinzel

Oscillations in intracellular Ca2+ can be induced by a variety of cellular signalling processes (Woods et al., 1986; Berridge 1988; Jacob et al., 1988) and appear to play a role in secretion (Stojilković et al., 1994), fertilization (Miyazaki et al., 1993), and smooth muscle contraction (Iino and Tsukioka, 1994). Recently, great progress has been made in understanding the mechanisms involved in a particular class of Ca2+ oscillation, associated with the second messenger inositol 1,4,5-trisphosphate (InsP3) (Berridge, 1993). Working in concert with intracellular Ca2+, InsP3 controls Ca2+ release via the InsP3 receptor in the endoplasmic reticulum (ER) (Berridge and Irvine, 1989). The IP3 receptor is regulated by its coagonists InsP3 and Ca2+, which both activate and inhibit Ca2+ release (Finch et al., 1991; Bezprozvanny et al., 1991; De Young and Keizer, 1992). These processes, together with the periodic activation of Ca2+ uptake into the ER, have been identified as key features in the mechanism of InsP3-induced Ca2+ oscillations in pituitary gonadotrophs (Li et al., 1994), Xenopus laevis oocytes (Lechleiter and Clapham, 1992; Atri et al., 1993), and other cell types (Keizer and De Young, 1993). Earlier discussions and models of InsP3-induced Ca2+ oscillations focused on the nature and number of internal releasable pools of Ca2+ (Goldbeter et al., 1990; Swillens and Mercan, 1990; Somogyi and Stucki, 1991), the importance of oscillations in InsP3 (Meyer and Stryer, 1988), and other issues not based on detailed experimental findings in specific cells types.


1997 ◽  
Vol 272 (4) ◽  
pp. L659-L664 ◽  
Author(s):  
M. S. Kannan ◽  
Y. S. Prakash ◽  
T. Brenner ◽  
J. R. Mickelson ◽  
G. C. Sieck

Acetylcholine (ACh) induces repetitive, propagating intracellular Ca2+ concentration ([Ca2+]i) oscillations in porcine tracheal smooth muscle (TSM) cells. Using real-time confocal microscopy, we examined the role of sarcoplasmic reticulum (SR) Ca2+ release through inositol 1,4,5-trisphosphate (IP3) receptor and ryanodine receptor (RyR) channels in ACh-induced [Ca2+]i oscillations. In beta-escin permeabilized TSM cells, exposure to ACh in the presence of GTP also resulted in [Ca2+]i oscillations. [Ca2+]i oscillations could not be initiated by IP3 alone; however, an elevation of [Ca2+]i was observed. During ongoing [Ca2+]i oscillations, exposure to heparin, an IP3 receptor antagonist, caused a slowing of oscillation frequency but not complete inhibition. In contrast, ruthenium red, a RyR antagonist, completely abolished ACh-induced [Ca2+]i oscillations. Reverse transcriptase-polymerase chain reaction of TSM mRNA demonstrated the expression of RyR-2 and RyR-3 isoforms of the RyR. These results indicate that SR Ca2+ release through RyR channels is critical for ACh-induced [Ca2+]i oscillations in porcine TSM cells.


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