scholarly journals Relocalization of STIM1 in mouse oocytes at fertilization: early involvement of store-operated calcium entry

Reproduction ◽  
2009 ◽  
Vol 138 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Carolina Gómez-Fernández ◽  
Eulalia Pozo-Guisado ◽  
Miguel Gañán-Parra ◽  
Mario J Perianes ◽  
Ignacio S Álvarez ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Calcium Waves ◽  
Resting Cells ◽  
Metaphase Arrest ◽  
Mouse Oocytes ◽  
Store Depletion ◽  
Store Operated Calcium Entry ◽  
Mature Mouse

Calcium waves represent one of the most important intracellular signaling events in oocytes at fertilization required for the exit from metaphase arrest and the resumption of the cell cycle. The molecular mechanism ruling this signaling has been described in terms of the contribution of intracellular calcium stores to calcium spikes. In this work, we considered the possible contribution of store-operated calcium entry (SOCE) to this signaling, by studying the localization of the protein STIM1 in oocytes. STIM1 has been suggested to play a key role in the recruitment and activation of plasma membrane calcium channels, and we show here that mature mouse oocytes express this protein distributed in discrete clusters throughout their periphery in resting cells, colocalizing with the endoplasmic reticulum marker calreticulin. However, immunolocalization of the endogenous STIM1 showed considerable redistribution over larger areas or patches covering the entire periphery of the oocyte during Ca2+ store depletion induced with thapsigargin or ionomycin. Furthermore, pharmacological activation of endogenous phospholipase C induced a similar pattern of redistribution of STIM1 in the oocyte. Finally, fertilization of mouse oocytes revealed a significant and rapid relocalization of STIM1, similar to that found after pharmacological Ca2+ store depletion. This particular relocalization supports a role for STIM1 and SOCE in the calcium signaling during early stages of fertilization.

Store-operated calcium entry and increased endothelial cell permeability

2000 ◽  
Vol 279 (5) ◽  
pp. L815-L824 ◽  
Author(s):  
Natalie Norwood ◽  
Timothy M. Moore ◽  
David A. Dean ◽  
Rakesh Bhattacharjee ◽  
Ming Li ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Calcium Current ◽  
Calcium Release ◽  
Calcium Entry ◽  
Extracellular Calcium ◽  
Cell Permeability ◽  
Calcium Stores ◽  
Store Depletion ◽  
Endothelial Cell Permeability ◽  
Store Operated Calcium Entry

We hypothesized that myosin light chain kinase (MLCK) links calcium release to activation of store-operated calcium entry, which is important for control of the endothelial cell barrier. Acute inhibition of MLCK caused calcium release from inositol trisphosphate-sensitive calcium stores and prevented subsequent activation of store-operated calcium entry by thapsigargin, suggesting that MLCK serves as an important mechanism linking store depletion to activation of membrane calcium channels. Moreover, in voltage-clamped single rat pulmonary artery endothelial cells, thapsigargin activated an inward calcium current that was abolished by MLCK inhibition. F-actin disruption activated a calcium current, and F-actin stabilization eliminated the thapsigargin-induced current. Thapsigargin increased endothelial cell permeability in the presence, but not in the absence, of extracellular calcium, indicating the importance of calcium entry in decreasing barrier function. Although MLCK inhibition prevented thapsigargin from stimulating calcium entry, it did not prevent thapsigargin from increasing permeability. Rather, inhibition of MLCK activity increased permeability that was especially prominent in low extracellular calcium. In conclusion, MLCK links store depletion to activation of a store-operated calcium entry channel. However, inhibition of calcium entry by MLCK is not sufficient to prevent thapsigargin from increasing endothelial cell permeability.

scholarly journals Calcium Sensors STIM1 and STIM2 Regulate Different Calcium Functions in Cultured Hippocampal Neurons

2021 ◽  
Vol 12 ◽  
Author(s):  
Liliya Kushnireva ◽  
Eduard Korkotian ◽  
Menahem Segal
Keyword(s):  
Dendritic Spines ◽  
Hippocampal Neurons ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Plastic Properties ◽  
Calcium Sensors ◽  
Central Neurons ◽  
Transient Rise ◽  
Store Operated Calcium Entry ◽  
Adult Neuron

There are growing indications for the involvement of calcium stores in the plastic properties of neurons and particularly in dendritic spines of central neurons. The store-operated calcium entry (SOCE) channels are assumed to be activated by the calcium sensor stromal interaction molecule (STIM)which leads to activation of its associated Orai channel. There are two STIM species, and the differential role of the two in SOCE is not entirely clear. In the present study, we were able to distinguish between transfected STIM1, which is more mobile primarily in young neurons, and STIM2 which is less mobile and more prominent in older neurons in culture. STIM1 mobility is associated with spontaneous calcium sparks, local transient rise in cytosolic [Ca2+]i, and in the formation and elongation of dendritic filopodia/spines. In contrast, STIM2 is associated with older neurons, where it is mobile and moves into dendritic spines primarily when cytosolic [Ca2+]i levels are reduced, apparently to activate resident Orai channels. These results highlight a role for STIM1 in the regulation of [Ca2+]i fluctuations associated with the formation of dendritic spines or filopodia in the developing neuron, whereas STIM2 is associated with the maintenance of calcium entry into stores in the adult neuron.

scholarly journals The tethering function of mitofusin2 controls osteoclast differentiation by modulating the Ca2+–NFATc1 axis

2020 ◽  
Vol 295 (19) ◽  
pp. 6629-6640 ◽  
Author(s):  
Anna Ballard ◽  
Rong Zeng ◽  
Allahdad Zarei ◽  
Christine Shao ◽  
Linda Cox ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bone Mass ◽  
Intracellular Signaling ◽  
Osteoclast Differentiation ◽  
Calcium Entry ◽  
Calcium Handling ◽  
Mitochondrial Network ◽  
Female Mice ◽  
Mitochondrial Functions ◽  
Store Operated Calcium Entry

Dynamic regulation of the mitochondrial network by mitofusins (MFNs) modulates energy production, cell survival, and many intracellular signaling events, including calcium handling. However, the relative importance of specific mitochondrial functions and their dependence on MFNs vary greatly among cell types. Osteoclasts have many mitochondria, and increased mitochondrial biogenesis and oxidative phosphorylation enhance bone resorption, but little is known about the mitochondrial network or MFNs in osteoclasts. Because expression of each MFN isoform increases with osteoclastogenesis, we conditionally deleted MFN1 and MFN2 (double conditional KO (dcKO)) in murine osteoclast precursors, finding that this increased bone mass in young female mice and abolished osteoclast precursor differentiation into mature osteoclasts in vitro. Defective osteoclastogenesis was reversed by overexpression of MFN2 but not MFN1; therefore, we generated mice lacking only MFN2 in osteoclasts. MFN2-deficient female mice had increased bone mass at 1 year and resistance to Receptor Activator of NF-κB Ligand (RANKL)-induced osteolysis at 8 weeks. To explore whether MFN-mediated tethering or mitophagy is important for osteoclastogenesis, we overexpressed MFN2 variants defective in either function in dcKO precursors and found that, although mitophagy was dispensable for differentiation, tethering was required. Because the master osteoclastogenic transcriptional regulator nuclear factor of activated T cells 1 (NFATc1) is calcium-regulated, we assessed calcium release from the endoplasmic reticulum and store-operated calcium entry and found that the latter was blunted in dcKO cells. Restored osteoclast differentiation by expression of intact MFN2 or the mitophagy-defective variant was associated with normalization of store-operated calcium entry and NFATc1 levels, indicating that MFN2 controls mitochondrion–endoplasmic reticulum tethering in osteoclasts.

scholarly journals Dexamethasone stimulates store-operated calcium entry and protein degradation in cultured L6 myotubes through a phospholipase A2-dependent mechanism

2010 ◽  
Vol 298 (5) ◽  
pp. C1127-C1139 ◽  
Author(s):  
Kiyoshi Itagaki ◽  
Michael Menconi ◽  
Bozena Antoniu ◽  
Qin Zhang ◽  
Patricia Gonnella ◽  
...  
Keyword(s):  
Calcium Channel ◽  
Protein Degradation ◽  
Intracellular Calcium ◽  
Muscle Wasting ◽  
Muscle Protein ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Fluorescence Measurements ◽  
Store Operated Calcium Entry

Muscle wasting in various catabolic conditions is at least in part regulated by glucocorticoids. Increased calcium levels have been reported in atrophying muscle. Mechanisms regulating calcium homeostasis in muscle wasting, in particular the role of glucocorticoids, are poorly understood. Here we tested the hypothesis that glucocorticoids increase intracellular calcium concentrations in skeletal muscle and stimulate store-operated calcium entry (SOCE) and that these effects of glucocorticoids may at least in part be responsible for glucocorticoid-induced protein degradation. Treatment of cultured myotubes with dexamethasone, a frequently used in vitro model of muscle wasting, resulted in increased intracellular calcium concentrations determined by fura-2 AM fluorescence measurements. When SOCE was measured by using calcium “add-back” to muscle cells after depletion of intracellular calcium stores, results showed that SOCE was increased 15–25% by dexamethasone and that this response to dexamethasone was inhibited by the store-operated calcium channel blocker BTP2. Dexamethasone treatment stimulated the activity of calcium-independent phospholipase A2(iPLA2), and dexamethasone-induced increase in SOCE was reduced by the iPLA2inhibitor bromoenol lactone (BEL). In additional experiments, treatment of myotubes with the store-operated calcium channel inhibitor gadolinium ion or BEL reduced dexamethasone-induced increase in protein degradation. Taken together, the results suggest that glucocorticoids increase calcium concentrations in myocytes and stimulate iPLA2-dependent SOCE and that glucocorticoid-induced muscle protein degradation may at least in part be regulated by increased iPLA2activity, SOCE, and cellular calcium levels.

scholarly journals Store-operated calcium entry in physiology and pathology of mammalian cells.

2005 ◽  
Vol 52 (2) ◽  
pp. 397-409 ◽  
Author(s):  
Berenika Targos ◽  
Jolanta Barańska ◽  
Paweł Pomorski
Keyword(s):  
Cell Cycle ◽  
Calcium Level ◽  
Mammalian Cells ◽  
Long Term Potentiation ◽  
Calcium Entry ◽  
Neuroendocrine Cells ◽  
Calcium Stores ◽  
Excitable Cells ◽  
Store Operated Calcium Entry ◽  
Er Calcium

One of the numerous calcium-involving processes in mammalian cells is store-operated calcium entry (SOCE) -- the process in which depletion of calcium stores in the endoplasmic reticulum (ER) induces calcium influx from the extracellular space. Previously supposed to function only in non-excitable cells, SOCE is now known to play a role also in such excitable cells as neurons, muscles and neuroendocrine cells and is found in many different cell types. SOCE participates not only in processes dependent on ER calcium level but also specifically regulates some important processes such as cAMP production, T lymphocyte activation or induction of long-term potentiation. Impairment of SOCE can be an element of numerous disorders such as acute pancreatitis, primary immunodeficiency and, since it can take part in apoptosis or cell cycle regulation, SOCE may also be partially responsible for such serious disorders as Alzheimer disease and many types of cancer. Even disturbances in the 'servant' role of maintaining ER calcium level may cause serious effects because they can lead to ER homeostasis disturbance, influencing gene expression, protein synthesis and processing, and the cell cycle.

scholarly journals An essential and NSF independent role for α-SNAP in store-operated calcium entry

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Yong Miao ◽  
Cathrine Miner ◽  
Lei Zhang ◽  
Phyllis I Hanson ◽  
Adish Dani ◽  
...  
Keyword(s):  
Essential Role ◽  
Calcium Release ◽  
Calcium Entry ◽  
Snare Complex ◽  
Functional Coupling ◽  
Crac Channels ◽  
Store Depletion ◽  
Store Operated Calcium Entry ◽  
Crac Channel

Store-operated calcium entry (SOCE) by calcium release activated calcium (CRAC) channels constitutes a primary route of calcium entry in most cells. Orai1 forms the pore subunit of CRAC channels and Stim1 is the endoplasmic reticulum (ER) resident Ca2+ sensor. Upon store-depletion, Stim1 translocates to domains of ER adjacent to the plasma membrane where it interacts with and clusters Orai1 hexamers to form the CRAC channel complex. Molecular steps enabling activation of SOCE via CRAC channel clusters remain incompletely defined. Here we identify an essential role of α-SNAP in mediating functional coupling of Stim1 and Orai1 molecules to activate SOCE. This role for α-SNAP is direct and independent of its known activity in NSF dependent SNARE complex disassembly. Importantly, Stim1-Orai1 clustering still occurs in the absence of α-SNAP but its inability to support SOCE reveals that a previously unsuspected molecular re-arrangement within CRAC channel clusters is necessary for SOCE.

scholarly journals The KSR2-calcineurin complex regulates STIM1-ORAI1 dynamics and store-operated calcium entry (SOCE)

2014 ◽  
Vol 25 (11) ◽  
pp. 1769-1781 ◽  
Author(s):  
E. Giurisato ◽  
A. Gamberucci ◽  
C. Ulivieri ◽  
S. Marruganti ◽  
E. Rossi ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Calcium Entry ◽  
Significant Progress ◽  
Cytoskeleton Organization ◽  
Store Depletion ◽  
Kinase Suppressor Of Ras ◽  
Store Operated Calcium Entry ◽  
Calcineurin Activity ◽  
Entry Mechanism ◽  
Made In

Store-operated calcium entry (SOCE) is the predominant Ca2+ entry mechanism in nonexcitable cells and controls a variety of physiological and pathological processes. Although significant progress has been made in identifying the components required for SOCE, the molecular mechanisms underlying it are elusive. The present study provides evidence for a direct involvement of kinase suppressor of Ras 2 (KSR2) in SOCE. Using lymphocytes and fibroblasts from ksr2−/− mice and shKSR2-depleted cells, we find that KSR2 is critical for the elevation of cytosolic Ca2+ concentration. Specifically, our results show that although it is dispensable for Ca2+-store depletion, KSR2 is required for optimal calcium entry. We observe that KSR2 deficiency affects stromal interaction molecule 1 (STIM1)/ORAI1 puncta formation, which is correlated with cytoskeleton disorganization. Of interest, we find that KSR2-associated calcineurin is crucial for SOCE. Blocking calcineurin activity impairs STIM1/ORAI1 puncta-like formation and cytoskeleton organization. In addition, we observe that calcineurin activity and its role in SOCE are both KSR2 dependent.

E3-targeted anti-TRPC5 antibody inhibits store-operated calcium entry in freshly isolated pial arterioles

2006 ◽  
Vol 291 (6) ◽  
pp. H2653-H2659 ◽  
Author(s):  
Shang-Zhong Xu ◽  
Guylain Boulay ◽  
Richard Flemming ◽  
David J. Beech
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Transient Receptor Potential ◽  
Ionic Current ◽  
Receptor Potential ◽  
Muscle Cells ◽  
Calcium Entry ◽  
Store Depletion ◽  
Store Operated Calcium Entry ◽  
Transient Receptor

Smooth muscle cells in arterioles have pivotal roles in the determination of blood pressure and distribution of local blood flow. The cells exhibit calcium entry in response to passive store depletion, but the mechanisms and relevance of this phenomenon are poorly understood. Previously, a role for canonical transient receptor potential 1 (TRPC1) was indicated, but heterologous expression studies showed TRPC1 to have poor function in isolation, suggesting a requirement for additional proteins. Here we test the hypothesis that TRPC5 is such an additional protein, because TRPC5 forms heteromultimeric channels with TRPC1, and RNA encoding TRPC5 is present in arterioles. Recordings were from arteriolar fragments freshly isolated from rabbit pial membrane. Ionic current in response to store depletion has properties like that of the TRPC1/TRPC5 heteromultimer, and so the effect of the E3-targeted, externally acting, anti-TRPC5 blocking antibody (T5E3) was explored. T5E3 suppressed calcium entry in store-depleted arterioles but had no effect in the absence of store depletion. T5E3 preadsorbed to its antigenic peptide did not inhibit calcium entry. TRPC6 is commonly detected in smooth muscle and is present in the arterioles, but T5E3 had no effect on TRPC6. The data suggest that calcium entry occurring in response to passive store depletion in smooth muscle cells of arterioles involves TRPC5 as well as TRPC1.

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