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Cell Calcium

Sabine Nafzger, Jean-Sebastien Rougier
AIM: The L-type voltage-gated calcium channel Cav1.2 mediates the calcium influx into cells upon membrane depolarization. The list of cardiopathies associated to Cav1.2 dysfunctions highlights the importance of this channel in cardiac physiology. Calcium/calmodulin-dependent serine protein kinase (CASK), expressed in cardiac cells, has been identified as a regulator of Cav2.2 channels in neurons, but no experiments have been performed to investigate its role in Cav1.2 regulation. METHODS AND RESULTS: Full length or the distal C-terminal truncated of the pore-forming Cav1...
October 5, 2016: Cell Calcium
Akitoshi Miyamoto, Kotomi Sugiura, Katsukiko Mikoshiba
Monitoring the dynamic patterns of intracellular signaling molecules, such as inositol 1,4,5-trisphosphate (IP3) and Ca(2+), that control many diverse cellular processes, provides us significant information to understand the regulatory mechanism of cellular functions. For searching more sensitive and higher dynamic range probes for signaling molecules, convenient and supersensitive high throughput screening systems are required. Here we show the optimal "in Escherichia coli (E. coli) colony" screening method based on the twin-arginine translocase (Tat) pathway and introduce a novel application of a confocal microscope as a supersensitive detection system to measure changes in the fluorescence intensity of fluorescent probes in E...
October 1, 2016: Cell Calcium
Andrei Rozov, Nail Burnashev
Suppression of NMDA receptor (NMDAR)-mediated currents by intracellular Ca(2+) has been described as a negative feedback loop in NMDAR modulation. In the time scale of tenths of milliseconds the depth of the suppression does not depend on the Ca(2+) source. It may be caused by Ca(2+) influx through voltage-gated calcium channels, NMDAR channels or release from intracellular stores. However, NMDARs are often co-expressed in synapses with Ca(2+)-permeable AMPA receptors (AMPARs). Due to significant differences in activation kinetics between these two types of glutamate receptors (GluRs), Ca(2+) entry through AMPARs precedes full activation of NMDARs, and therefore, might have an impact on the amplitude of NMDAR-mediated currents...
September 28, 2016: Cell Calcium
Laura Korvers, Amanda de Andrade Costa, Martin Mersch, Vitali Matyash, Helmut Kettenmann, Marcus Semtner
Microglia are the resident immune cells in the central nervous system and many of their physiological functions are known to be linked to intracellular calcium (Ca(2+)) signaling. Here we show that isolated and purified mouse microglia-either freshly or cultured-display spontaneous and transient Ca(2+) elevations lasting for around ten to twenty seconds and occurring at frequencies of around five to ten events per hour and cell. The events were absent after depletion of internal Ca(2+) stores, by phospholipase C (PLC) inhibition or blockade of inositol-1,4,5-trisphosphate receptors (IP3Rs), but not by removal of extracellular Ca(2+), indicating that Ca(2+) is released from endoplasmic reticulum intracellular stores...
September 22, 2016: Cell Calcium
James P Barger, Patrick F Dillon
The dehydration of ion-water complexes prior to ion channel transit has focused on channel protein-mediated dissociation of water. Ion dehydration by the membrane electric field has not previously been considered. Near membrane electric fields have previously been shown to cause the disassociation of non-covalently bound small molecule-small molecule, small molecule-protein, and protein-protein complexes. It is well known that cosmotropic, structure making ions such as calcium and sodium significantly bind multiple water ions in solution...
September 22, 2016: Cell Calcium
Stacey Ann N D'mello, Wayne R Joseph, Taryn N Green, Euphemia Y Leung, Matthew J During, Graeme J Finlay, Bruce C Baguley, Maggie L Kalev-Zylinska
GRIN2A mutations are frequent in melanoma tumours but their role in disease is not well understood. GRIN2A encodes a modulatory subunit of the N-methyl-d-aspartate receptor (NMDAR). We hypothesized that certain GRIN2A mutations increase NMDAR function and support melanoma growth through oncogenic effects. This hypothesis was tested using 19 low-passage melanoma cell lines, four of which carried novel missense mutations in GRIN2A that we previously reported. We examined NMDAR expression, function of a calcium ion (Ca(2+)) channel and its contribution to cell growth using pharmacological modulators; findings were correlated with the presence or absence of GRIN2A mutations...
September 14, 2016: Cell Calcium
Sophie Lepannetier, Nadège Zanou, Xavier Yerna, Noémie Emeriau, Inès Dufour, Julien Masquelier, Giulio Muccioli, Nicolas Tajeddine, Philippe Gailly
TRP channels are involved in the control of a broad range of cellular functions such as cell proliferation and motility. We investigated the gating mechanism of TRPC1 channel and its role in U251 glioblastoma cells migration in response to chemotaxis by platelet-derived growth factor (PDGF). PDGF induced an influx of Ca(2+) that was partially inhibited after pretreatment of the cells with SKI-II, a specific inhibitor of sphingosine kinase producing sphingosine-1-P (S1P). S1P by itself also induced an entry of Ca(2+)...
September 9, 2016: Cell Calcium
Richard Gordan, Nadezhda Fefelova, Judith K Gwathmey, Lai-Hua Xie
In the present study, we have used a genetic mouse model that lacks cyclophilin D (CypD KO) to assess the cardioprotective effect of mitochondrial permeability transition pore (mPTP) inhibition on Ca(2+) waves and Ca(2+) alternans at the single cell level, and cardiac arrhythmias in whole-heart preparations. The protonophore carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) caused mitochondrial membrane potential depolarization to the same extent in cardiomyocytes from both WT and CypD KO mice, however, cardiomyocytes from CypD KO mice exhibited significantly less mPTP opening than cardiomyocytes from WT mice (p<0...
September 2, 2016: Cell Calcium
Sreeram Ravi, Karina A Peña, Charleen T Chu, Kirill Kiselyov
Oxidative stress drives cell death in a number of diseases including ischemic stroke and neurodegenerative diseases. A better understanding of how cells recover from oxidative stress is likely to lead to better treatments for stroke and other diseases. The recent evidence obtained in several models ties the process of lysosomal exocytosis to the clearance of protein aggregates and toxic metals. The mechanisms that regulate lysosomal exocytosis, under normal or pathological conditions, are only beginning to emerge...
August 29, 2016: Cell Calcium
Ekaterina A Ivanova, Mohamed A Elmonem, Inge Bongaerts, Tomas Luyten, Ludwig Missiaen, Lambertus P van den Heuvel, Elena N Levtchenko, Geert Bultynck
Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder caused by loss-of-function mutations in the CTNS gene coding for the lysosomal cystine transporter, cystinosin. Recent studies have demonstrated that, apart from cystine accumulation in the lysosomes, cystinosin-deficient cells, especially renal proximal tubular epithelial cells are characterized by abnormal vesicle trafficking and endocytosis, possible lysosomal dysfunction and perturbed intracellular signalling cascades. It is therefore possible that Ca(2+) signalling is disturbed in cystinosis, as it has been demonstrated for other disorders associated with lysosomal dysfunction, such as Gaucher, Niemann-Pick type C and Alzheimer's diseases...
October 2016: Cell Calcium
Pável Vázquez, Aldo Tirado-Cortés, Rocío Álvarez, Michel Ronjat, Araceli Amaya, Alicia Ortega
The mechanism underlying fatigue in skeletal muscle (SM) related to the redox-potential hypothesis, ranges from a direct effect of oxygen reactive species, to a number of other free radical intermediates targeting specific amino acids in the Ca(2+)-regulatory proteins of the sarcoplasmic reticulum (SR). In the present study, we investigate the selective oxidation/reduction of the protein motif Cys-(Xn=2-6)-Cys, known as a vicinal thiol group (VTG), present in the SR Ca(2+)-ATPase (SERCA) and in the Ca(2+)-channel ryanodine receptor (RyR) which are modified during muscle fatigue in SM...
October 2016: Cell Calcium
Jeffrey T Lock, Ian Parker, Ian F Smith
Tunneling membrane nanotubes (TNTs) are thin membrane projections linking cell bodies separated by many micrometers, which are proposed to mediate signaling and even transfer of cytosolic contents between distant cells. Several reports describe propagation of Ca(2+) signals between distant cells via TNTs, but the underlying mechanisms remain poorly understood. Utilizing a HeLa M-Sec cell line engineered to upregulate TNTs we replicated previous findings that mechanical stimulation elicits robust cytosolic Ca(2+) elevations that propagate to surrounding, physically separate cells...
October 2016: Cell Calcium
Xiao-Xu Chen, Jia-Hua Zhang, Bin-Hua Pan, Hui-Li Ren, Xiu-Ling Feng, Jia-Ling Wang, Jun-Hua Xiao
Airway remodeling is a histopathological hallmark of chronic respiratory diseases that includes airway smooth muscle cell (ASMC) proliferation. Canonical transient receptor potential channel-3 (TRPC3)-encoded nonselective cation channels (NSCCs) are important native constitutively active channels that play significant roles in physiological and pathological conditions in ASMCs. Lipopolysaccharides (LPSs), known as lipoglycans and endotoxin, have been proven to be inducers of airway remodeling, though the mechanisms remain unclear...
October 2016: Cell Calcium
Kazuhisa Hirabayashi, Kenjiro Hanaoka, Takahiro Egawa, Chiaki Kobayashi, Shodai Takahashi, Toru Komatsu, Tasuku Ueno, Takuya Terai, Yuji Ikegaya, Tetsuo Nagano, Yasuteru Urano
Fluorescence imaging of calcium ions (Ca(2+)) has become an essential technique for investigation of signaling pathways involving Ca(2+) as a second messenger. But, Ca(2+) signaling is involved in many biological phenomena, and therefore simultaneous visualization of Ca(2+) and other biomolecules (multicolor imaging) would be particularly informative. For this purpose, we set out to develop a fluorescent probe for Ca(2+) that would operate in a different color region (red) from that of probes for other molecules, many of which show green fluorescence, as exemplified by green fluorescent protein (GFP)...
October 2016: Cell Calcium
Asya Makhro, Thomas Haider, Jue Wang, Nikolay Bogdanov, Patrick Steffen, Christian Wagner, Tim Meyer, Max Gassmann, Anne Hecksteden, Lars Kaestner, Anna Bogdanova
The N-methyl d-aspartate receptors (NMDARs) mediating Ca(2+) uptake upon stimulation with glutamate and glycine were recently discovered in red blood cells (RBC) of healthy humans. Activation of these receptors with agonists triggered transient Ca(2+)-dependent decrease in hemoglobin oxygen affinity in RBC suspension. The aim of this study was to assess the potential physiological relevance of this phenomenon. Two groups formed by either healthy untrained volunteers or endurance athletes were subjected to a stepwise incremental cycling test to exhaustion...
October 2016: Cell Calcium
Indu S Ambudkar, Shmuel Muallem
No abstract text is available yet for this article.
September 2016: Cell Calcium
Prashant Mishra
In the cellular context, mitochondria display a number of dynamic behaviors including fusion, division (or fission), directed transport, and targeted destruction (mitophagy). The relevance of these processes to human diseases has been intensively studied over the last several years, and emphasize the importance of mitochondrial dynamics to the central nervous system. Intriguingly, a common theme is that these behaviors do not function in isolation, but influence one another either directly or indirectly. Here, we review the dynamic properties of mitochondria and summarize their relationships to human diseases...
September 2016: Cell Calcium
David N Criddle
Disruption of Ca(2+) homeostasis can lead to severe damage of the pancreas, resulting in premature activation of digestive enzymes, vacuolisation and necrotic cell death, features typical of acute pancreatitis (AP). Therefore a fine balance between Ca(2+) release from internal stores, Ca(2+) entry and extrusion mechanisms is necessary to avoid injury. Precipitants of AP induce Ca(2+) overload of the pancreatic acinar cell that causes mitochondrial dysfunction, via formation of the mitochondrial permeability transition pore (MPTP), loss of ATP production and consequent necrosis...
September 2016: Cell Calcium
Amit U Joshi, Opher S Kornfeld, Daria Mochly-Rosen
Endoplasmic reticulum (ER) and mitochondrial function have both been shown to be critical events in neurodegenerative diseases. The ER mediates protein folding, maturation, sorting as well acts as calcium storage. The unfolded protein response (UPR) is a stress response of the ER that is activated by the accumulation of misfolded proteins within the ER lumen. Although the molecular mechanisms underlying ER stress-induced apoptosis are not completely understood, increasing evidence suggests that ER and mitochondria cooperate to signal cell death...
September 2016: Cell Calcium
Alessandra Magenta, Elena Dellambra, Roberta Ciarapica, Maurizio C Capogrossi
Reactive oxygen species increase cytosolic [Ca(2+)], (Cai), and also modulate the expression of some microRNAs (miRNAs), however the link among oxidative stress, miRNAs and Cai is poorly characterized. In this review we have focused on three groups of miRNAs: (a) miRNAs that are modulated both by ROS and Cai: miR-181a and miR-205; (b) miRNAs that are modulated by ROS and have an effect on Cai: miR-1, miR-21, miR-24, miR-25, miR-185 and miR-214; (c) miRNAs that modulate both ROS and Cai: miR-133; miR-145, miR-495, and we have analyzed their effects on cell signaling and cell function...
September 2016: Cell Calcium
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