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S100A13 and S100A6 exhibit distinct translocation pathways in endothelial cells.

S100 proteins have attracted great interest in recent years because of their cell- and tissue-specific expression and association with various human pathologies. Most S100 proteins are small acidic proteins with calcium-binding domains - the EF hands. It is thought that this group of proteins carry out their cellular functions by interacting with specific target proteins, an interaction that is mainly dependent on exposure of hydrophobic patches, which result from calcium binding. S100A13, one of the most recently identified members of the S100 family, is expressed in various tissues. Interest

On calcium-buffer dynamics within the excess buffer regime.

In intracellular calcium signaling, calcium buffers has been recognized for their role in reshaping and localizing the calcium concentration profile in the vicinity of the channel, as well as reducing the effective diffusion of free calcium. In the presence of an excess of endogenous or exogenous buffers, linearization of the reaction-diffusion system describing the calcium-buffer dynamics has been instrumental in understanding the extent of the microdomain formation and in quantifying the apparent diffusion of the free calcium. In these linearized models, the conclusions are usually drawn fro…

EGCG suppressed activation of hepatic stellate cells by regulating the PLCE1/IP3/Ca2+ pathway.

(-)-Epigallocatechin-3-O-gallate (EGCG), one of the green tea catechins, exhibits significant antioxidant properties that play an essential … ed novel evidence regarding the regulatory effects of EGCG on activated HSCs (aHSCs) in mice by the calcium signaling pathway, emphasizing the crucial role of PLCE1 within the calcium signaling network of HSCs. The proposition was also made that PLCE1 holds promise as a novel therapeutic target for murine liver fibrosis.

Visualizing calcium responses to acetylcholine convection along endothelium of arteriolar networks in Cx40BAC-GCaMP2 transgenic mice.

Acetylcholine evokes endothelium-dependent vasodilation subsequent to a rise in intracellular calcium. Despite widespread application in human and animal studies, calcium responses to intravascular ACh have not been visualized in vivo. Microiontophoresis of ACh in tissue adjacent to an arteriole activates abluminal muscarinic receptors on endothelial cells within a "Локально" region of diffusion, but it is unknown whether ACh released in such fashion gains access to the flow stream resulting in further actions downstream. To test this hypothesis and provide new insight into calcium signaling in v…

Host-derived stimuli alter intracellular calcium levels in Pseudomonas aeruginosa, revealing its potential role as a second messenger.

Calcium signaling is a fundamental cellular communication mechanism, well established in eukaryotes, that relies on calcium ions (Ca2+) acting both as first and second messengers to regulate diverse life-sustaining processes. In bacteria, although the significance of Ca2+ regulation is recognized, it is commonly attributed to its role as a first messenger, while the mechanistic basis for its capacity as a second messenger remains elusive. Previously, we have shown that Pseudomonas aeruginosa, an opportunistic pathogen causing life-threatening infections in humans, possesses the key prerequisit…

The Dually Localized EF-Hand Domain-Containing Protein TgEFP1 Regulates the Lytic Cycle of Toxoplasma gondii.

The propagation of the obligate intracellular parasite Toxoplasma gondii is tightly regulated by calcium signaling. However, the mechanisms by which calcium homeostasis and fluxes are regulated in this human pathogen are not fully understood. To identify Toxoplasma's calcium homeostasis network, we have characterized a novel EF-hand domain-containing protein, which we have named TgEFP1. We have determined that TgEFP1 localizes to a previously described compartment known as the plant-like vacuole or the endosomal-like compartment (PLV/ELC), which harbors several proteins related to ionic regula…

Calcium regulation in protozoan parasites.

The calcium ion (Ca(2+)) is used as a major signaling molecule in a diverse range of eukaryotic cells including several human parasitic protozoa, such as Trypanosoma cruzi, Trypanosoma brucei, Leishmania spp, Plasmodium spp, Toxoplasma gondii, Cryptosporidium parvum, Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis. Ca(2+) is critical for invasion of intracellular parasites, and its cytosolic concentration is regulated by the concerted operation of several transporters present in the plasma membrane, endoplasmic reticulum, mitochondria and acidocalcisomes. Recent findings have

Role of the calcium-sensing receptor in parathyroid gland physiology.

The calcium-sensing receptor (CaSR) represents the molecular mechanism by which parathyroid cells detect changes in blood ionized calcium concentration and modulate parathyroid hormone (PTH) secretion to maintain serum calcium levels within a narrow physiological range. Much has been learned in recent years about the diversity of signal transduction through the CaSR and the various factors that affect receptor expression. Beyond its classic role as a determinant of calcium-regulated PTH secretion, signaling through the CaSR also influences both gene transcription and cell proliferation in para

Importance of arachidonic acid as a mediator of parathyroid gland response.

The intracellular signaling mechanisms that mediate the regulation of parathyroid hormone (PTH) secretion by parathyroid glands are becoming increasingly more understood. Extracellular calcium modulates parathyroid function by acting on a G protein-coupled calcium-sensing receptor, which activates the hydrolysis of membrane phospholipids by phospholipases C, D, and A2 to generate intracellular signals. Arachidonic acid (AA) produced by phospholiphase A2 (PLA2) appears to play a crucial role throughout the generation of downstream-oxygenated products. Recent studies demonstrate the activation o

Intracellular Calcium Responses to External Calcium Stimuli in Dictyostelium.

Intracellular calcium (Ca2+) plays a vital role in numerous cellular processes, including signal transduction, cell motility, and development. Despite extensive research on intracellular calcium dynamics, the specific mechanisms by which extracellular calcium influences intracellular calcium levels remain unclear. In this study, we generated a Dictyostelium-specific plasmid expressing the calcium biosensor GCaMP3 and visualized real-time intracellular calcium fluctuations in live cells. In response to external calcium, vegetative cells displayed a rapid and transient increase in intracellular

Extrasynaptic neuron-glia communication: The how and why.

Chemical synaptic transmission between neurons is believed to take place at specialized sites of cell contact, comprising presynaptic termin … adjacent glial cells. These calcium transients were coupled to vasoresponses, indicating that glial calcium signaling mediates neurovascular coupling not only in synaptic brain regions such as gray matter, but also in brain regions devoid of synapses.

Exploring the role of CaMKII in exercise-induced cardioprotection.

Regular physical exercise can induce a multifaceted cardioprotective phenotype characterized by improved Ca2⁺ handling, mitochondrial resilience, redox buffering, autonomic regulation, and resistance to ischemia-reperfusion injury. Ca2⁺/calmodulin-dependent protein kinase II (CaMKII), particularly cardiac CaMKIIδ, is positioned at the intersection of these adaptive and maladaptive responses because it couples repetitive Ca2⁺ oscillations to excitation-contraction coupling, ion-channel regulation, transcriptional remodeling, mitochondrial stress signaling, and cell-death pathways. Current evide

Effects of calpain inhibitor on the apoptosis of hepatic stellate cells induced by calcium ionophore A23187.

We previously showed that changes in calcium concentrations were related to cell apoptosis in vitro. The endoplasmic reticulum (ER) is the main component of calcium storage and signal transduction, and disrupting the balance of intracellular Ca2+ can cause endoplasmic reticulum stress (ERS). In this process, the ER releases stored Ca 2+ into the cytoplasm and activates calpain-2. To further investigate the effect of calpain in hepatic stellate cells (HSCs), in the current study, we examine the effect of N-acetyl-leu-leu-norleucinal (ALLN) on apoptosis resulting from calcium ionophore A23187-in

Митохондрийская эндоплазмическая ретикулумная мембрана и ионный обмен кальция: новое направление для старения и нейродегенеративных заболеваний.

Митохондрийские эндоплазмические ретикулумные мембраны служат важнейшими сигнальными узлами, координирующими связь между эндоплазмическим ретикулумом и митохондрией, и играют центральную роль в ионном обмене кальциями. Этот динамический интерфейс регулирует ключевые клеточные процессы, включая биоэнергетический метаболизм, апоптоз, автофагию и реакцию на стресс. Регулирование переноса кальция, связанного с митохондрией эндоплазмической ретикулумной мембраной, может нарушить внутриклеточный гомеостаз, что приводит к дисфункции митохондриала, окислительному стрессу и нейрональной смерти, которые

Совпадение в аннотации оригинала
Mitochondria-associated endoplasmic reticulum membranes serve as crucial signaling hubs mediating communication between the endoplasmic reti … xes within mitochondria-associated endoplasmic reticulum membranes and the pathogenic mechanisms of calcium signaling regulated by these membranes in neurodegenerative disorders. It places particular emphasis on structural alterations in calcium ion transport machinery as a common mechanism underlying various neurodegenerative diseases. In Alzheimer's disease, mito …

Role of Nitric Oxide in the Altered Calcium Homeostasis of Platelets from Rats with Biliary Cirrhosis.

INTRODUCTION: Previously, we found that intracellular calcium (Ca2+) homeostasis is altered in platelets from an experimental model of liver cirrhosis, namely the bile-duct-ligated (BDL) rat. These alterations are compatible with the existence of a hypercoagulable state. OBJECTIVE: In the present study, we analyzed the role of nitric oxide in the abnormal calcium signaling responses of an experimental cirrhosis model, the bile duct-ligated rat. METHODS: Chronic treatment with L-NAME was used to inhibit NO production in a group of control and BDL animals, and the responses compared to those o…

Role of Nox4 in High Calcium-Induced Renal Oxidative Stress Damage and Crystal Deposition.

Aims: We aimed at exploring the role of nicotinamide adenine dinucleotide phosphate oxidase subunit 4 (Nox4) in the regulation of hypercalciuria-induced renal oxidative damage and crystal depositions. Results: High calcium activated Nox4 expression through protein kinase C (PKC). Downregulation of Nox4 expression attenuated hypercalciuria-induced osteoblast-associated protein expression, oxidative stress injury, and crystal deposition in rat kidneys of 1,25-dihydroxyvitamin D3 (VitD) urolithiasis model. Further, calcium-induced activation of mitogen-activated protein kinase (MAPK), overexpress

Altered endoplasmic reticulum calcium loading in human PLN-R14del cardiomyopathy.

The phospholamban (PLN) R14del genetic variant causes dilated cardiomyopathy. Previous studies suggest involvement of the ER stress response and impairment of ER-related signaling pathways such as autophagy. In this study, human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) from an unrelated control subject, a PLN-R14del patient, and a corresponding isogenic control were transduced with adeno-associated virus serotype 6 (AAV6) encoding the endoplasmic reticulum calcium sensor CEPIAer. Indicator compounds for the modulation of ER calcium homeostasis showed similar character

Activity of Human-Specific Interlaminar Astrocytes in a Chimeric Mouse Model of Fragile X Syndrome.

Astrocytes, a subtype of glial cells, have multiple roles in regulating neuronal development and homeostasis. In addition to the typical mammalian astrocytes, in the primate cortex, interlaminar astrocytes are located in the superficial layer and project long processes traversing multiple layers of the cerebral cortex. Previously, we described a human stem cell based chimeric mouse model where interlaminar astrocytes develop. Here, we utilized this model to study the calcium signaling properties of interlaminar astrocytes. To determine how interlaminar astrocytes could contribute to neurodevel…

Population-scale analysis of frequency-dependent calcium dynamics in retinal ganglion cells under electric field stimulation.

Electric field (EF) stimulation is an emerging neuromodulatory strategy for promoting the repair and functional recovery of degenerated neur … mental–computational framework, we reveal how electric field stimulation modulates population-level calcium signaling in retinal ganglion cells, enabling simultaneous characterization of spatial response patterns and ensemble-averaged activity across thousands of cells. At this scale, RGC calcium responses are constrained to a distinct frequency regime: low frequen …

Cardioluminescence in Transgenic Zebrafish Larvae: A Calcium Imaging Tool to Study Drug Effects and Pathological Modeling.

Zebrafish embryos and larvae have emerged as an excellent model in cardiovascular research and are amenable to live imaging with genetically encoded biosensors to study cardiac cell behaviours, including calcium dynamics. To monitor calcium ion levels in three to five days post-fertilization larvae, we have used bioluminescence. We generated a transgenic line expressing GFP-aequorin in the heart, Tg(myl7:GA), and optimized a reconstitution protocol to boost aequorin luminescence. The analogue diacetylh-coelenterazine enhanced light output and signal-to-noise ratio. With this cardioluminescence