scholarly journals Capacitative calcium entry

2005 ◽  
Vol 169 (3) ◽  
pp. 381-382 ◽  
Author(s):  
James W. Putney
Keyword(s):  
Plasma Membrane ◽  
Calcium Binding ◽  
Cell Biology ◽  
Essential Role ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Capacitative Calcium Entry ◽  
Calcium Store ◽  
Channel Regulation ◽  
Calcium Channel Regulation

A long-standing mystery in the cell biology of calcium channel regulation is the nature of the signal linking intracellular calcium stores to plasma membrane capacitative calcium entry channels. An RNAi-based screen of selected Drosophila genes has revealed that a calcium-binding protein, stromal interaction molecule (STIM), plays an essential role in the activation of these channels and may be the long sought sensor of calcium store content.

scholarly journals Junctate is a key element in calcium entry induced by activation of InsP3 receptors and/or calcium store depletion

2004 ◽  
Vol 166 (4) ◽  
pp. 537-548 ◽  
Author(s):  
Susan Treves ◽  
Clara Franzini-Armstrong ◽  
Luca Moccagatta ◽  
Christophe Arnoult ◽  
Cristiano Grasso ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Intracellular Calcium ◽  
Calcium Binding ◽  
Calcium Release ◽  
Transient Receptor Potential ◽  
Receptor Activation ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Store Depletion ◽  
Insp3 Receptors

In many cell types agonist-receptor activation leads to a rapid and transient release of Ca2+ from intracellular stores via activation of inositol 1,4,5 trisphosphate (InsP3) receptors (InsP3Rs). Stimulated cells activate store- or receptor-operated calcium channels localized in the plasma membrane, allowing entry of extracellular calcium into the cytoplasm, and thus replenishment of intracellular calcium stores. Calcium entry must be finely regulated in order to prevent an excessive intracellular calcium increase. Junctate, an integral calcium binding protein of endo(sarco)plasmic reticulum membrane, (a) induces and/or stabilizes peripheral couplings between the ER and the plasma membrane, and (b) forms a supramolecular complex with the InsP3R and the canonical transient receptor potential protein (TRPC) 3 calcium entry channel. The full-length protein modulates both agonist-induced and store depletion–induced calcium entry, whereas its NH2 terminus affects receptor-activated calcium entry. RNA interference to deplete cells of endogenous junctate, knocked down both agonist-activated calcium release from intracellular stores and calcium entry via TRPC3. These results demonstrate that junctate is a new protein involved in calcium homeostasis in eukaryotic cells.

scholarly journals Phosphatidylinositol(4,5)bisphosphate: diverse functions at the plasma membrane

2020 ◽  
Vol 64 (3) ◽  
pp. 513-531 ◽  
Author(s):  
Matilda Katan ◽  
Shamshad Cockcroft
Keyword(s):  
Plasma Membrane ◽  
Ion Channel ◽  
Tyrosine Kinases ◽  
Cell Biology ◽  
Second Messengers ◽  
Membrane Dynamics ◽  
Actin Dynamics ◽  
Ion Channel Regulation ◽  
Channel Regulation ◽  
Phosphoinositide 3 Kinase

Abstract Phosphatidylinositol(4,5) bisphosphate (PI(4,5)P2) has become a major focus in biochemistry, cell biology and physiology owing to its diverse functions at the plasma membrane. As a result, the functions of PI(4,5)P2 can be explored in two separate and distinct roles – as a substrate for phospholipase C (PLC) and phosphoinositide 3-kinase (PI3K) and as a primary messenger, each having unique properties. Thus PI(4,5)P2 makes contributions in both signal transduction and cellular processes including actin cytoskeleton dynamics, membrane dynamics and ion channel regulation. Signalling through plasma membrane G-protein coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immune receptors all use PI(4,5)P2 as a substrate to make second messengers. Activation of PI3K generates PI(3,4,5)P3 (phosphatidylinositol(3,4,5)trisphosphate), a lipid that recruits a plethora of proteins with pleckstrin homology (PH) domains to the plasma membrane to regulate multiple aspects of cellular function. In contrast, PLC activation results in the hydrolysis of PI(4,5)P2 to generate the second messengers, diacylglycerol (DAG), an activator of protein kinase C and inositol(1,4,5)trisphosphate (IP3/I(1,4,5)P3) which facilitates an increase in intracellular Ca2+. Decreases in PI(4,5)P2 by PLC also impact on functions that are dependent on the intact lipid and therefore endocytosis, actin dynamics and ion channel regulation are subject to control. Spatial organisation of PI(4,5)P2 in nanodomains at the membrane allows for these multiple processes to occur concurrently.

scholarly journals Capacitative Calcium Entry Deficits and Elevated Luminal Calcium Content in Mutant Presenilin-1 Knockin Mice

2000 ◽  
Vol 149 (4) ◽  
pp. 793-798 ◽  
Author(s):  
Malcolm A. Leissring ◽  
Yama Akbari ◽  
Christopher M. Fanger ◽  
Michael D. Cahalan ◽  
Mark P. Mattson ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Calcium Signaling ◽  
Intracellular Calcium ◽  
Brain Aging ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Capacitative Calcium Entry ◽  
Intracellular Calcium Stores ◽  
Agonist Stimulation

Dysregulation of calcium signaling has been causally implicated in brain aging and Alzheimer's disease. Mutations in the presenilin genes (PS1, PS2), the leading cause of autosomal dominant familial Alzheimer's disease (FAD), cause highly specific alterations in intracellular calcium signaling pathways that may contribute to the neurodegenerative and pathological lesions of the disease. To elucidate the cellular mechanisms underlying these disturbances, we studied calcium signaling in fibroblasts isolated from mutant PS1 knockin mice. Mutant PS1 knockin cells exhibited a marked potentiation in the amplitude of calcium transients evoked by agonist stimulation. These cells also showed significant impairments in capacitative calcium entry (CCE, also known as store-operated calcium entry), an important cellular signaling pathway wherein depletion of intracellular calcium stores triggers influx of extracellular calcium into the cytosol. Notably, deficits in CCE were evident after agonist stimulation, but not if intracellular calcium stores were completely depleted with thapsigargin. Treatment with ionomycin and thapsigargin revealed that calcium levels within the ER were significantly increased in mutant PS1 knockin cells. Collectively, our findings suggest that the overfilling of calcium stores represents the fundamental cellular defect underlying the alterations in calcium signaling conferred by presenilin mutations.

scholarly journals Putative capacitative calcium entry channels: expression of Drosophila trp and evidence for the existence of vertebrate homologues

1995 ◽  
Vol 311 (1) ◽  
pp. 41-44 ◽  
Author(s):  
C C Petersen ◽  
M J Berridge ◽  
M F Borgese ◽  
D L Bennett
Keyword(s):  
Intracellular Calcium ◽  
Xenopus Oocytes ◽  
Transient Receptor Potential ◽  
Calcium Entry ◽  
Calcium Stores ◽  
Pcr Cloning ◽  
Capacitative Calcium Entry ◽  
Homologous Proteins ◽  
Major Pathway ◽  
Intracellular Calcium Stores

Capacitative calcium entry is a major pathway through which intracellular calcium stores are refilled after stimulation. It has been suggested that the protein encoded by the transient receptor potential (trp) gene expressed in Drosophila photoreceptors may be homologous with capacitative calcium entry channels. Expression of the trp gene product in Xenopus oocytes led to significant increases in calcium entry only when the intracellular calcium stores were depleted. Previous investigations have found trp to be uniquely expressed in Drosophila photoreceptors, but PCR cloning shows that homologous proteins exist in Calliphora, mouse brain and Xenopus oocytes. It is thus possible that capacitative calcium entry in Xenopus oocytes is mediated by a homologue of trp.

scholarly journals Voltage-Dependent Calcium Channels, Calcium Binding Proteins, and Their Interaction in the Pathological Process of Epilepsy

2018 ◽  
Vol 19 (9) ◽  
pp. 2735 ◽  
Author(s):  
Jie-Hua Xu ◽  
Feng-Ru Tang
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Intracellular Calcium ◽  
Calcium Binding ◽  
Pathological Process ◽  
Calcium Binding Proteins ◽  
Calcium Store ◽  
Intracellular Calcium Store ◽  
Voltage Dependent ◽  
Voltage Dependent Calcium Channels

As an important second messenger, the calcium ion (Ca2+) plays a vital role in normal brain function and in the pathophysiological process of different neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), and epilepsy. Ca2+ takes part in the regulation of neuronal excitability, and the imbalance of intracellular Ca2+ is a trigger factor for the occurrence of epilepsy. Several anti-epileptic drugs target voltage-dependent calcium channels (VDCCs). Intracellular Ca2+ levels are mainly controlled by VDCCs located in the plasma membrane, the calcium-binding proteins (CBPs) inside the cytoplasm, calcium channels located on the intracellular calcium store (particular the endoplasmic reticulum/sarcoplasmic reticulum), and the Ca2+-pumps located in the plasma membrane and intracellular calcium store. So far, while many studies have established the relationship between calcium control factors and epilepsy, the mechanism of various Ca2+ regulatory factors in epileptogenesis is still unknown. In this paper, we reviewed the function, distribution, and alteration of VDCCs and CBPs in the central nervous system in the pathological process of epilepsy. The interaction of VDCCs with CBPs in the pathological process of epilepsy was also summarized. We hope this review can provide some clues for better understanding the mechanism of epileptogenesis, and for the development of new anti-epileptic drugs targeting on VDCCs and CBPs.

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