Articles de revues : « Calcium sensor proteins »

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D. Burgoyne, Robert. « The neuronal calcium-sensor proteins ». Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1742, n^o 1-3 (décembre 2004) : 59–68. http://dx.doi.org/10.1016/j.bbamcr.2004.08.008.

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Hams, Nicole, Murugesh Padmanarayana, Weihong Qiu et Colin P. Johnson. « Otoferlin is a multivalent calcium-sensitive scaffold linking SNAREs and calcium channels ». Proceedings of the National Academy of Sciences 114, n^o 30 (10 juillet 2017) : 8023–28. http://dx.doi.org/10.1073/pnas.1703240114.

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Sensory hair cells rely on otoferlin as the calcium sensor for exocytosis and encoding of sound preferentially over the neuronal calcium sensor synaptotagmin. Although it is established that synaptotagmin cannot rescue the otoferlin KO phenotype, the large size and low solubility of otoferlin have prohibited direct biochemical comparisons that could establish functional differences between these two proteins. To address this challenge, we have developed a single-molecule colocalization binding titration assay (smCoBRA) that can quantitatively characterize full-length otoferlin from mammalian cell lysate. Using smCoBRA, we found that, although both otoferlin and synaptotagmin bind membrane fusion SNARE proteins, only otoferlin interacts with the L-type calcium channel Cav1.3, showing a significant difference between the synaptic proteins. Furthermore, otoferlin was found capable of interacting with multiple SNARE and Cav1.3 proteins simultaneously, forming a heterooligomer complex. We also found that a deafness-causing missense mutation in otoferlin attenuates binding between otoferlin and Cav1.3, suggesting that deficiencies in this interaction may form the basis for otoferlin-related hearing loss. Based on our results, we propose a model in which otoferlin acts as a calcium-sensitive scaffolding protein, localizing SNARE proteins proximal to the calcium channel so as to synchronize calcium influx with membrane fusion. Our findings also provide a molecular-level explanation for the observation that synaptotagmin and otoferlin are not functionally redundant. This study also validates a generally applicable methodology for quantitatively characterizing large, multivalent membrane proteins.

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Badura, Aleksandra, Xiaonan Richard Sun, Andrea Giovannucci, Laura A. Lynch et Samuel S. H. Wang. « Fast calcium sensor proteins for monitoring neural activity ». Neurophotonics 1, n^o 2 (17 octobre 2014) : 025008. http://dx.doi.org/10.1117/1.nph.1.2.025008.

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O'Callaghan, D. W., et R. D. Burgoyne. « Role of myristoylation in the intracellular targeting of neuronal calcium sensor (NCS) proteins ». Biochemical Society Transactions 31, n^o 5 (1 octobre 2003) : 963–65. http://dx.doi.org/10.1042/bst0310963.

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The control of the intracellular localization of NCS (neuronal calcium sensor) proteins is of importance for their ability to respond appropriately to differing calcium signals. We examine the localization of three NCS proteins: NCS-1, KChIP-1 (potassium-channel-interacting protein 1) and hippocalcin. Additionally, the [Ca2+] dependency of the calcium-induced translocation of hippocalcin is investigated. The implications of the differential targeting of these proteins on calcium signal interpretation are considered.

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BURGOYNE, Robert D., et Jamie L. WEISS. « The neuronal calcium sensor family of Ca2+-binding proteins ». Biochemical Journal 353, n^o 1 (1 janvier 2000) : 1. http://dx.doi.org/10.1042/0264-6021:3530001.

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BURGOYNE, R. D., et J. L. WEISS. « The neuronal calcium sensor family of Ca2+-binding proteins ». Biochemical Journal 354, n^o 3 (15 mars 2001) : 727. http://dx.doi.org/10.1042/0264-6021:3540727v.

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BURGOYNE, Robert D., et Jamie L. WEISS. « The neuronal calcium sensor family of Ca2+-binding proteins ». Biochemical Journal 353, n^o 1 (18 décembre 2000) : 1–12. http://dx.doi.org/10.1042/bj3530001.

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Ca2+ plays a central role in the function of neurons as the trigger for neurotransmitter release, and many aspects of neuronal activity, from rapid modulation to changes in gene expression, are controlled by Ca2+. These actions of Ca2+ must be mediated by Ca2+-binding proteins, including calmodulin, which is involved in Ca2+ regulation, not only in neurons, but in most other cell types. A large number of other EF-hand-containing Ca2+-binding proteins are known. One family of these, the neuronal calcium sensor (NCS) proteins, has a restricted expression in retinal photoreceptors or neurons and neuroendocrine cells, suggesting that they have specialized roles in these cell types. Two members of the family (recoverin and guanylate cyclase-activating protein) have established roles in the regulation of phototransduction. Despite close sequence similarities, the NCS proteins have distinct neuronal distributions, suggesting that they have different functions. Recent work has begun to demonstrate the physiological roles of members of this protein family. These include roles in the modulation of neurotransmitter release, control of cyclic nucleotide metabolism, biosynthesis of polyphosphoinositides, regulation of gene expression and in the direct regulation of ion channels. In the present review we describe the known sequences and structures of the NCS proteins, information on their interactions with target proteins and current knowledge about their cellular and physiological functions.

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BURGOYNE, R. D., et J. L. WEISS. « The neuronal calcium sensor family of Ca2+-binding proteins ». Biochemical Journal 354, n^o 3 (8 mars 2001) : 727. http://dx.doi.org/10.1042/bj3540727v.

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Sorkin, Raya, Margherita Marchetti, Emma Logtenberg, Emma Kerklingh, Guy Brand, Rashmi Voleti, Josep Rizo, Wouter H. Roos, Alexander J. Groffen et Gijs J. L. Wuite. « Membrane Binding, Bending and Remodeling by Calcium Sensor Proteins ». Biophysical Journal 116, n^o 3 (février 2019) : 368a. http://dx.doi.org/10.1016/j.bpj.2018.11.2002.

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Zimmer, Danna B., Jeannine O. Eubanks, Dhivya Ramakrishnan et Michael F. Criscitiello. « Evolution of the S100 family of calcium sensor proteins ». Cell Calcium 53, n^o 3 (mars 2013) : 170–79. http://dx.doi.org/10.1016/j.ceca.2012.11.006.

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Hilfiker, S. « Neuronal calcium sensor-1 : a multifunctional regulator of secretion ». Biochemical Society Transactions 31, n^o 4 (1 août 2003) : 828–32. http://dx.doi.org/10.1042/bst0310828.

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Ca2+ ions play a crucial role not only as the trigger for neurotransmitter release, but also in other aspects of brain function, such as short-term and long-term modulation of synaptic efficacy, which may underlie certain forms of learning and memory. The actions of Ca2+ are mediated by Ca2+-binding proteins, including a group of proteins known as neuronal calcium sensor (NCS) proteins. The NCS family includes NCS-1, visinin-like proteins, recoverins, guanylate cyclase-activating proteins and potassium channel-interacting proteins. Some members of this family, such as recoverin and guanylate cyclase-activating protein, are only expressed in photoreceptor cells and have been implicated in the control of visual transduction pathways, while the functional roles of the other members are largely unknown. NCS-1 was originally identified in Drosophila in a screen for neuronal hyperexcitability mutants. NCS-1 is an N-terminally myristoylated protein that contains four EF-hand motifs, three of which are able to bind Ca2+ in the submicromolar range. Overexpression of NCS-1 has been shown to enhance evoked neurotransmitter release, paired-pulse facilitation and exocytosis in several neuronal and neuroendocrine cell types. Recent experiments suggest that NCS-1 interacts directly with phosphatidylinositol 4-hydroxykinase in yeast as well as mammalian cells, suggesting that it may enhance neuronal secretion by modulating cellular trafficking steps in a phosphoinositide-dependent manner. In contrast, an involvement of NCS-1 in the expression and regulation of voltage-gated Ca2+ channels and K+ channels has also been proposed, which may be attributed, at least in part, to the effects of NCS-1 on vesicular trafficking pathways. The present review describes current knowledge about the cellular functions and molecular mechanisms by which NCS-1 may regulate neurotransmitter release.

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Roelse, Margriet, Ron Wehrens, Maurice Gl Henquet, Renger F. Witkamp, Robert D. Hall et Maarten A. Jongsma. « The Effect of Calcium Buffering and Calcium Sensor Type on the Sensitivity of an Array-Based Bitter Receptor Screening Assay ». Chemical Senses 44, n^o 7 (5 juillet 2019) : 497–505. http://dx.doi.org/10.1093/chemse/bjz044.

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Abstract The genetically encoded calcium sensor protein Cameleon YC3.6 has previously been applied for functional G protein–coupled receptor screening using receptor cell arrays. However, different types of sensors are available, with a wide range in [Ca2+] sensitivity, Hill coefficients, calcium binding domains, and fluorophores, which could potentially improve the performance of the assay. Here, we compared the responses of 3 structurally different calcium sensor proteins (Cameleon YC3.6, Nano140, and Twitch2B) simultaneously, on a single chip, at different cytosolic expression levels and in combination with 2 different bitter receptors, TAS2R8 and TAS2R14. Sensor concentrations were modified by varying the amount of calcium sensor DNA that was printed on the DNA arrays prior to reverse transfection. We found that ~2-fold lower concentrations of calcium sensor protein, by transfecting 4 times less sensor-coding DNA, resulted in more sensitive bitter responses. The best results were obtained with Twitch2B, where, relative to YC3.6 at the default DNA concentration, a 4-fold lower DNA concentration increased sensitivity 60-fold and signal strength 5- to 10-fold. Next, we compared the performance of YC3.6 and Twitch2B against an array with 11 different bitter taste receptors. We observed a 2- to 8-fold increase in sensitivity using Twitch2B compared with YC3.6. The bitter receptor arrays contained 300 spots and could be exposed to a series of 18 injections within 1 h resulting in 5400 measurements. These optimized sensor conditions provide a basis for enhancing receptomics calcium assays for receptors with poor Ca2+ signaling and will benefit future high-throughput receptomics experiments.

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Braunewell, Karl-Heinz, et Eckart D. Gundelfinger. « Intracellular neuronal calcium sensor proteins : a family of EF-hand calcium-binding proteins in search of a function ». Cell and Tissue Research 295, n^o 1 (1 janvier 1999) : 1–12. http://dx.doi.org/10.1007/s004410051207.

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Burgoyne, Robert D., et Lee P. Haynes. « Understanding the physiological roles of the neuronal calcium sensor proteins ». Molecular Brain 5, n^o 1 (2012) : 2. http://dx.doi.org/10.1186/1756-6606-5-2.

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Burgoyne, Robert D. « Neuronal calcium sensor proteins : generating diversity in neuronal Ca2+ signalling ». Nature Reviews Neuroscience 8, n^o 3 (mars 2007) : 182–93. http://dx.doi.org/10.1038/nrn2093.

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Ames, James B., et Sunghyuk Lim. « Molecular structure and target recognition of neuronal calcium sensor proteins ». Biochimica et Biophysica Acta (BBA) - General Subjects 1820, n^o 8 (août 2012) : 1205–13. http://dx.doi.org/10.1016/j.bbagen.2011.10.003.

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Sulmann, Stefan, Daniele Dell'Orco, Valerio Marino, Petra Behnen et Karl-Wilhelm Koch. « Conformational Changes in Calcium-Sensor Proteins under Molecular Crowding Conditions ». Chemistry - A European Journal 20, n^o 22 (27 mars 2014) : 6756–62. http://dx.doi.org/10.1002/chem.201402146.

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Amici, Mascia, Andrew Doherty, Jihoon Jo, David Jane, Kwangwook Cho, Graham Collingridge et Sheila Dargan. « Neuronal calcium sensors and synaptic plasticity ». Biochemical Society Transactions 37, n^o 6 (19 novembre 2009) : 1359–63. http://dx.doi.org/10.1042/bst0371359.

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Calcium entry plays a major role in the induction of several forms of synaptic plasticity in different areas of the central nervous system. The spatiotemporal aspects of these calcium signals can determine the type of synaptic plasticity induced, e.g. LTP (long-term potentiation) or LTD (long-term depression). A vast amount of research has been conducted to identify the molecular and cellular signalling pathways underlying LTP and LTD, but many components remain to be identified. Calcium sensor proteins are thought to play an essential role in regulating the initial part of synaptic plasticity signalling pathways. However, there is still a significant gap in knowledge, and it is only recently that evidence for the importance of members of the NCS (neuronal calcium sensor) protein family has started to emerge. The present minireview aims to bring together evidence supporting a role for NCS proteins in plasticity, focusing on emerging roles of NCS-1 and hippocalcin.

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Smith, Steven P., et Gary S. Shaw. « A change-in-hand mechanism for S100 signalling ». Biochemistry and Cell Biology 76, n^o 2-3 (1 mai 1998) : 324–33. http://dx.doi.org/10.1139/o98-062.

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S100 proteins are a group of small dimeric calcium-binding proteins making up a large subclass of the EF-hand family of calcium-binding proteins. Members of this family of proteins have been proposed to act as intracellular calcium modulatory proteins in a fashion analogous to that of the EF-hand sensor proteins troponin-C and calmodulin. Recently, NMR spectroscopy has provided the three-dimensional structures of the S100 family members S100A6 and S100B in both the apo- and calcium-bound forms. These structures have allowed for the identification of a novel calcium-induced conformational change termed the change-in-hand mechanism. Helix III of the C-terminal calcium-binding loop changes its helix-helix interactions (or handness) with the remainder of the molecule primarily owing to the reorientation of the backbone in an effort to coordinate the calcium ion. This reorientation of helix III exposes several residues in the C-terminus and linker regions of S100B resulting in the formation of a hydrophobic patch surrounded be a number of acidic residues. This site is the proposed region for protein-protein recognition.Key words: S100, calcium-binding protein, EF-hand, conformational change.

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OKADA, Miki, Daisuke TAKEZAWA, Shuji TACHIBANAKI, Satoru KAWAMURA, Hiroshi TOKUMITSU et Ryoji KOBAYASHI. « Neuronal calcium sensor proteins are direct targets of the insulinotropic agent repaglinide ». Biochemical Journal 375, n^o 1 (1 octobre 2003) : 87–97. http://dx.doi.org/10.1042/bj20030376.

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The NCS (neuronal calcium sensor) proteins, including neurocalcins, recoverins and visinin-like proteins are members of a family of Ca2+-sensitive regulators, each with three Ca2+-binding EF-hand motifs. In plants, lily CCaMK [chimaeric Ca2+/CaM (calmodulin)-dependent protein kinase] and its PpCaMK (Physcomitrella patens CCaMK) homologue are characterized by a visinin-like domain with three EF-hands. In the present study, in an effort to discover NCS antagonists, we screened a total of 43 compounds using Ca2+-dependent drug affinity chromatography and found that the insulinotropic agent repaglinide targets the NCS protein family. Repaglinide was found to bind to NCS proteins, but not to CaM or S100 proteins, in a Ca2+-dependent manner. Furthermore, the drug antagonized the inhibitory action of recoverin in a rhodopsin kinase assay with IC50 values of 400 μM. Moreover, repaglinide tightly bound to the visinin-like domain of CCaMK and PpCaMK in a Ca2+-dependent manner and antagonized the regulatory function of the domain with IC50 values of 55 and 4 μM for CCaMK and PpCaMK respectively. Although both repaglinide and a potent insulin secretagogue, namely glibenclamide, blocked KATP channels with similar potency, glibenclamide had no antagonizing effect on the Ca2+-stimulated CCaMK and PpCaMK autophosphorylation, mediated by their visinin-like domain. In addition, a typical CaM antagonist, trifluoperazine, had no effect on the CCaMK and PpCaMK autophosphorylation. Repaglinide appears to be the first antagonist of NCS proteins and visinin-like domain-bearing enzymes. It may serve as a useful tool for evaluating the physiological functions of the NCS protein family. In addition, since repaglinide selectively targets NCS proteins among the EF-hand Ca2+-binding proteins, it is a potential lead compound for the development of more potent NCS antagonists.

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Viviano, Jeffrey, Anuradha Krishnan, Hao Wu et Venkat Venkataraman. « Electrophoretic mobility shift in native gels indicates calcium-dependent structural changes of neuronal calcium sensor proteins ». Analytical Biochemistry 494 (février 2016) : 93–100. http://dx.doi.org/10.1016/j.ab.2015.11.005.

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Gustavsson, Natalia, et Weiping Han. « Calcium-sensing beyond neurotransmitters : functions of synaptotagmins in neuroendocrine and endocrine secretion ». Bioscience Reports 29, n^o 4 (8 juin 2009) : 245–59. http://dx.doi.org/10.1042/bsr20090031.

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Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin–calcium-sensor paradigm, that is, members of the synaptotagmin family function as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion. Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems.

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McCue, H. V., L. P. Haynes et R. D. Burgoyne. « The Diversity of Calcium Sensor Proteins in the Regulation of Neuronal Function ». Cold Spring Harbor Perspectives in Biology 2, n^o 8 (28 juillet 2010) : a004085. http://dx.doi.org/10.1101/cshperspect.a004085.

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IACOVELLI, LUISA, MICHELE SALLESE, STEFANIA MARIGGIò et ANTONIO DE BLASI. « Regulation of G‐protein‐coupled receptor kinase subtypes by calcium sensor proteins ». FASEB Journal 13, n^o 1 (janvier 1999) : 1–8. http://dx.doi.org/10.1096/fasebj.13.1.1.

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Sallese, Michele, Luisa Iacovelli, Albana Cumashi, Loredana Capobianco, Laura Cuomo et Antonio De Blasi. « Regulation of G protein-coupled receptor kinase subtypes by calcium sensor proteins ». Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 1498, n^o 2-3 (décembre 2000) : 112–21. http://dx.doi.org/10.1016/s0167-4889(00)00088-4.

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McLachlan, D., J. Kudla, J. Schroeder et A. Hetherington. « Roles of calcium sensor proteins CBL9 and CBL1 in guard cell signalling ». Comparative Biochemistry and Physiology Part A : Molecular & ; Integrative Physiology 150, n^o 3 (juillet 2008) : S194. http://dx.doi.org/10.1016/j.cbpa.2008.04.533.

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Grise, Florence, Nada Taib, Carole Monterrat, Valérie Lagrée et Jochen Lang. « Distinct roles of the C2A and the C2B domain of the vesicular Ca2+ sensor synaptotagmin 9 in endocrine β-cells ». Biochemical Journal 403, n^o 3 (12 avril 2007) : 483–92. http://dx.doi.org/10.1042/bj20061182.

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Synaptotagmins form a family of calcium-sensor proteins implicated in exocytosis, and these vesicular transmembrane proteins are endowed with two cytosolic calcium-binding C2 domains, C2A and C2B. Whereas the isoforms syt1 and syt2 have been studied in detail, less is known about syt9, the calcium sensor involved in endocrine secretion such as insulin release from large dense core vesicles in pancreatic β-cells. Using cell-based assays to closely mimic physiological conditions, we observed SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor)-independent translocation of syt9C2AB to the plasma membrane at calcium levels corresponding to endocrine exocytosis, followed by internalization to endosomes. The use of point mutants and truncations revealed that initial translocation required only the C2A domain, whereas the C2B domain ensured partial pre-binding of syt9C2AB to the membrane and post-stimulatory localization to endosomes. In contrast with the known properties of neuronal and neuroendocrine syt1 or syt2, the C2B domain of syt9 did not undergo calcium-dependent membrane binding despite a high degree of structural homology as observed through molecular modelling. The present study demonstrates distinct intracellular properties of syt9 with different roles for each C2 domain in endocrine cells.

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Kumar, Vaishali, et Shuvadeep Maity. « ER Stress-Sensor Proteins and ER-Mitochondrial Crosstalk—Signaling Beyond (ER) Stress Response ». Biomolecules 11, n^o 2 (28 janvier 2021) : 173. http://dx.doi.org/10.3390/biom11020173.

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Recent studies undoubtedly show the importance of inter organellar connections to maintain cellular homeostasis. In normal physiological conditions or in the presence of cellular and environmental stress, each organelle responds alone or in coordination to maintain cellular function. The Endoplasmic reticulum (ER) and mitochondria are two important organelles with very specialized structural and functional properties. These two organelles are physically connected through very specialized proteins in the region called the mitochondria-associated ER membrane (MAM). The molecular foundation of this relationship is complex and involves not only ion homeostasis through the shuttling of calcium but also many structural and apoptotic proteins. IRE1alpha and PERK are known for their canonical function as an ER stress sensor controlling unfolded protein response during ER stress. The presence of these transmembrane proteins at the MAM indicates its potential involvement in other biological functions beyond ER stress signaling. Many recent studies have now focused on the non-canonical function of these sensors. In this review, we will focus on ER mitochondrial interdependence with special emphasis on the non-canonical role of ER stress sensors beyond ER stress.

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Johnson, Colin P., et Edwin R. Chapman. « Otoferlin is a calcium sensor that directly regulates SNARE-mediated membrane fusion ». Journal of Cell Biology 191, n^o 1 (4 octobre 2010) : 187–97. http://dx.doi.org/10.1083/jcb.201002089.

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Otoferlin is a large multi–C2 domain protein proposed to act as a calcium sensor that regulates synaptic vesicle exocytosis in cochlear hair cells. Although mutations in otoferlin have been associated with deafness, its contribution to neurotransmitter release is unresolved. Using recombinant proteins, we demonstrate that five of the six C2 domains of otoferlin sense calcium with apparent dissociation constants that ranged from 13–25 µM; in the presence of membranes, these apparent affinities increase by up to sevenfold. Using a reconstituted membrane fusion assay, we found that five of the six C2 domains of otoferlin stimulate membrane fusion in a calcium-dependent manner. We also demonstrate that a calcium binding–deficient form of the C2C domain is incapable of stimulating membrane fusion, further underscoring the importance of calcium for the protein’s function. These results demonstrate for the first time that otoferlin is a calcium sensor that can directly regulate soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor–mediated membrane fusion reactions.

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DeFalco, Thomas A., Kyle W. Bender et Wayne A. Snedden. « Breaking the code : Ca2+ sensors in plant signalling ». Biochemical Journal 425, n^o 1 (14 décembre 2009) : 27–40. http://dx.doi.org/10.1042/bj20091147.

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Ca2+ ions play a vital role as second messengers in plant cells during various developmental processes and in response to environmental stimuli. Plants have evolved a diversity of unique proteins that bind Ca2+ using the evolutionarily conserved EF-hand motif. The currently held hypothesis is that these proteins function as Ca2+ sensors by undergoing conformational changes in response to Ca2+-binding that facilitate their regulation of target proteins and thereby co-ordinate various signalling pathways. The three main classes of these EF-hand Ca2+sensors in plants are CaMs [calmodulins; including CMLs (CaM-like proteins)], CDPKs (calcium-dependent protein kinases) and CBLs (calcineurin B-like proteins). In the plant species examined to date, each of these classes is represented by a large family of proteins, most of which have not been characterized biochemically and whose physiological roles remain unclear. In the present review, we discuss recent advances in research on CaMs and CMLs, CDPKs and CBLs, and we attempt to integrate the current knowledge on the different sensor classes into common physiological themes.

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Kumar, Manoj, Komal Sharma, Akhilesh K. Yadav, Kajal Kanchan, Madhu Baghel, Suneel Kateriya et Girdhar K. Pandey. « Genome-wide identification and biochemical characterization of calcineurin B-like calcium sensor proteins in Chlamydomonas reinhardtii ». Biochemical Journal 477, n^o 10 (28 mai 2020) : 1879–92. http://dx.doi.org/10.1042/bcj20190960.

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Calcium (Ca2+) signaling is involved in the regulation of diverse biological functions through association with several proteins that enable them to respond to abiotic and biotic stresses. Though Ca2+-dependent signaling has been implicated in the regulation of several physiological processes in Chlamydomonas reinhardtii, Ca2+ sensor proteins are not characterized completely. C. reinhardtii has diverged from land plants lineage, but shares many common genes with animals, particularly those encoding proteins of the eukaryotic flagellum (or cilium) along with the basal body. Calcineurin, a Ca2+/calmodulin-dependent protein phosphatase, is an important effector of Ca2+ signaling in animals, while calcineurin B-like proteins (CBLs) play an important role in Ca2+ sensing and signaling in plants. The present study led to the identification of 13 novel CBL-like Ca2+ sensors in C. reinhardtii genome. One of the archetypical genes of the newly identified candidate, CrCBL-like1 was characterized. The ability of CrCBL-like1 protein to sense as well as bind Ca2+ were validated using two-step Ca2+-binding kinetics. The CrCBL-like1 protein localized around the plasma membrane, basal bodies and in flagella, and interacted with voltage-gated Ca2+ channel protein present abundantly in the flagella, indicating its involvement in the regulation of the Ca2+ concentration for flagellar movement. The CrCBL-like1 transcript and protein expression were also found to respond to abiotic stresses, suggesting its involvement in diverse physiological processes. Thus, the present study identifies novel Ca2+ sensors and sheds light on key players involved in Ca2+signaling in C. reinhardtii, which could further be extrapolated to understand the evolution of Ca2+ mediated signaling in other eukaryotes.

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Mahal, Lara K., Sonia M. Sequeira, Jodi M. Gureasko et Thomas H. Söllner. « Calcium-independent stimulation of membrane fusion and SNAREpin formation by synaptotagmin I ». Journal of Cell Biology 158, n^o 2 (15 juillet 2002) : 273–82. http://dx.doi.org/10.1083/jcb.200203135.

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Ñeurotransmitter release requires the direct coupling of the calcium sensor with the machinery for membrane fusion. SNARE proteins comprise the minimal fusion machinery, and synaptotagmin I, a synaptic vesicle protein, is the primary candidate for the main neuronal calcium sensor. To test the effect of synaptotagmin I on membrane fusion, we incorporated it into a SNARE-mediated liposome fusion assay. Synaptotagmin I dramatically stimulated membrane fusion by facilitating SNAREpin zippering. This stimulatory effect was topologically restricted to v-SNARE vesicles (containing VAMP 2) and only occurred in trans to t-SNARE vesicles (containing syntaxin 1A and SNAP-25). Interestingly, calcium did not affect the overall fusion reaction. These results indicate that synaptotagmin I can directly accelerate SNARE-mediated membrane fusion and raise the possibility that additional components might be required to ensure tight calcium coupling.

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Hoshijima, Masahiko. « Mechanical stress-strain sensors embedded in cardiac cytoskeleton : Z disk, titin, and associated structures ». American Journal of Physiology-Heart and Circulatory Physiology 290, n^o 4 (avril 2006) : H1313—H1325. http://dx.doi.org/10.1152/ajpheart.00816.2005.

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Cardiac muscle is equipped with intricate intrinsic mechanisms to regulate adaptive remodeling. Recent and extensive experimental findings powered by novel strategies for screening protein-protein interactions, improved imaging technologies, and versatile transgenic mouse methodologies reveal that Z disks and titin filaments possess unexpectedly complicated sensory and modulatory mechanisms for signal reception and transduction. These mechanisms employ molecules such as muscle-enriched LIM domain proteins, PDZ-LIM domain proteins, myozenin gene family members, titin-associated ankyrin repeat family proteins, and muscle-specific ring finger proteins, which have been identified as potential molecular sensor components. Moreover, classic transmembrane signaling processes, including mitogen-activated kinase, protein kinase C, and calcium signaling, also involve novel interactions with the Z disk/titin network. This compartmentalization of signaling complexes permits alteration of receptor-dependent transcriptional regulation by direct sensing of intrinsic stress. Newly identified mechanical stress sensors are not limited to Z-disk region and to I-band and M-band regions of titin but are also embedded in muscle-specific membrane systems such as the costamere, intercalated disks, and caveolae-like microdomains. This review summarizes current knowledge of this rapidly developing area with focus on how the heart adjusts physiological remodeling process to meet with mechanical demands and how this process fails in cardiac pathologies.

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Bourne, Yves, Jens Dannenberg, Verena Pollmann, Pascale Marchot et Olaf Pongs. « Immunocytochemical Localization and Crystal Structure of Human Frequenin (Neuronal Calcium Sensor 1) ». Journal of Biological Chemistry 276, n^o 15 (22 novembre 2000) : 11949–55. http://dx.doi.org/10.1074/jbc.m009373200.

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Frequenin, a member of a large family of myristoyl-switch calcium-binding proteins, functions as a calcium-ion sensor to modulate synaptic activity and secretion. We show that human frequenin colocalizes with ARF1 GTPase in COS-7 cells and occurs in similar cellular compartments as the phosphatidylinositol-4-OH kinase PI4Kβ, the mammalian homolog of the yeast kinase PIK1. In addition, the crystal structure of unmyristoylated, calcium-bound human frequenin has been determined and refined to 1.9 Å resolution. The overall fold of frequenin resembles those of neurocalcin and the photoreceptor, recoverin, of the same family, with two pairs of calcium-binding EF hands and three bound calcium ions. Despite the similarities, however, frequenin displays significant structural differences. A large conformational shift of the C-terminal region creates a wide hydrophobic crevice at the surface of frequenin. This crevice, which is unique to frequenin and distinct from the myristoyl-binding box of recoverin, may accommodate a yet unknown protein ligand.

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Fitzgerald, Daniel J., Robert D. Burgoyne et Lee P. Haynes. « Neuronal calcium sensor proteins are unable to modulate NFAT activation in mammalian cells ». Biochimica et Biophysica Acta (BBA) - General Subjects 1780, n^o 2 (février 2008) : 240–48. http://dx.doi.org/10.1016/j.bbagen.2007.10.011.

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Nelson, Melanie R., et Walter J. Chazin. « An interaction-based analysis of calcium-induced conformational changes in Ca2+ sensor proteins ». Protein Science 7, n^o 2 (février 1998) : 270–82. http://dx.doi.org/10.1002/pro.5560070206.

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Seagar, Michael, Christian Lévêque, Nathalie Charvin, Beatrice Marquèze, Nicole Martin–Moutot, Jeanne Andrée Boudier, Jean–Louis Boudier, Yoko Shoji-Kasai, Kazuki Sato et Masami Takahashi. « Interactions between proteins implicated in exocytosis and voltage–gated calcium channels ». Philosophical Transactions of the Royal Society of London. Series B : Biological Sciences 354, n^o 1381 (28 février 1999) : 289–97. http://dx.doi.org/10.1098/rstb.1999.0380.

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Neurotransmitter release from synaptic vesicles is triggered by voltage–gated calcium influx through P/Q–type or N–type calcium channels. Purification of N–type channels from rat brain synaptosomes initially suggested molecular interactions between calcium channels and two key proteins implicated in exocytosis: synaptotagmin I and syntaxin 1. Co–immunoprecipitation experiments were consistent with the hypothesis that both N– and P/Q–type calcium channels, but not L–type channels, are associated with the 7S complex containing syntaxin 1, SNAP–25, VAMP and synaptotagmin I or II. Immunofluorescence confocal microscopy at the frog neuromuscular junction confirmed that calcium channels, syntaxin 1 and SNAP–25 are co–localized at active zones of the presynaptic plasma membrane where transmitter release occurs. Experiments with recombinant proteins were performed to map synaptic protein interaction sites on the α 1 A subunit, which forms the pore of the P/Q–type calcium channel. In vitro –translated 35 S–synaptotagmin I bound to a site located on the cytoplasmic loop linking homologous domains II and III of the α 1 A subunit. This direct link would target synaptotagmin, a putative calcium sensor for exocytosis, to a microdomain of calcium influx close to the channel mouth. Cysteine string proteins (CSPs) contain a J–domain characteristic of molecular chaperones that co–operate with Hsp70. They are located on synaptic vesicles and thought to be involved in modulating the acticity of presynaptic calcium channels. CSPs were found to bind to the same domain of the calcium channel as synaptotagmin, and also to associate with VAMP. CSPs may act as molecular chaperones in association with Hsp70 to direct assembly or dissociation of multi–protein complexes at the calcium channel.

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Chernorudskiy, Alexander, Ersilia Varone, Sara Francesca Colombo, Stefano Fumagalli, Alfredo Cagnotto, Angela Cattaneo, Mickael Briens et al. « Selenoprotein N is an endoplasmic reticulum calcium sensor that links luminal calcium levels to a redox activity ». Proceedings of the National Academy of Sciences 117, n^o 35 (17 août 2020) : 21288–98. http://dx.doi.org/10.1073/pnas.2003847117.

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The endoplasmic reticulum (ER) is the reservoir for calcium in cells. Luminal calcium levels are determined by calcium-sensing proteins that trigger calcium dynamics in response to calcium fluctuations. Here we report that Selenoprotein N (SEPN1) is a type II transmembrane protein that senses ER calcium fluctuations by binding this ion through a luminal EF-hand domain. In vitro and in vivo experiments show that via this domain, SEPN1 responds to diminished luminal calcium levels, dynamically changing its oligomeric state and enhancing its redox-dependent interaction with cellular partners, including the ER calcium pump sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA). Importantly, single amino acid substitutions in the EF-hand domain of SEPN1 identified as clinical variations are shown to impair its calcium-binding and calcium-dependent structural changes, suggesting a key role of the EF-hand domain in SEPN1 function. In conclusion, SEPN1 is a ER calcium sensor that responds to luminal calcium depletion, changing its oligomeric state and acting as a reductase to refill ER calcium stores.

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Dizhoor, Alexander M., et Igor V. Peshenko. « Regulation of retinal membrane guanylyl cyclase (RetGC) by negative calcium feedback and RD3 protein ». Pflügers Archiv - European Journal of Physiology 473, n^o 9 (3 février 2021) : 1393–410. http://dx.doi.org/10.1007/s00424-021-02523-4.

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AbstractThis article presents a brief overview of the main biochemical and cellular processes involved in regulation of cyclic GMP production in photoreceptors. The main focus is on how the fluctuations of free calcium concentrations in photoreceptors between light and dark regulate the activity of retinal membrane guanylyl cyclase (RetGC) via calcium sensor proteins. The emphasis of the review is on the structure of RetGC and guanylyl cyclase activating proteins (GCAPs) in relation to their functional role in photoreceptors and congenital diseases of photoreceptors. In addition to that, the structure and function of retinal degeneration-3 protein (RD3), which regulates RetGC in a calcium-independent manner, is discussed in detail in connections with its role in photoreceptor biology and inherited retinal blindness.

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Villalobos, C., et R. Andrade. « Visinin-Like Neuronal Calcium Sensor Proteins Regulate the Slow Calcium-Activated Afterhyperpolarizing Current in the Rat Cerebral Cortex ». Journal of Neuroscience 30, n^o 43 (27 octobre 2010) : 14361–65. http://dx.doi.org/10.1523/jneurosci.3440-10.2010.

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Vladimirov, Vasiliy I., Viktoriia E. Baksheeva, Irina V. Mikhailova, Ramis G. Ismailov, Ekaterina A. Litus, Natalia K. Tikhomirova, Aliya A. Nazipova, Sergei E. Permyakov, Evgeni Yu Zernii et Dmitry V. Zinchenko. « A Novel Approach to Bacterial Expression and Purification of Myristoylated Forms of Neuronal Calcium Sensor Proteins ». Biomolecules 10, n^o 7 (10 juillet 2020) : 1025. http://dx.doi.org/10.3390/biom10071025.

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N-terminal myristoylation is a common co-and post-translational modification of numerous eukaryotic and viral proteins, which affects their interaction with lipids and partner proteins, thereby modulating various cellular processes. Among those are neuronal calcium sensor (NCS) proteins, mediating transduction of calcium signals in a wide range of regulatory cascades, including reception, neurotransmission, neuronal growth and survival. The details of NCSs functioning are of special interest due to their involvement in the progression of ophthalmological and neurodegenerative diseases and their role in cancer. The well-established procedures for preparation of native-like myristoylated forms of recombinant NCSs via their bacterial co-expression with N-myristoyl transferase from Saccharomyces cerevisiae often yield a mixture of the myristoylated and non-myristoylated forms. Here, we report a novel approach to preparation of several NCSs, including recoverin, GCAP1, GCAP2, neurocalcin δ and NCS-1, ensuring their nearly complete N-myristoylation. The optimized bacterial expression and myristoylation of the NCSs is followed by a set of procedures for separation of their myristoylated and non-myristoylated forms using a combination of hydrophobic interaction chromatography steps. We demonstrate that the refolded and further purified myristoylated NCS-1 maintains its Ca2+-binding ability and stability of tertiary structure. The developed approach is generally suited for preparation of other myristoylated proteins.

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Baram, Dana, Michal Linial, Yoseph A. Mekori et Ronit Sagi-Eisenberg. « Cutting Edge : Ca2+-Dependent Exocytosis in Mast Cells Is Stimulated by the Ca2+ Sensor, Synaptotagmin I ». Journal of Immunology 161, n^o 10 (15 novembre 1998) : 5120–23. http://dx.doi.org/10.4049/jimmunol.161.10.5120.

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Abstract Mast cells secrete a variety of biologically active substances that mediate inflammatory responses. Synaptotagmin(s) (Syts) are a gene family of proteins that are implicated in the control of Ca2+-dependent exocytosis. In the present study, we investigated the possible occurrence and functional involvement of Syt in the control of mast cell exocytosis. Here, we demonstrate that both connective tissue type and mucosal-like mast cells express Syt-immunoreactive proteins, and that these proteins are localized almost exclusively to their secretory granules. Furthermore, expression of Syt I, the neuronal Ca2+ sensor, in rat basophilic leukemia cells (RBL-2H3), a tumor analogue of mucosal mast cells, resulted in prominent potentiation and acceleration of Ca2+-dependent exocytosis. Therefore, these findings implicate Syt as a Ca2+ sensor that mediates regulated secretion in mast cells to calcium ionophore.

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MacDougall, Daniel D., Zesen Lin, Nara L. Chon, Skyler L. Jackman, Hai Lin, Jefferson D. Knight et Arun Anantharam. « The high-affinity calcium sensor synaptotagmin-7 serves multiple roles in regulated exocytosis ». Journal of General Physiology 150, n^o 6 (24 mai 2018) : 783–807. http://dx.doi.org/10.1085/jgp.201711944.

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Synaptotagmin (Syt) proteins comprise a 17-member family, many of which trigger exocytosis in response to calcium. Historically, most studies have focused on the isoform Syt-1, which serves as the primary calcium sensor in synchronous neurotransmitter release. Recently, Syt-7 has become a topic of broad interest because of its extreme calcium sensitivity and diversity of roles in a wide range of cell types. Here, we review the known and emerging roles of Syt-7 in various contexts and stress the importance of its actions. Unique functions of Syt-7 are discussed in light of recent imaging, electrophysiological, and computational studies. Particular emphasis is placed on Syt-7–dependent regulation of synaptic transmission and neuroendocrine cell secretion. Finally, based on biochemical and structural data, we propose a mechanism to link Syt-7’s role in membrane fusion with its role in subsequent fusion pore expansion via strong calcium-dependent phospholipid binding.

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Beech, D. J. « Bipolar phospholipid sensing by TRPC5 calcium channel ». Biochemical Society Transactions 35, n^o 1 (22 janvier 2007) : 101–4. http://dx.doi.org/10.1042/bst0350101.

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TRPC5 [TRP (transient receptor potential) canonical (or classical) 5] is a widely expressed mammalian homologue of Drosophila TRP, forming a calcium- and sodium-permeable channel in the plasma membrane either as a homomultimer or heteromultimer with other proteins (e.g. TRPC1). Although several factors are known to stimulate the channel, understanding of its endogenous activators and functions is limited. This paper provides a brief and focused review of our latest findings that show that TRPC5 is a sensor of important signalling phospholipids, including lysophosphatidylcholine and sphingosine 1-phosphate, acting extracellularly or intracellularly. Underlying mechanisms of action and biological relevance are discussed.

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Roderick, H. L., et M. D. Bootman. « Bi-directional signalling from the InsP3 receptor : regulation by calcium and accessory factors ». Biochemical Society Transactions 31, n^o 5 (1 octobre 2003) : 950–53. http://dx.doi.org/10.1042/bst0310950.

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Calcium is a pleiotropic messenger controlling a diverse array of intracellular events from fertilization to cell death. One of the main mechanisms by which intracellular calcium is elevated is through InsP3 [Ins(1,4,5)P3]-induced mobilization of calcium from its receptor on the endoplasmic reticulum calcium store. The activity of the InsP3R (InsP3 receptor) is subject to regulation by many factors other than InsP3, most notably calcium itself, which regulates the channel in a bell-shaped dependent manner. InsP3R sensitivity is also regulated by post-translational modifications such as phosphorylation and by binding of accessory proteins. Taken together it appears that the InsP3R can be regarded as a cellular sensor for many signalling pathways, qualitatively and quantitatively regulating intracellular calcium signals with consequences for downstream cellular physiology.

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O’Day, Danton H. « Calmodulin Binding Domains in Critical Risk Proteins Involved in Neurodegeneration ». Current Issues in Molecular Biology 44, n^o 11 (21 novembre 2022) : 5802–14. http://dx.doi.org/10.3390/cimb44110394.

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Neurodegeneration leads to multiple early changes in cognitive, emotional, and social behaviours and ultimately progresses to dementia. The dysregulation of calcium is one of the earliest potentially initiating events in the development of neurodegenerative diseases. A primary neuronal target of calcium is the small sensor and effector protein calmodulin that, in response to calcium levels, binds to and regulates hundreds of calmodulin binding proteins. The intimate and entangled relationship between calmodulin binding proteins and all phases of Alzheimer’s disease has been established, but the relationship to other neurodegenerative diseases is just beginning to be evaluated. Risk factors and hallmark proteins from Parkinson’s disease (PD; SNCA, Parkin, PINK1, LRRK2, PARK7), Huntington’s disease (HD; Htt, TGM1, TGM2), Lewy Body disease (LBD; TMEM175, GBA), and amyotrophic lateral sclerosis/frontotemporal disease (ALS/FTD; VCP, FUS, TDP-43, TBK1, C90rf72, SQSTM1, CHCHD10, SOD1) were scanned for the presence of calmodulin binding domains and, within them, appropriate binding motifs. Binding domains and motifs were identified in multiple risk proteins, some of which are involved in multiple neurodegenerative diseases. The potential calmodulin binding profiles for risk proteins involved in HD, PD, LBD, and ALS/FTD coupled with other studies on proven binding proteins supports the central and potentially critical role for calmodulin in neurodegenerative events.

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Barr, Valarie A., Kelsie M. Bernot, Sonal Srikanth, Yousang Gwack, Lakshmi Balagopalan, Carole K. Regan, Daniel J. Helman et al. « Dynamic Movement of the Calcium Sensor STIM1 and the Calcium Channel Orai1 in Activated T-Cells : Puncta and Distal Caps ». Molecular Biology of the Cell 19, n^o 7 (juillet 2008) : 2802–17. http://dx.doi.org/10.1091/mbc.e08-02-0146.

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The proteins STIM1 and Orai1 are the long sought components of the store-operated channels required in T-cell activation. However, little is known about the interaction of these proteins in T-cells after engagement of the T-cell receptor. We found that T-cell receptor engagement caused STIM1 and Orai1 to colocalize in puncta near the site of stimulation and accumulate in a dense structure on the opposite side of the T-cell. FRET measurements showed a close interaction between STIM1 and Orai1 both in the puncta and in the dense cap-like structure. The formation of cap-like structures did not entail rearrangement of the entire endoplasmic reticulum. Cap formation depended on TCR engagement and tyrosine phosphorylation, but not on channel activity or Ca2+ influx. These caps were very dynamic in T-cells activated by contact with superantigen pulsed B-cells and could move from the distal pole to an existing or a newly forming immunological synapse. One function of this cap may be to provide preassembled Ca2+ channel components to existing and newly forming immunological synapses.

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Hira, Tohru, Hiroshi Hara, Fusao Tomita et Yoritaka Aoyama. « Casein Binds to the Cell Membrane and Induces Intracellular Calcium Signals in the Enteroendocrine Cell : A Brief Communication ». Experimental Biology and Medicine 228, n^o 7 (juillet 2003) : 850–54. http://dx.doi.org/10.1177/15353702-0322807-11.

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Dietary protein but not amino acids stimulates cholecystokinin (CCK) secretion in rat mucosal cells. However, the dietary protein sensory mechanisms and the intracellular signal pathway in the enteroendocrine cells have not yet been clarified. The relationship between dietary protein binding to cell membrane and intracellular calcium responses were examined in the CCK-producing enteroendocrine cell line STC-1. The binding of solubilized STC-1 cell membrane to proteins was analyzed using a surface plasmon resonance sensor. Intracellular calcium concentrations of STC-1 cell suspensions loaded with Fura-2 AM were measured using a spectrafluorophotometer system with continuous stirring. Intracellular calcium concentrations in STC-1 cells were increased by exposure to α-casein or casein sodium, but not to bovine serum albumin. Solubilized STC-1 membranes bound to α-casein and casein sodium but did not bind to bovine serum albumin. α-Casein demonstrated higher membrane binding and intracellular calcium stimulating activities than casein sodium. Thus, protein binding to the STC-1 cell membrane and intracellular calcium responses were correlated. Intracellular calcium responses to α-casein were suppressed by an L-type calcium channel blocker. These results suggest that casein, a dietary protein, binds to a putative receptor on the CCK-producing enteroendocrine cell membrane and elicits the subsequent intracellular calcium response via an L-type calcium channel.

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Vigont, V. A., O. A. Zimina, L. N. Glushankova, J. A. Kolobkova, M. A. Ryazantseva, G. N. Mozhayeva et E. V. Kaznacheyeva. « STIM1 Protein Activates Store-Operated Calcium Channels in Cellular Model of Huntington’s Disease ». Acta Naturae 6, n^o 4 (15 décembre 2014) : 40–47. http://dx.doi.org/10.32607/20758251-2014-6-4-40-47.

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We have shown that the expression of full-length mutated huntingtin in human neuroblastoma cells (SK-N-SH) leads to an abnormal increase in calcium entry through store-operated channels. In this paper, the expression of the N-terminal fragment of mutated huntingtin (Htt138Q-1exon) is shown to be enough to provide an actual model for Huntingtons disease. We have shown that Htt138Q-1exon expression causes increased store-operated calcium entry, which is mediated by at least two types of channels in SK-N-SH cells with different reversal potentials. Calcium sensor, STIM1, is required for activation of store-operated calcium entry in these cells. The results provide grounds for considering the proteins responsible for the activation and maintenance of the store-operated calcium entry as promising targets for developing novel therapeutics for neurodegenerative diseases.

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Nanou, Evanthia, Jane M. Sullivan, Todd Scheuer et William A. Catterall. « Calcium sensor regulation of the CaV2.1 Ca2+ channel contributes to short-term synaptic plasticity in hippocampal neurons ». Proceedings of the National Academy of Sciences 113, n^o 4 (11 janvier 2016) : 1062–67. http://dx.doi.org/10.1073/pnas.1524636113.

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Short-term synaptic plasticity is induced by calcium (Ca2+) accumulating in presynaptic nerve terminals during repetitive action potentials. Regulation of voltage-gated CaV2.1 Ca2+ channels by Ca2+ sensor proteins induces facilitation of Ca2+ currents and synaptic facilitation in cultured neurons expressing exogenous CaV2.1 channels. However, it is unknown whether this mechanism contributes to facilitation in native synapses. We introduced the IM-AA mutation into the IQ-like motif (IM) of the Ca2+ sensor binding site. This mutation does not alter voltage dependence or kinetics of CaV2.1 currents, or frequency or amplitude of spontaneous miniature excitatory postsynaptic currents (mEPSCs); however, synaptic facilitation is completely blocked in excitatory glutamatergic synapses in hippocampal autaptic cultures. In acutely prepared hippocampal slices, frequency and amplitude of mEPSCs and amplitudes of evoked EPSCs are unaltered. In contrast, short-term synaptic facilitation in response to paired stimuli is reduced by ∼50%. In the presence of EGTA-AM to prevent global increases in free Ca2+, the IM-AA mutation completely blocks short-term synaptic facilitation, indicating that synaptic facilitation by brief, local increases in Ca2+ is dependent upon regulation of CaV2.1 channels by Ca2+ sensor proteins. In response to trains of action potentials, synaptic facilitation is reduced in IM-AA synapses in initial stimuli, consistent with results of paired-pulse experiments; however, synaptic depression is also delayed, resulting in sustained increases in amplitudes of later EPSCs during trains of 10 stimuli at 10–20 Hz. Evidently, regulation of CaV2.1 channels by CaS proteins is required for normal short-term plasticity and normal encoding of information in native hippocampal synapses.

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