Cell calciumPub Date : 2023-11-10DOI: 10.1016/j.ceca.2023.102823
Jan B. Parys, Fernanda O. Lemos
{"title":"The interplay between associated proteins, redox state and Ca2+ in the intraluminal ER compartment regulates the IP3 receptor","authors":"Jan B. Parys, Fernanda O. Lemos","doi":"10.1016/j.ceca.2023.102823","DOIUrl":"https://doi.org/10.1016/j.ceca.2023.102823","url":null,"abstract":"<div><p>There have been in the last three decades repeated publications indicating that the inositol 1,4,5-trisphosphate receptor (IP<sub>3</sub>R) is regulated not only by cytosolic Ca<sup>2+</sup> but also by intraluminal Ca<sup>2+</sup>. Although most studies indicated that a decreasing intraluminal Ca<sup>2+</sup> level led to an inhibition of the IP<sub>3</sub>R, a number of publications reported exactly the opposite effect, i.e. an inhibition of the IP<sub>3</sub>R by high intraluminal Ca<sup>2+</sup> levels. Although intraluminal Ca<sup>2+</sup>-binding sites on the IP<sub>3</sub>Rs were reported, a regulatory role for them was not demonstrated. It is also well known that the IP<sub>3</sub>R is regulated by a vast array of associated proteins, but only relatively recently proteins were identified that can be linked to the regulation of the IP<sub>3</sub>R by intraluminal Ca<sup>2+</sup>. The first to be reported was annexin A1 that is proposed to associate with the second intraluminal loop of the IP<sub>3</sub>R at high intraluminal Ca<sup>2+</sup> levels and to inhibit the IP<sub>3</sub>R. More recently, ERdj5/PDIA19 reductase was described to reduce an intraluminal disulfide bridge of IP<sub>3</sub>R1 only at low intraluminal Ca<sup>2+</sup> levels and thereby to inhibit the IP<sub>3</sub>R. Annexin A1 and ERdj5/PDIA19 can therefore explain most of the experimental results on the regulation of the IP<sub>3</sub>R by intraluminal Ca<sup>2+</sup>. Further studies are needed to provide a fuller understanding of the regulation of the IP<sub>3</sub>R from the intraluminal side. These findings underscore the importance of the state of the endoplasmic reticulum in the control of IP<sub>3</sub>R activity.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134688843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-11-08DOI: 10.1016/j.ceca.2023.102819
Alba Delrio-lorenzo , Jonathan Rojo-ruiz, Patricia Torres-vidal, Maria Teresa Alonso, Javier García-sancho
{"title":"In vitro and in vivo calibration of low affinity genetic Ca2+ indicators","authors":"Alba Delrio-lorenzo , Jonathan Rojo-ruiz, Patricia Torres-vidal, Maria Teresa Alonso, Javier García-sancho","doi":"10.1016/j.ceca.2023.102819","DOIUrl":"10.1016/j.ceca.2023.102819","url":null,"abstract":"<div><p>Calcium is a universal intracellular messenger and proper Ca<sup>2+</sup>concentrations ([C<em>a</em><sup>2+</sup>]) both in the cytosol and in the lumen of cytoplasmic organelles are essential for cell functions. Ca<sup>2+</sup> homeostasis is achieved by a delicate pump/leak balance both at the plasma membrane and at the endomembranes, and improper Ca<sup>2+</sup> levels result in malfunction and disease. Selective intraorganellar Ca<sup>2+</sup>measurements are best achieved by using targeted genetically encoded Ca<sup>2+</sup> indicators (GECIs) but to calibrate the luminal fluorescent signals into accurate [Ca<sup>2+</sup>] is challenging, especially <em>in vivo</em>, due to the difficulty to normalize and calibrate the fluorescent signal in various tissues or conditions. We report here a procedure to calibrate the ratiometric signal of GAP (GFP-Aequorin Protein) targeted to the endo-sarcoplasmic reticulum (ER/SR) into [Ca<sup>2+</sup>]<sub>ER/SR</sub> based on imaging of fluorescence after heating the tissue at 50–52 °C, since this value coincides with that obtained in the absence of Ca<sup>2+</sup> (R<sub>min</sub>). Knowledge of the dynamic range (R<sub>max</sub>/R<sub>min</sub>) and the Ca<sup>2+</sup>-affinity (K<sub>D</sub>) of the indicator permits calculation of [Ca<sup>2+</sup>] by applying a simple algorithm. We have validated this procedure <em>in vitro</em> using several cell types (HeLa, HEK 293T and mouse astrocytes), as well as <em>in vivo</em> in <em>Drosophila</em>. Moreover, this methodology is applicable to other low Ca<sup>2+</sup> affinity green and red GECIs.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92152718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-11-08DOI: 10.1016/j.ceca.2023.102822
Guangli Guo , Lu Wang , Xiaowei Li , Wanrong Fu , Jinhua Cao , Jianchao Zhang , Yangyang Liu , Mengduan Liu , Mengyu Wang , Guojun Zhao , Xi Zhao , Yangfan Zhou , Shaohui Niu , Gangqiong Liu , Yanzhou Zhang , Jianzeng Dong , Hailong Tao , Xiaoyan Zhao
{"title":"Enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction in patient-specific induced pluripotent stem cell-derived cardiomyocytes with MYH7 mutation","authors":"Guangli Guo , Lu Wang , Xiaowei Li , Wanrong Fu , Jinhua Cao , Jianchao Zhang , Yangyang Liu , Mengduan Liu , Mengyu Wang , Guojun Zhao , Xi Zhao , Yangfan Zhou , Shaohui Niu , Gangqiong Liu , Yanzhou Zhang , Jianzeng Dong , Hailong Tao , Xiaoyan Zhao","doi":"10.1016/j.ceca.2023.102822","DOIUrl":"10.1016/j.ceca.2023.102822","url":null,"abstract":"<div><p>Hypertrophic cardiomyopathy (HCM), the most common inherited heart disease, is frequently caused by mutations in the β-cardiac myosin heavy chain gene (<em>MYH7</em>). Abnormal calcium handling and diastolic dysfunction are archetypical features of HCM caused by <em>MYH7</em> gene mutations. However, the mechanism of how MYH7 mutations leads to these features remains unclear, which inhibits the development of effective therapies. Initially, cardiomyocytes were generated from induced pluripotent stem cells from an eight-year-old girl diagnosed with HCM carrying a <em>MYH7</em>(C.1063 <em>G</em>><em>A</em>) heterozygous mutation(mutant-iPSC-CMs) and mutation-corrected isogenic iPSCs(control-iPSC-CMs) in the present study. Next, we compared phenotype of mutant-iPSC-CMs to that of control-iPSC-CMs, by assessing their morphology, hypertrophy-related genes expression, calcium handling, diastolic function and myofilament calcium sensitivity at days 15 and 40 respectively. Finally, to better understand increased myofilament Ca<sup>2+</sup> sensitivity as a central mechanism of central pathogenicity in HCM, inhibition of calcium sensitivity with mavacamten can improveed cardiomyocyte hypertrophy. Mutant-iPSC-CMs exhibited enlarged areas, increased sarcomere disarray, enhanced expression of hypertrophy-related genes proteins, abnormal calcium handling, diastolic dysfunction and increased myofilament calcium sensitivity at day 40, but only significant increase in calcium sensitivity and mild diastolic dysfunction at day 15. Increased calcium sensitivity by levosimendan aggravates cardiomyocyte hypertrophy phenotypes such as expression of hypertrophy-related genes, abnormal calcium handling and diastolic dysfunction, while inhibition of calcium sensitivity significantly improves cardiomyocyte hypertrophy phenotypes in mutant-iPSC-CMs, suggesting increased myofilament calcium sensitivity is the primary mechanisms for <em>MYH7</em> mutations pathogenesis. Our studies have uncovered a pathogenic mechanism of HCM caused by <em>MYH7</em> gene mutations through which enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction. Correction of the myofilament calcium sensitivity was found to be an effective method for treating the development of HCM phenotype <em>in vitro.</em></p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0143416023001331/pdfft?md5=d6cc6dca2cba78e93c981fb221e8889e&pid=1-s2.0-S0143416023001331-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135515040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Transcriptional, biochemical, and immunohistochemical analyses of CaMKKβ/2 splice variants that co-localize with CaMKIV in spermatids","authors":"Satomi Ohtsuka , Yumi Miyai , Hiroyuki Mima , Masaki Magari , Yoichi Chiba , Futoshi Suizu , Hiroyuki Sakagami , Masaki Ueno , Hiroshi Tokumitsu","doi":"10.1016/j.ceca.2023.102820","DOIUrl":"https://doi.org/10.1016/j.ceca.2023.102820","url":null,"abstract":"<div><p>Ca<sup>2+</sup>/calmodulin-dependent protein kinase kinase (CaMKK) phosphorylates and activates downstream protein kinases, including CaMKI, CaMKIV, PKB/Akt, and AMPK; thus, regulates various Ca<sup>2+</sup>-dependent physiological and pathophysiological pathways. Further, CaMKKβ/2 in mammalian species comprises multiple alternatively spliced variants; however, their functional differences or redundancy remain unclear. In this study, we aimed to characterize mouse CaMKKβ/2 splice variants (CaMKKβ-3 and β-3x). RT-PCR analyses revealed that mouse <em>CaMKKβ-1</em>, consisting of 17 exons, was predominantly expressed in the brain; whereas, mouse <em>CaMKKβ-3</em> and <em>β-3x</em>, lacking exon 16 and exons 14/16, respectively, were primarily expressed in peripheral tissues. At the protein level, the CaMKKβ-3 or β-3x variants showed high expression levels in mouse cerebrum and testes. This was consistent with the localization of CaMKKβ-3/-3x in spermatids in seminiferous tubules, but not the localization of CaMKKβ-1. We also observed the co-localization of CaMKKβ-3/-3x with a target kinase, CaMKIV, in elongating spermatids. Biochemical characterization further revealed that CaMKKβ-3 exhibited Ca<sup>2+</sup>/CaM-induced kinase activity similar to CaMKKβ-1. Conversely, we noted that CaMKKβ-3x impaired Ca<sup>2+</sup>/CaM-binding ability, but exhibited significantly weak autonomous activity (approximately 500-fold lower than CaMKKβ-1 or β-3) due to the absence of C-terminal of the catalytic domain and a putative residue (Ile478) responsible for the kinase autoinhibition. Nevertheless, CaMKKβ-3x showed the ability to phosphorylate downstream kinases, including CaMKIα, CaMKIV, and AMPKα in transfected cells comparable to CaMKKβ-1 and β-3. Collectively, CaMKKβ-3/-3x were identified as functionally active and could be <em>bona fide</em> CaMKIV-kinases in testes involved in the activation of the CaMKIV cascade in spermatids, resulting in the regulation of spermiogenesis.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134688844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-11-04DOI: 10.1016/j.ceca.2023.102821
Rodrigo Torres , Cecilia Hidalgo
{"title":"Subcellular localization and transcriptional regulation of brain ryanodine receptors. Functional implications","authors":"Rodrigo Torres , Cecilia Hidalgo","doi":"10.1016/j.ceca.2023.102821","DOIUrl":"10.1016/j.ceca.2023.102821","url":null,"abstract":"<div><p>Ryanodine receptors (RyR) are intracellular Ca<sup>2+</sup> channels localized in the endoplasmic reticulum, where they act as critical mediators of Ca<sup>2+</sup>-induced Ca<sup>2+</sup> calcium release (CICR). In the brain, mammals express in both neurons, and non-neuronal cells, a combination of the three RyR-isoforms (RyR1–3). Pharmacological approaches, which do not distinguish between isoforms, have indicated that RyR-isoforms contribute to brain function. However, isoform-specific manipulations have revealed that RyR-isoforms display different subcellular localizations and are differentially associated with neuronal function. These findings raise the need to understand RyR-isoform specific transcriptional regulation, as this knowledge will help to elucidate the causes of neuronal dysfunction for a growing list of brain disorders that show altered RyR channel expression and function.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72215729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-11-04DOI: 10.1016/j.ceca.2023.102817
Christine R. Rose , Alexej Verkhratsky
{"title":"Sodium homeostasis and signalling: The core and the hub of astrocyte function","authors":"Christine R. Rose , Alexej Verkhratsky","doi":"10.1016/j.ceca.2023.102817","DOIUrl":"https://doi.org/10.1016/j.ceca.2023.102817","url":null,"abstract":"<div><p><span>Neuronal activity and neurochemical stimulation trigger spatio-temporal changes in the cytoplasmic concentration of Na</span><sup>+</sup> ions in astrocytes. These changes constitute the substrate for Na<sup>+</sup> signalling and are fundamental for astrocytic excitability. Astrocytic Na<sup>+</sup> signals are generated by Na<sup>+</sup><span><span> influx through neurotransmitter transporters, with primary contribution of </span>glutamate transporters, and through cationic channels; whereas recovery from Na</span><sup>+</sup> transients is mediated mainly by the plasmalemmal Na<sup>+</sup>/K<sup>+</sup><span> ATPase. Astrocytic Na</span><sup>+</sup> signals regulate the activity of plasmalemmal transporters critical for homeostatic function of astrocytes, thus providing real-time coordination between neuronal activity and astrocytic support.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134688845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-10-24DOI: 10.1016/j.ceca.2023.102818
Daniel Khananshvili
{"title":"Neuronal and astrocyte NCX isoform/splice variants: How do they participate in Na+ and Ca2+ signalling?","authors":"Daniel Khananshvili","doi":"10.1016/j.ceca.2023.102818","DOIUrl":"https://doi.org/10.1016/j.ceca.2023.102818","url":null,"abstract":"<div><p>NCX1, NCX2, and NCX3 gene isoforms and their splice variants are characteristically expressed in different regions of the brain. The tissue-specific splice variants of NCX1–3 isoforms show specific expression profiles in neurons and astrocytes, whereas the relevant NCX isoform/splice variants exhibit diverse allosteric modes of Na<sup>+</sup>- and Ca<sup>2+</sup>-dependent regulation. In general, overexpression of NCX1–3 genes leads to neuroprotective effects, whereas their ablation gains the opposite results. At this end, the partial contributions of NCX isoform/splice variants to neuroprotective effects remain unresolved. The glutamate-dependent Na<sup>+</sup> entry generates Na<sup>+</sup> transients (in response to neuronal cell activities), whereas the Na<sup>+</sup>-driven Ca<sup>2+</sup> entry (through the reverse NCX mode) raises Ca<sup>2+</sup> transients. This special mode of signal coupling translates Na<sup>+</sup> transients into the Ca<sup>2+</sup> signals while being a part of synaptic neurotransmission. This mechanism is of general interest since disease-related conditions (ischemia, metabolic stress, and stroke among many others) trigger Na<sup>+</sup> and Ca<sup>2+</sup> overload with deadly outcomes of downstream apoptosis and excitotoxicity. The recently discovered mechanisms of NCX allosteric regulation indicate that some NCX variants might play a critical role in the dynamic coupling of Na<sup>+</sup>-driven Ca<sup>2+</sup> entry. In contrast, the others are less important or even could be dangerous under altered conditions (e.g., metabolic stress). This working hypothesis can be tested by applying advanced experimental approaches and highly focused computational simulations. This may allow the development of structure-based blockers/activators that can selectively modulate predefined NCX variants to lessen the life-threatening outcomes of excitotoxicity, ischemia, apoptosis, metabolic deprivation, brain injury, and stroke.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92135821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-10-18DOI: 10.1016/j.ceca.2023.102815
Francesco Moccia , Anthony J. Morgan
{"title":"TPC2 gating: Trying to break the enigma code","authors":"Francesco Moccia , Anthony J. Morgan","doi":"10.1016/j.ceca.2023.102815","DOIUrl":"https://doi.org/10.1016/j.ceca.2023.102815","url":null,"abstract":"","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92043987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-10-18DOI: 10.1016/j.ceca.2023.102816
Jasmin Baron, Klaus Groschner, Oleksandra Tiapko
{"title":"Calcium transport and sensing in TRPC channels – New insights into a complex feedback regulation","authors":"Jasmin Baron, Klaus Groschner, Oleksandra Tiapko","doi":"10.1016/j.ceca.2023.102816","DOIUrl":"10.1016/j.ceca.2023.102816","url":null,"abstract":"<div><p>Canonical TRP (TRPC) channels are a still enigmatic family of signaling molecules with multimodal sensing features. These channels enable Ca<sup>2+</sup> influx through the plasma membrane to control a diverse range of cellular functions. Based on both regulatory- and recently uncovered structural features, TRPC channels are considered to coordinate Ca<sup>2+</sup> and other divalent cations not only within the permeation path but also at additional sensory sites. Analysis of TRPC structures by cryo-EM identified multiple regulatory ion binding pockets. With this review, we aim at an overview and a critical discussion of the current concepts of divalent sensing by TRPC channels.</p></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66783616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cell calciumPub Date : 2023-10-05DOI: 10.1016/j.ceca.2023.102813
Daniela Anderson , A.J. Robison
{"title":"Commentary: Untangling the structural and enzymatic roles of CaMKII at the synapse","authors":"Daniela Anderson , A.J. Robison","doi":"10.1016/j.ceca.2023.102813","DOIUrl":"10.1016/j.ceca.2023.102813","url":null,"abstract":"","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41115275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}