Cell calcium最新文献

{"title":"Connexin 43 as a novel Ca2+ transport pathway in the nuclear envelope of human induced pluripotent stem cell derived cardiomyocytes","authors":"Noemi Toth ,&nbsp;Nordine Helassa ,&nbsp;Martin Morad","doi":"10.1016/j.ceca.2025.103090","DOIUrl":"10.1016/j.ceca.2025.103090","url":null,"abstract":"<div><div>Nuclear envelope (NE) is a double lipid bilayer separating the nucleus from the cytosol. While cytoplasmic and sarcoplasmic reticulum (SR) Ca²⁺ signaling is extensively studied, the role of NE in cellular Ca²⁺ dynamics and the identity and regulation of nuclear Ca²⁺ transporters remain less explored.</div><div>NE-associated Ca²⁺ activity was examined using a genetically engineered fluorescent Ca²⁺ probe targeting nuclear LaminB1 at the inner NE membrane in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC<img>CMs). Confocal imaging of NE revealed larger and delayed but slower rise of Ca²⁺ in the nuclear lamina compared to I_C_a triggered cytosolic rise in Ca²⁺. Caffeine induced ∼4X larger Ca²⁺rise in NE lamina compared to I_C_a. To determine whether NE Ca²⁺ signaling depended on SR Ca²⁺ release, we measured the nuclear Ca²⁺signals of cells expressing genetically CICR-impaired RyR2 mutations (E3848A, Q3925E), where SR Ca²⁺ release was fully suppressed. In these CICR-deleted cells, although caffeine failed to activate robust NE Ca²⁺ transients, spontaneous beating persisted activating NE Ca²⁺ transients, suggesting Ca²⁺ signaling pathway remodeling and activation of an alternate Ca²⁺ pathway. Confocal imaging of hiPSC<img>CMs infected with antibodies to Cx43 identified robust Cx43 expression in the NE, the inhibition of which by Gap19 protein blocked the rise of nuclear lamina Ca²⁺-transients. We conclude, that while SR Ca²⁺ release is essential in replenishing the NE Ca²⁺ content, RyR2 mutations that delete CICR induce remodeling of Ca²⁺signaling pathway that may include Cx43 to maintain Ca²⁺ fluxes critical for spontaneous beating and triggering of Ca²⁺transients.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103090"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145573271","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}

{"title":"SERCA3, ubiquitous but specific calcium pumps?","authors":"Maëliss Toth ,&nbsp;Shaymaa Alhabib ,&nbsp;Boris Manoury ,&nbsp;Régis Bobe ,&nbsp;Véronique Leblais","doi":"10.1016/j.ceca.2025.103079","DOIUrl":"10.1016/j.ceca.2025.103079","url":null,"abstract":"<div><div>The calcium ion (Ca²⁺) is an important second messenger for the organism, participating in the regulation of various physiological responses in all cell types. In view of its crucial role, maintaining calcium homeostasis is important. This is why many players tightly regulate calcium homeostasis. These include a type of transporter historically located in the sarcoplasmic or endoplasmic reticulum (SR or ER), called Sarco-Endoplasmic Reticulum Ca²⁺-ATPase or SERCA calcium pumps (Toyoshima et al., 2000). Existence of these pumps was first demonstrated in the 1960s in rabbit skeletal muscle (Ebashi and Lipmann, 1962). In the mid-80s, only two families of these transporters, SERCA1 and SERCA2, were described in the skeletal muscle and the cardiovascular system, respectively. However, the existence of a third family, named SERCA3, was subsequently revealed. In this review, we present an overview of the current knowledge of the SERCA3. We firstly present the structure of this pump from its gene to the protein and its catalytic properties, highlighting its specific features compared to other isoforms. We then focus on the pathophysiological settings by describing its functional role established in several organs and pointing out the studies assuming its implication in different diseases such as obesity or cancers.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103079"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145079624","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}

{"title":"Neuronal regulation of myenteric interstitial cells of Cajal (ICC-MY) in the proximal colon","authors":"Salah A. Baker ,&nbsp;Bernard T. Drumm ,&nbsp;Manushri Karwa ,&nbsp;Katy M. Thompson ,&nbsp;Benjamin Smith ,&nbsp;Kenton M. Sanders","doi":"10.1016/j.ceca.2025.103082","DOIUrl":"10.1016/j.ceca.2025.103082","url":null,"abstract":"<div><div>Interstitial cells of Cajal (ICC) generate contractile patterns of colonic motility. We investigated innervation of ICC within the plane of the myenteric plexus (ICC-MY) in proximal colon using mice expressing GCaMP6f in ICC. ICC-MY generated localized Ca²⁺ transients that couple to activation of ANO1 channels, a Ca²⁺-activated Cl^- conductance. ICC are electrically coupled to SMCs, so activation or suppression of currents in ICC affects excitability of SMCs. ICC-MY displayed tonic inhibition, as the neurotoxin, TTX, increased the frequency of Ca²⁺ transients. Tonic inhibition was mimicked by a nitric oxide donor, NONOate, and by a guanylate cyclase agonist (Bay 58–2667). In contrast ODQ mimicked effects of TTX, increasing Ca²⁺ transients. Carbachol (CCh) increased Ca²⁺ transients in ICC-MY, and these effects were mediated by M3 muscarinic receptors. Neostigmine, also increased Ca²⁺ transients, suggesting there is tonic activation of enteric excitatory neurons in colonic muscles. Substance P and antagonists of NK1 and NK2 receptors had no effect on Ca²⁺ transients in ICC-MY. Electrical field stimulation (EFS), under conditions that emphasized excitatory neural responses, enhanced Ca²⁺ transients, and these effects were blocked by atropine or an M3 receptor antagonist (DAU 5884). EFS in the presence of atropine caused inhibition of Ca²⁺ via release of NO. Cessation of nitrergic stimulation resulted in a substantial increase in Ca²⁺ transients, known as post-stimulus excitation. In summary, ICC-MY, important for the generation of propulsive contractions in the colon, are innervated by excitatory (cholinergic) and inhibitory (nitrergic) motor neurons, and these inputs regulate the excitability of these cells.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103082"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154986","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}

{"title":"MICU1 attenuates neuronal apoptosis after subarachnoid hemorrhage by inhibiting mitochondrial calcium overload and damage","authors":"Jie Wang ,&nbsp;Yue Cui ,&nbsp;Peng-Fei Ding ,&nbsp;Jia-Tong Zhang ,&nbsp;Xun-Zhi Liu ,&nbsp;Sen Gao ,&nbsp;Xiang-Xin Chen ,&nbsp;Zheng Peng ,&nbsp;Xiao-Jian Li ,&nbsp;Ling-Yun Wu ,&nbsp;Yong-Yue Gao ,&nbsp;Chun-Hua Hang ,&nbsp;Wei Li","doi":"10.1016/j.ceca.2025.103080","DOIUrl":"10.1016/j.ceca.2025.103080","url":null,"abstract":"<div><h3>Background</h3><div>Subarachnoid hemorrhage (SAH) is a severe neurological emergency associated with substantial morbidity and mortality. Research into the mechanisms underlying neuronal injury following SAH has identified early brain injury (EBI) as a critical factor influencing clinical outcomes. Among the various pathological processes involved in EBI, calcium overload remains relatively understudied yet plays a pivotal role in neuronal damage. Excessive accumulation of calcium within mitochondria can initiate apoptotic and autophagic pathways, contributing to cell death. Mitochondrial calcium uptake 1 (MICU1), a regulatory protein located on the inner mitochondrial membrane, functions to modulate mitochondrial calcium ions by inhibiting calcium influx under conditions of low intracellular calcium concentration.</div></div><div><h3>Methods</h3><div>Mitochondria were extracted from the cerebrospinal fluid (CSF) of patients with SAH to evaluate the extent of mitochondrial damage. In vivo and in vitro SAH models were employed to assess mitochondrial damage and dynamic changes in both mitochondrial and cytosolic calcium levels. The interaction between MICU1 and mitochondria was further examined. To investigate the functional role of MICU1, lentivirus vectors were used to upregulate MICU1 expression, while siRNA was applied to knock down its expression in Neuron-2a (N2a) cells. Following hemoglobin (Hb) stimulation, mitochondrial damage and apoptosis were systematically evaluated.</div></div><div><h3>Results</h3><div>Analysis of CSF from SAH patients revealed decreased MICU1 expression and aggravated mitochondrial damage. Hb stimulation of primary neurons and N2a cells led to reduced MICU1 expression and mitochondrial calcium overload, which mediated mitochondrial damage and promoted the progression of neuronal apoptosis. Following upregulation of MICU1 expression in N2a cells, the cells exhibited enhanced tolerance to Hb-induced calcium overload, resulting in a significant reduction in mitochondrial damage. This protective effect was attenuated by MICU1 siRNA treatment. Moreover, MICU1 overexpression alleviated Hb-induced apoptosis in N2a cells, whereas siRNA-mediated knockdown of MICU1 exacerbated apoptotic responses.</div></div><div><h3>Conclusion</h3><div>Mitochondrial calcium overload in neurons following SAH contributes to the development of EBI and neuronal damage. MICU1 exerts a neuroprotective role by mitigating mitochondrial calcium overload, thereby reducing mitochondrial damage and neuronal apoptosis.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103080"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102587","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}

{"title":"Silencing CALB1 enhances prostate cancer radiosensitivity via calcium-mediated mitochondrial dysfunction and cellular senescence","authors":"Chen Gong ,&nbsp;Senmao Li ,&nbsp;Ye An ,&nbsp;Chadanfeng Yang ,&nbsp;Zhiyong Tan ,&nbsp;Wujie Chen ,&nbsp;Dihao Lv ,&nbsp;Haichao Wu ,&nbsp;Haifeng Wang ,&nbsp;Shi Fu ,&nbsp;Haihao Li ,&nbsp;Yanjie Kong ,&nbsp;Yinglong Huang ,&nbsp;Mingxia Ding","doi":"10.1016/j.ceca.2025.103071","DOIUrl":"10.1016/j.ceca.2025.103071","url":null,"abstract":"<div><h3>Background</h3><div>Prostate cancer remains a leading cause of cancer-related deaths in men, with radioresistance limiting treatment efficacy. This study investigates the role of Calbindin 1 (CALB1), a calcium-binding protein regulated by miR-186–5p, in prostate cancer progression and radiation response.</div></div><div><h3>Methods</h3><div>CALB1 expression was analyzed using GEO and TCGA datasets, and the regulatory relationship with miR-186–5p was validated. Functional studies including CALB1 knockdown, calcium chelation, and mitochondrial rescue interventions were conducted in prostate cancer cells, spheroids, and xenograft models, assessing proliferation, senescence, calcium homeostasis, and radiation response.</div></div><div><h3>Results</h3><div>We identified CALB1 as a target of downregulated miR-186–5p in prostate cancer. CALB1 silencing inhibited prostate cancer growth by inducing cellular senescence through calcium dysregulation, mitochondrial dysfunction, and oxidative stress. CALB1 depletion significantly enhanced radiosensitivity both in vitro and in vivo, with calcium chelation or mitochondrial interventions partially rescuing these effects.</div></div><div><h3>Conclusions</h3><div>CALB1 regulates prostate cancer progression and radiation response by maintaining calcium homeostasis. Its depletion triggers calcium overload and mitochondrial dysfunction, enhancing radiation sensitivity and identifying CALB1 as a potential therapeutic target.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103071"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144926570","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}

{"title":"Pathological calcium influx through amyloid beta pores disrupts synaptic function","authors":"Temitope Adeoye,&nbsp;Ghanim Ullah","doi":"10.1016/j.ceca.2025.103083","DOIUrl":"10.1016/j.ceca.2025.103083","url":null,"abstract":"<div><div>Alzheimer's disease (AD) is characterized by profound disruption of synaptic function, with mounting evidence suggesting that amyloid-β (Aβ) oligomers disrupt calcium (Ca²⁺) homeostasis through membrane pore formation. While these pores are known to alter intracellular Ca²⁺ dynamics, their immediate impact on synaptic transmission and potential interaction with Familial AD (FAD)-associated endoplasmic reticulum (ER) dysfunction remains unclear. Here, we extend our previously developed model of presynaptic Ca²⁺ dynamics to examine how Aβ pores alter exocytosis and how such disruptions may manifest in the presence of FAD-associated ER dysfunction. Our model reveals that Aβ pores fundamentally alter both the timing and strength of neurotransmitter release. Unexpectedly, the impact of pores on synaptic function depends critically on their pattern of activity, where continuous pore activity leads to synaptic hyperactivation, while brief periods of intense pore activity trigger lasting hypoactivation at short timescales. These effects manifest most strongly in synapses with low and intermediate release probabilities, highlighting the established selective vulnerability of such synaptic configurations. We find that Aβ pores and FAD-driven ER Ca²⁺ dysregulation form an integrated pathological unit through bidirectional coupling of their respective Ca²⁺ microdomains to create complex patterns of disruptions. This coupling creates a feedback loop that produces an additive effect on neurotransmitter release during brief stimulations, but non-additive effects during sustained activity that promotes a shift towards asynchronous release. Surprisingly, our simulations predict that extended pore activity does not worsen indefinitely but only produces a modest additional disruption beyond initial pore formation that is likely determined by the intrinsic properties of the synapse. These findings indicate that early synaptic dysfunction in AD may arise from subtle perturbations in the temporal coordination of release rather than gross Ca²⁺ dysregulation, providing new mechanistic insights into the progressive nature of Aβ-driven synaptic failure in AD.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103083"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217036","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}

{"title":"CPVT1 point mutations in RyR2 S5 and S6 segments and their Ca2+ signaling consequence","authors":"Xiao-hua Zhang ,&nbsp;Grace Ellen Donch ,&nbsp;Naohiro Yamaguchi ,&nbsp;Martin Morad","doi":"10.1016/j.ceca.2025.103081","DOIUrl":"10.1016/j.ceca.2025.103081","url":null,"abstract":"<div><div>Precise activation of cardiac ryanodine receptor (RyR2) by small influx of Ca²⁺ during the action potential triggers the release of SR Ca²⁺ that activates contraction, a process known as Ca²⁺-induced Ca²⁺ release (CICR). Missense mutations in RyR2 often cause aberrant and unregulated Ca²⁺ releases that are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), often lethal arrhythmias. Here using CRISPR/Cas9 gene editing in human induced pluripotent stem cells (hiPSCs), we extended our previous studies to include two new arrhythmogenic mutations one, R4822H, located in S5-S6 transmembrane luminal loop near RyR2 selective filter and the other, L4865V, located on S6 segment. TIRF-imaging of voltage-clamped mutant myocytes showed that I_Ca and caffeine-triggered cytosolic Ca²⁺ rise (Fura-2 signal) or ER-GCaMP6 SR Ca²⁺ release signals were significantly suppressed in R4822H but not in L4865V myocytes. Spontaneous Ca²⁺ transients, however, persisted in both mutant lines activating both Fura-2 and ER-GCaMP6 Ca²⁺ transients in L4865V cells, but only Fura-2 Ca²⁺ transients in R4822H mutant. Spontaneous Ca²⁺ sparks igniting frequencies were similar in both mutants, but spark durations were significantly shorter. Although both of these mutations are located at S5 and S6 transmembrane regions of RyR2, their phenotypes diverge markedly. L4865V mutant does not show suppressed E-C coupling function, while R4822H mutant has completely suppressed CICR suggesting that the spontaneous beating in R4822H mutant results from remodeling of dormant Ca²⁺ signaling pathway expressed in hiPSC<img>CMs.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"132 ","pages":"Article 103081"},"PeriodicalIF":4.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102592","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}

{"title":"Chemical but not mechanical stimulation reduce TRPA1 channel lateral mobility","authors":"Alicia Sampieri ,&nbsp;Alexander Asanov ,&nbsp;Aaron Pavel Rodríguez-Hernández ,&nbsp;Ileana Tobías-Juárez ,&nbsp;Daniel Martínez-Flores ,&nbsp;Luis Vaca","doi":"10.1016/j.ceca.2025.103059","DOIUrl":"10.1016/j.ceca.2025.103059","url":null,"abstract":"<div><div>The transient Receptor Potential Ankyrin 1 (TRPA1) is a member from the TRP superfamily of ion channels. TRPA1 channels are calcium-permeable nonselective cation channels, which are highly conserved throughout the animal kingdom. Mammals have only one member (TRPA1), while zebrafish has two (TRPA1a and TRPA1b). TRPA1 channels are activated by a plethora of stimuli, including noxious cold, mechanical stimulation, calcium, pH, reactive oxygen, and carbonyl species. In the present study we characterize the modulation of TRPA1b channel lateral mobility by Allyl isothiocyanate (AITC) and mechanical stimulation. We show that only AITC stimulation alters channel diffusion at the plasma membrane.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"131 ","pages":"Article 103059"},"PeriodicalIF":4.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772087","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}

{"title":"Calmodulin enhancement of mitochondrial calcium uniporter function in isolated mitochondria","authors":"Sara A. Garcia ,&nbsp;Anne M. Neumaier ,&nbsp;Michael Kohlhaas ,&nbsp;Anton Xu ,&nbsp;Alexander Nickel ,&nbsp;Katharina J. Ermer ,&nbsp;Luzia Enzner ,&nbsp;Christoph Maack ,&nbsp;Vasco Sequeira ,&nbsp;Christopher N. Johnson","doi":"10.1016/j.ceca.2025.103056","DOIUrl":"10.1016/j.ceca.2025.103056","url":null,"abstract":"<div><div>Mitochondrial calcium (Ca²⁺) uptake and factors that regulate this process have been an area of immense interest given the roles in cellular energetics. Here, we have investigated the ability of the Ca²⁺ sensing protein Calmodulin (CaM) to modify the function of the Mitochondrial Ca²⁺ Uniporter (MCU). Our data leveraged recombinantly produced CaM and mitochondria isolated from healthy and MCU impaired/diseased mice (Barth syndrome model). We found CaM enhanced Ca²⁺ uptake in both the absence and presence of CaMKII inhibition (KN93 as well as AIP). Mitochondria lacking function MCU (Barth syndrome model) validated that MCU was responsible for Ca²⁺ uptake in our experiments. Control experiments demonstrate that the observed CaM enhancement does not arise from CaM Ca²⁺ buffering. Fitting the Ca²⁺fluorescence data supported a monophasic decay process where the presence of CaM yielded enhanced kinetic rates of Ca²⁺ uptake. This CaM enhancement effect persisted in the presence of PTP impairment (cyclosporin), and subtle modification to the CaM protein sequence (D131E) revealed that an intact CaM-C domain Ca²⁺ binding was required for enhancement of MCU function.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"131 ","pages":"Article 103056"},"PeriodicalIF":4.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772086","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}

{"title":"Regulation of K+-dependent Na+/Ca2+-exchanger subtype 4, NCKX4, by palmitoylation","authors":"By Maryam Al-Khannaq ,&nbsp;Jonathan Lytton","doi":"10.1016/j.ceca.2025.103069","DOIUrl":"10.1016/j.ceca.2025.103069","url":null,"abstract":"<div><div>Mammalian K⁺-dependent Na⁺/Ca²⁺ exchangers (NCKX), encoded by the SLC24 gene family, are crucial for maintaining Ca²⁺ homeostasis. NCKX4, widely expressed in the brain and sensory neurons, plays a key role in neuronal satiety and enamel formation. Despite its importance, the regulatory mechanisms of NCKX4 remain largely unexplored. This study investigates how palmitoylation, a post-translational modification affecting membrane proteins, regulates NCKX4 and influences its cellular localization and function.</div><div>Using Acyl-RAC and palmitate-based click-chemistry, we found that approximately 14% of NCKX4 is palmitoylated at steady-state in both endogenous and transfected systems. The level of this modification is highly dynamic, being regulated by inhibitors of palmitoylation (2-bromopalmitate) and depalmitoylation (palmostatin B), resulting in greater than a two-fold decrease or increase, respectively. Site-directed mutagenesis of six cysteine residues revealed two key sites (Cys118 and Cys425) critical for NCKX4 palmitoylation.</div><div>The subcellular distribution of palmitoylated NCKX4 was examined via proximity ligation and click-chemistry. NCKX4 was found across multiple membrane compartments, with a higher fraction localizing to the plasma membrane when palmitoylation was inhibited by 2-bromopalmitate. However, a Ca²⁺ imaging assay in HEK293T cells showed no significant change in aggregate cellular NCKX4-mediated Ca²⁺ transport upon modulation of palmitoylation status. These data suggest palmitoylation promotes internalization of the NCKX4 protein while also activating it, counter-acting effects that result in unchanged NCKX4-mediated cellular Ca²⁺ transport activity.</div><div>In summary, NCKX4 is subject to dynamic palmitoylation, which influences both distribution across cellular compartments and intrinsic Ca²⁺ transport activity. These findings contribute to our understanding of the regulation and functional roles of NCKX4 in cellular physiology.</div></div>","PeriodicalId":9678,"journal":{"name":"Cell calcium","volume":"131 ","pages":"Article 103069"},"PeriodicalIF":4.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889882","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}