Ca2+ regulation
Dotaz
Zobrazit nápovědu
Phosphofurin acidic cluster sorting protein 2 (PACS2) plays a vital role in maintaining cellular homeostasis by regulating protein trafficking between cellular membranes. This function impacts crucial processes like apoptosis, mitochondria-endoplasmic reticulum interaction, and subsequently Ca2+ flux, lipid biosynthesis, and autophagy. Missense mutations, particularly E209K and E211K, are linked to developmental and epileptic encephalopathy-66 (DEE66), known as PACS2 syndrome. Individuals with this syndrome exhibit neurodevelopmental delay, seizures, facial dysmorphism, hypotonia, and delayed motor skills.Understanding the impact of these missense mutations on molecular processes is crucial. Studies suggest that E209K mutation decreases phosphorylation, increases the survival time of protein, and modifies protein-protein interaction, consequently leading to disruption of calcium flux and lower resistance to apoptosis induction. Unfortunately, to date, only a limited number of research groups have investigated the effects of mutations in the PACS2 gene. Current research on PACS2 syndrome is hampered by the lack of suitable models. While in vitro models using transfected cell lines offer insights, they cannot fully capture the disease's complexity.To address this, utilizing cells from individuals with PACS2 syndrome, specifically induced pluripotent stem cells (iPSCs), holds promise for understanding phenotypic diversity and developing personalized therapies. However, iPSC models may not fully capture tissue-specific effects of the E209K/E211K mutation. In vivo studies using animal models, particularly mice, could overcome these limitations.This review summarizes current knowledge about PACS2 structure and functions, explores the cellular consequences of E209K and E211K mutations, and highlights the potential of iPSC and mouse models in advancing our understanding of PACS2 syndrome.
OBJECTIVE: Transgenic mice with fluorescent protein (FP) reporters take full advantage of new in vivo imaging technologies. Therefore, we generated a TRPC5- and a TRPA1-reporter mouse based on FP C-terminal fusion, providing us with better alternatives for studying the physiology, interaction and coeffectors of these two TRP channels at the cellular and tissue level. METHODS: We generated transgenic constructs of the murine TRPC5- and TRPA1-gene with a 3*GGGGS linker and C-terminal fusion to mCherry and mTagBFP, respectively. We microinjected zygotes to generate reporter mice. Reporter mice were examined for visible fluorescence in trigeminal ganglia with two-photon microscopy, immunohistochemistry and calcium imaging. RESULTS: Both TRPC5-mCherry and TRPA1-mTagBFP knock-in mouse models were successful at the DNA and RNA level. However, at the protein level, TRPC5 resulted in no mCherry fluorescence. In contrast, sensory neurons derived from the TRPA1-reporter mice exhibited visible mTag-BFP fluorescence, although TRPA1 had apparently lost its ion channel function. CONCLUSIONS: Creating transgenic mice with a TRP channel tagged at the C-terminus with a FP requires detailed investigation of the structural and functional consequences in a given cellular context and fine-tuning the design of specific constructs for a given TRP channel subtype. Different degrees of functional impairment of TRPA1 and TRPC5 constructs suggest a specific importance of the distal C-terminus for the regulation of these two channels in trigeminal neurons.
- MeSH
- červený fluorescenční protein MeSH
- ganglion trigeminale metabolismus MeSH
- genový knockin * MeSH
- kationtové kanály TRPC * genetika metabolismus MeSH
- kationtový kanál TRPA1 * genetika metabolismus MeSH
- luminescentní proteiny * genetika metabolismus MeSH
- myši transgenní * MeSH
- myši MeSH
- rekombinantní fúzní proteiny metabolismus genetika MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Nedd4-2 E3 ligase regulates Na+ homeostasis by ubiquitinating various channels and membrane transporters, including the epithelial sodium channel ENaC. In turn, Nedd4-2 dysregulation leads to various conditions, including electrolytic imbalance, respiratory distress, hypertension, and kidney diseases. However, Nedd4-2 regulation remains mostly unclear. The present study aims at elucidating Nedd4-2 regulation by structurally characterizing Nedd4-2 and its complexes using several biophysical techniques. Our cryo-EM reconstruction shows that the C2 domain blocks the E2-binding surface of the HECT domain. This blockage, ubiquitin-binding exosite masking by the WW1 domain, catalytic C922 blockage and HECT domain stabilization provide the structural basis for Nedd4-2 autoinhibition. Furthermore, Ca2+-dependent C2 membrane binding disrupts C2/HECT interactions, but not Ca2+ alone, whereas 14-3-3 protein binds to a flexible region of Nedd4-2 containing the WW2 and WW3 domains, thereby inhibiting its catalytic activity and membrane binding. Overall, our data provide key mechanistic insights into Nedd4-2 regulation toward fostering the development of strategies targeting Nedd4-2 function.
- MeSH
- elektronová kryomikroskopie MeSH
- HEK293 buňky MeSH
- lidé MeSH
- molekulární modely MeSH
- proteinové domény MeSH
- proteiny 14-3-3 * metabolismus chemie MeSH
- ubikvitinace MeSH
- ubikvitinligasy Nedd4 * metabolismus chemie genetika ultrastruktura MeSH
- vápník * metabolismus MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Alterations in the excitability of dorsal root ganglion (DRG) neurons are critical in the pathogenesis of acute and chronic pain. Neurotransmitter release from the terminals of DRG neurons is regulated by cannabinoid receptor 1 (CB1) and transient receptor potential vanilloid 1 (TRPV1), both activated by anandamide (AEA). In our experiments, the AEA precursor N-arachidonoylphosphatidylethanolamine (20:4-NAPE) was used to study the modulation of nociceptive DRG neurons excitability using K+-evoked Ca2+ transients. Intrathecal administration was used to evaluate in vivo effects. Application of 20:4-NAPE at lower concentrations (10 nM - 1 μM) decreased the excitability of DRG neurons, whereas the higher (10 μM) increased it. Both effects of 20:4-NAPE were blocked by the N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) inhibitor LEI-401. Similarly, lower concentrations of externally applied AEA (1 nM - 10 nM) inhibited DRG neurons, whereas higher concentration (100 nM) did not change it. High AEA concentration (10 μM) evoked Ca2+ transients dependent on TRPV1 activation in separate experiments. Inhibition of the CB1 receptor by PF514273 (400 nM) prevented the 20:4-NAPE- and AEA-induced inhibition, whereas TRPV1 inhibition by SB366791 (1 μM) prevented the increased DRG neuron excitability. In behavioral tests, lower 20:4-NAPE concentration caused hyposensitivity, while higher evoked mechanical allodynia. Intrathecal LEI-401 prevented both in vivo effects of 20:4-NAPE. These results highlight anti- and pro-nociceptive effects of 20:4-NAPE mediated by CB1 and TRPV1 in concentration-dependent manner. Our study underscores the complexity of endocannabinoid signaling in pain transmission modulation and highlights 20:4-NAPE as a potential therapeutic target, offering new insights for developing analgesic strategies.
- MeSH
- endokanabinoidy farmakologie metabolismus MeSH
- fosfatidylethanolaminy * farmakologie MeSH
- fosfolipasa D * metabolismus antagonisté a inhibitory MeSH
- kationtové kanály TRPV metabolismus MeSH
- krysa rodu rattus MeSH
- kyseliny arachidonové * farmakologie MeSH
- neurony * účinky léků metabolismus MeSH
- polynenasycené alkamidy farmakologie MeSH
- potkani Sprague-Dawley MeSH
- receptor kanabinoidní CB1 metabolismus MeSH
- spinální ganglia * účinky léků metabolismus cytologie MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Elevated plasma homocysteine (Hcy) levels lead to hyperhomocysteinemia, a condition associated with various neurological disorders affecting multiple brain regions, including the hippocampus. In this study, we investigated the effects of exposing cultured rat hippocampal neurons to Hcy concentrations corresponding to mild, moderate, and severe hyperhomocysteinemia. A short 24-hour exposure had minimal effects, whereas prolonged exposure up to 14 days moderately enhanced hippocampal excitability without altering the gene expression of voltage-dependent calcium, sodium, or potassium channels or intracellular calcium levels. These findings suggest that Hcy-induced changes in neuronal excitability may contribute to neuropathologies associated with hyperhomocysteinemia.
- MeSH
- hipokampus * cytologie účinky léků MeSH
- homocystein * farmakologie MeSH
- iontové kanály * genetika metabolismus MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- neurony * účinky léků metabolismus cytologie MeSH
- potkani Sprague-Dawley MeSH
- regulace genové exprese * účinky léků MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Membrane contact sites harbor a distinct set of proteins with varying biological functions, thereby emerging as hubs for localized signaling nanodomains underlying adequate cell function. Here, we will focus on mitochondria-associated endoplasmic reticulum membranes (MAMs), which serve as hotspots for Ca2+ signaling, redox regulation, lipid exchange, mitochondrial quality and unfolded protein response pathway. A network of MAM-resident proteins contributes to the structural integrity and adequate function of MAMs. Beyond endoplasmic reticulum (ER)-mitochondrial tethering proteins, MAMs contain several multi-protein complexes that mediate the transfer of or are influenced by Ca2+, reactive oxygen species and lipids. Particularly, IP3 receptors, intracellular Ca2+-release channels, and Sigma-1 receptors (S1Rs), ligand-operated chaperones, serve as important platforms that recruit different accessory proteins and intersect with these local signaling processes. Furthermore, many of these proteins are directly implicated in pathophysiological conditions, where their dysregulation or mutation is not only causing diseases such as cancer and neurodegeneration, but also rare genetic diseases, for example familial Parkinson's disease (PINK1, Parkin, DJ-1), familial Amyotrophic lateral sclerosis (TDP43), Wolfram syndrome1/2 (WFS1 and CISD2), Harel-Yoon syndrome (ATAD3A). In this review, we will discuss the current state-of-the-art regarding the molecular components, protein platforms and signaling networks underlying MAM integrity and function in cell function and how their dysregulation impacts MAMs, thereby driving pathogenesis and/or impacting disease burden. We will highlight how these insights can generate novel, potentially therapeutically relevant, strategies to tackle disease outcomes by improving the integrity of MAMs and the signaling processes occurring at these membrane contact sites.
- MeSH
- endoplazmatické retikulum * metabolismus patologie MeSH
- intracelulární membrány * metabolismus MeSH
- lidé MeSH
- mitochondriální membrány metabolismus MeSH
- mitochondrie * metabolismus patologie MeSH
- nádory * metabolismus patologie terapie genetika MeSH
- neurodegenerativní nemoci * metabolismus patologie terapie genetika MeSH
- receptor sigma-1 MeSH
- receptory sigma metabolismus MeSH
- signální dráha UPR MeSH
- vápníková signalizace MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
BACKGROUND: The neuropeptide B/W signalling system (NPB/W) has been identified in multiple body regions and is integral to several physiological processes, including the regulation of food intake and energy homeostasis. Recently, it has also been detected in human skin; however, its specific functions in this context remain to be thoroughly investigated. This study aims to identify the expression of neuropeptides B/W receptor 1 (NPBWR1) and neuropeptides B/W receptor 2 (NPBWR2) in human dermal fibroblasts of mesenchymal origin using genomic and proteomic techniques. We will also investigate the role of these receptors in cell proliferation and calcium signalling. METHODS: The mRNAs for NPBWR1 and NPBWR2 were detected using quantitative PCR (qPCR) analysis and further validated by western blot and immunofluorescence analyses. Additionally, we synthesised ligands for these receptors, specifically hNPB (25-53) and hNPW (33-62), to investigate their effects on cell proliferation and intracellular calcium levels in human fibroblasts. RESULTS: Our results demonstrated that hNPW (33-62) has anti-proliferative effect on human dermal fibroblasts and concentration of 0.1-μmol/L can significantly decrease intracellular calcium levels (p < 0.05). CONCLUSION: This finding suggests a potential role for the NPB/W signalling system in pathologies associated with impaired calcium handling, such as fibrosis. Furthermore, we observed that the proliferation of human fibroblasts was not affected by hNPB (25-53). Our findings could lead to the development of new therapeutic strategies for various skin conditions and improved wound healing.
- MeSH
- fibroblasty * metabolismus MeSH
- kultivované buňky MeSH
- kůže * metabolismus cytologie MeSH
- lidé MeSH
- neuropeptidy metabolismus genetika MeSH
- proliferace buněk * MeSH
- receptory neuropeptidů metabolismus genetika MeSH
- signální transdukce MeSH
- vápník * metabolismus MeSH
- vápníková signalizace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: Adrenergic activation of protein kinase A (PKA) in cardiac muscle targets the sarcolemma, sarcoplasmic reticulum, and contractile apparatus to increase contractile force and heart rate. In the thin filaments of the contractile apparatus, cardiac troponin I (cTnI) Ser22 and Ser23 in the cardiac-specific N-terminal peptide (NcTnI: residues 1 to 32) are the targets for PKA phosphorylation. Phosphorylation causes a 2-3 fold decrease of affinity of cTn for Ca2+ associated with a higher rate of Ca2+ dissociation from cTnC leading to a faster relaxation rate of the cardiac muscle (lusitropy). Cardiomyopathy-linked mutations primarily affect Ca2+ regulation or the PKA-dependent modulatory system, such that Ca2+-sensitivity becomes independent of phosphorylation level (uncoupling) and this could be sufficient to induce cardiomyopathy. A drug that could restore the phosphorylation-dependent modulation of Ca2+-sensitivity could have potential for treatment of these pathologies. We have found that a number of small molecules, including silybin B, resveratrol and EGCG, can restore coupling in single filament assays. METHODS: We did molecular dynamics simulations (5x1500ns for each condition) of the unphosphorylated and phosphorylated cardiac troponin core with the G159D DCM mutation in the presence of the 5 ligands and analysed the effects on several dynamic parameters. We also studied the effect of the ligands on the contractility of cardiac muscle myocytes with ACTC E99K and TNNT2 R92Q mutations in response to dobutamine. RESULTS: Silybin B, EGCG and resveratrol restored the phosphorylation-induced change in molecular dynamics to wild-type values, whilst silybin A, an inactive isomer of silybin B, and Epicatechin gallate, an EGCG analogue that does not recouple, did not. We analysed the atomic-level changes induced by ligand binding to explain recoupling. Mutations ACTC E99K and TNNT2 R92Q blunt the increased relaxation speed response to β1 adrenergic stimulation of cardiac myocytes and we found that resveratrol, EGCG and silybin B could restore the β1 adrenergic response, whereas silybin A did not. DISCUSSION: The uncoupling phenomenon caused by cardiomyopathy-related mutations and the ability of small molecules to restore coupling in vitro and lusitropy in myocytes is observed at the cellular, molecular and atomistic levels therefore, restoring lusitropy is a suitable target for treatment. Further research on compounds that restore lusitropy is thus indicated as treatments for genetic cardiomyopathies. Further molecular dynamics simulations could define the specific properties needed for recoupling and allow for the prediction and design of potential new drugs.
- Publikační typ
- časopisecké články MeSH
Eryptosis is a regulated cell death (RCD) of mature erythrocytes initially described as a counterpart of apoptosis for enucleated cells. However, over the recent years, a growing number of studies have emphasized certain differences between both cell death modalities. In this review paper, we underline the hallmarks of eryptosis and apoptosis and highlight resemblances and dissimilarities between both RCDs. We summarize and critically discuss differences in the impact of caspase-3, Ca2+ signaling, ROS signaling pathways, opposing roles of casein kinase 1α, protein kinase C, Janus kinase 3, cyclin-dependent kinase 4, and AMP-activated protein kinase to highlight a certain degree of divergence between apoptosis and eryptosis. This review emphasizes the crucial importance of further studies that focus on deepening our knowledge of cell death machinery and identifying novel differences between cell death of nucleated and enucleated cells. This might provide evidence that erythrocytes can be defined as viable entities capable of programmed cell destruction. Additionally, the revealed cell type-specific patterns in cell death can facilitate the development of cell death-modulating therapeutic agents.
T-type calcium channels perform crucial physiological roles across a wide spectrum of tissues, spanning both neuronal and non-neuronal system. For instance, they serve as pivotal regulators of neuronal excitability, contribute to cardiac pacemaking, and mediate the secretion of hormones. These functions significantly hinge upon the intricate interplay of T-type channels with interacting proteins that modulate their expression and function at the plasma membrane. In this review, we offer a panoramic exploration of the current knowledge surrounding these T-type channel interactors, and spotlight certain aspects of their potential for drug-based therapeutic intervention.
