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Bioscience, Biotechnology, and... Jun 2024Deep-sea organisms are subjected to extreme conditions; therefore, understanding their adaptive strategies is crucial. We utilize Saccharomyces cerevisiae as a model to...
Deep-sea organisms are subjected to extreme conditions; therefore, understanding their adaptive strategies is crucial. We utilize Saccharomyces cerevisiae as a model to investigate pressure-dependent protein regulation and piezo-adaptation. Using yeast deletion library analysis, we identified six poorly characterized genes that are crucial for high-pressure growth, forming novel functional modules associated with cell growth. In this study, we aimed to unravel the molecular mechanisms of high-pressure adaptation in S. cerevisiae, focusing on the role of MTC6. MTC6, the gene encoding the novel glycoprotein Mtc6/Ehg2, was found to stabilize tryptophan permease Tat2, ensuring efficient tryptophan uptake and growth under high pressure at 25 MPa. The loss of MTC6 led to promoted vacuolar degradation of Tat2, depending on the Rsp5-Bul1 ubiquitin ligase complex. These findings enhance our understanding of deep-sea adaptations and stress biology, with broad implications for biotechnology, environmental microbiology, and evolutionary insights across species.
PubMed: 38918055
DOI: 10.1093/bbb/zbae086 -
Journal of Hazardous Materials Jun 2024Bivalve hemocytes are oyster immune cells composed of several cellular subtypes with different functions. Hemocytes accumulate high concentrations of copper (Cu) and...
Bivalve hemocytes are oyster immune cells composed of several cellular subtypes with different functions. Hemocytes accumulate high concentrations of copper (Cu) and exert critical roles in metal sequestration and detoxification in oysters, however the specific biochemical mechanisms that govern this have yet to be fully uncovered. Herein, we demonstrate that Cu(I) is predominately sequestered in lysosomes via the Cu transporter ATP7A in hemocytes to reduce the toxic effects of intracellular Cu(I). We also found that Cu(I) is translocated along tunneling nanotubes (TNTs) relocating from high Cu(I) cells to low Cu(I) cells, effectively reducing the burden caused by overloaded Cu(I), and that ATP7A facilitates the efflux of intracellular Cu(I) in both TNTs and hemocyte subtypes. We identify that elevated glutathione (GSH) contents and heat-shock protein (Hsp) levels, as well as the activation of the cell cycle were critical in maintaining the cellular homeostasis and function of hemocytes exposed to Cu. Cu exposure also increased the expression of membrane proteins (MYOF, RalA, RalBP1, and cadherins) and lipid transporter activity which can induce TNT formation, and activated the lysosomal signaling pathway, promoting intercellular lysosomal trafficking dependent on increased hydrolase activity and ATP-dependent activity. This study explores the intracellular and intercellular transport and detoxification of Cu in oyster hemocytes, which may help in understanding the potential toxicity and fate of metals in marine animals.
PubMed: 38917627
DOI: 10.1016/j.jhazmat.2024.135003 -
Physiological regulation of neuronal Wnt activity is essential for TDP-43 localization and function.The EMBO Journal Jun 2024Nuclear exclusion of the RNA- and DNA-binding protein TDP-43 can induce neurodegeneration in different diseases. Diverse processes have been implicated to influence...
Nuclear exclusion of the RNA- and DNA-binding protein TDP-43 can induce neurodegeneration in different diseases. Diverse processes have been implicated to influence TDP-43 mislocalization, including disrupted nucleocytoplasmic transport (NCT); however, the physiological pathways that normally ensure TDP-43 nuclear localization are unclear. The six-transmembrane enzyme glycerophosphodiester phosphodiesterase 2 (GDE2 or GDPD5) cleaves the glycosylphosphatidylinositol (GPI) anchor that tethers some proteins to the membrane. Here we show that GDE2 maintains TDP-43 nuclear localization by regulating the dynamics of canonical Wnt signaling. Ablation of GDE2 causes aberrantly sustained Wnt activation in adult neurons, which is sufficient to cause NCT deficits, nuclear pore abnormalities, and TDP-43 nuclear exclusion. Disruption of GDE2 coincides with TDP-43 abnormalities in postmortem tissue from patients with amyotrophic lateral sclerosis (ALS). Further, GDE2 deficits are evident in human neural cell models of ALS, which display erroneous Wnt activation that, when inhibited, increases mRNA levels of genes regulated by TDP-43. Our study identifies GDE2 as a critical physiological regulator of Wnt signaling in adult neurons and highlights Wnt pathway activation as an unappreciated mechanism contributing to nucleocytoplasmic transport and TDP-43 abnormalities in disease.
PubMed: 38918634
DOI: 10.1038/s44318-024-00156-8 -
Cell Death & Disease Jun 2024Multiple sevoflurane exposures may damage the developing brain. The neuroprotective function of dexmedetomidine has been widely confirmed in animal experiments and human...
Multiple sevoflurane exposures may damage the developing brain. The neuroprotective function of dexmedetomidine has been widely confirmed in animal experiments and human studies. However, the effect of dexmedetomidine on the glymphatic system has not been clearly studied. We hypothesized that dexmedetomidine could alleviate sevoflurane-induced circulatory dysfunction of the glymphatic system in young mice. Six-day-old C57BL/6 mice were exposed to 3% sevoflurane for 2 h daily, continuously for 3 days. Intraperitoneal injection of either normal saline or dexmedetomidine was administered before every anaesthesia. Meanwhile the circulatory function of glymphatic system was detected by tracer injection at P8 and P32. On P30-P32, behavior tests including open field test, novel object recognition test, and Y-maze test were conducted. Primary astrocyte cultures were established and treated with the PI3K activator 740Y-P, dexmedetomidine, and small interfering RNA (siRNA) to silence ΔFosB. We propose for the first time that multiple exposure to sevoflurane induces circulatory dysfunction of the glymphatic system in young mice. Dexmedetomidine improves the circulatory capacity of the glymphatic system in young mice following repeated exposure to sevoflurane through the PI3K/AKT/ΔFosB/AQP4 signaling pathway, and enhances their long-term learning and working memory abilities.
Topics: Animals; Dexmedetomidine; Sevoflurane; Glymphatic System; Proto-Oncogene Proteins c-akt; Mice; Mice, Inbred C57BL; Phosphatidylinositol 3-Kinases; Aquaporin 4; Signal Transduction; Astrocytes; Male
PubMed: 38918408
DOI: 10.1038/s41419-024-06845-w -
Science Signaling Jun 2024Palmitoylation of intact or cleaved gasdermin D causes plasma membrane pore formation.
Palmitoylation of intact or cleaved gasdermin D causes plasma membrane pore formation.
Topics: Lipoylation; Humans; Cell Membrane; Intracellular Signaling Peptides and Proteins; Animals; Gasdermins; Phosphate-Binding Proteins
PubMed: 38917221
DOI: 10.1126/scisignal.adr1306 -
PloS One 2024Gulf War Illness (GWI) is a chronic condition characterized by multisystem symptoms that still affect up to one-third of veterans who engaged in combat in the Gulf War...
Gulf War Illness (GWI) is a chronic condition characterized by multisystem symptoms that still affect up to one-third of veterans who engaged in combat in the Gulf War three decades ago. The aetiology of GWI is mainly explained by exposure to multiple toxic agents, vaccines, and medications. As there is a significant overlap in symptoms between GWI and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), the objective of this study was to investigate a biomarker widely reported in Natural Killer (NK) cells from ME/CFS patients, the Transient Receptor Potential Melastatin 3 (TRPM3) ion channel. NK cells from 6 healthy controls (HC) and 6 GWI participants were isolated, and TRPM3 function was assessed through whole-cell patch-clamp. As demonstrated by prior studies, NK cells from HC expressed typical TRPM3 function after pharmacomodulation. In contrast, this pilot investigation demonstrates a dysfunctional TRPM3 in NK cells from GWI participants through application of a TRPM3 agonist and confirmed by a TRPM3 antagonist. There was a significant reduction in TRPM3 function from GWI than results measured in HC. This study provides an unprecedented research field to investigate the involvement of TRP ion channels in the pathomechanism and potential medical interventions to improve GWI quality of life.
Topics: Humans; TRPM Cation Channels; Persian Gulf Syndrome; Killer Cells, Natural; Male; Middle Aged; Adult; Female; Case-Control Studies; Patch-Clamp Techniques
PubMed: 38917121
DOI: 10.1371/journal.pone.0305704 -
Proceedings of the National Academy of... Jul 2024HCN1-4 channels are the molecular determinants of the I/I current that crucially regulates cardiac and neuronal cell excitability. HCN dysfunctions lead to sinoatrial...
HCN1-4 channels are the molecular determinants of the I/I current that crucially regulates cardiac and neuronal cell excitability. HCN dysfunctions lead to sinoatrial block (HCN4), epilepsy (HCN1), and chronic pain (HCN2), widespread medical conditions awaiting subtype-specific treatments. Here, we address the problem by solving the cryo-EM structure of HCN4 in complex with ivabradine, to date the only HCN-specific drug on the market. Our data show ivabradine bound inside the open pore at 3 Å resolution. The structure unambiguously proves that Y507 and I511 on S6 are the molecular determinants of ivabradine binding to the inner cavity, while F510, pointing outside the pore, indirectly contributes to the block by controlling Y507. Cysteine 479, unique to the HCN selectivity filter (SF), accelerates the kinetics of block. Molecular dynamics simulations further reveal that ivabradine blocks the permeating ion inside the SF by electrostatic repulsion, a mechanism previously proposed for quaternary ammonium ions.
Topics: Ivabradine; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; Molecular Dynamics Simulation; Humans; Cryoelectron Microscopy; Animals; Potassium Channels; Muscle Proteins
PubMed: 38917012
DOI: 10.1073/pnas.2402259121 -
Proceedings of the National Academy of... Jul 2024S100A1, a small homodimeric EF-hand Ca-binding protein (~21 kDa), plays an important regulatory role in Ca signaling pathways involved in various biological functions...
S100A1, a small homodimeric EF-hand Ca-binding protein (~21 kDa), plays an important regulatory role in Ca signaling pathways involved in various biological functions including Ca cycling and contractile performance in skeletal and cardiac myocytes. One key target of the S100A1 interactome is the ryanodine receptor (RyR), a huge homotetrameric Ca release channel (~2.3 MDa) of the sarcoplasmic reticulum. Here, we report cryoelectron microscopy structures of S100A1 bound to RyR1, the skeletal muscle isoform, in absence and presence of Ca. Ca-free apo-S100A1 binds beneath the bridging solenoid (BSol) and forms contacts with the junctional solenoid and the shell-core linker of RyR1. Upon Ca-binding, S100A1 undergoes a conformational change resulting in the exposure of the hydrophobic pocket known to serve as a major interaction site of S100A1. Through interactions of the hydrophobic pocket with RyR1, Ca-bound S100A1 intrudes deeper into the RyR1 structure beneath BSol than the apo-form and induces sideways motions of the C-terminal BSol region toward the adjacent RyR1 protomer resulting in tighter interprotomer contacts. Interestingly, the second hydrophobic pocket of the S100A1-dimer is largely exposed at the hydrophilic surface making it prone to interactions with the local environment, suggesting that S100A1 could be involved in forming larger heterocomplexes of RyRs with other protein partners. Since S100A1 interactions stabilizing BSol are implicated in the regulation of RyR-mediated Ca release, the characterization of the S100A1 binding site conserved between RyR isoforms may provide the structural basis for the development of therapeutic strategies regarding treatments of RyR-related disorders.
Topics: Ryanodine Receptor Calcium Release Channel; S100 Proteins; Calcium; Cryoelectron Microscopy; Animals; Protein Binding; Binding Sites; Models, Molecular; Protein Conformation; Humans
PubMed: 38917010
DOI: 10.1073/pnas.2400497121 -
Proceedings of the National Academy of... Jul 2024Spinal cord dorsal horn inhibition is critical to the processing of sensory inputs, and its impairment leads to mechanical allodynia. How this decreased inhibition...
Spinal cord dorsal horn inhibition is critical to the processing of sensory inputs, and its impairment leads to mechanical allodynia. How this decreased inhibition occurs and whether its restoration alleviates allodynic pain are poorly understood. Here, we show that a critical step in the loss of inhibitory tone is the change in the firing pattern of inhibitory parvalbumin (PV)-expressing neurons (PVNs). Our results show that PV, a calcium-binding protein, controls the firing activity of PVNs by enabling them to sustain high-frequency tonic firing patterns. Upon nerve injury, PVNs transition to adaptive firing and decrease their PV expression. Interestingly, decreased PV is necessary and sufficient for the development of mechanical allodynia and the transition of PVNs to adaptive firing. This transition of the firing pattern is due to the recruitment of calcium-activated potassium (SK) channels, and blocking them during chronic pain restores normal tonic firing and alleviates chronic pain. Our findings indicate that PV is essential for controlling the firing pattern of PVNs and for preventing allodynia. Developing approaches to manipulate these mechanisms may lead to different strategies for chronic pain relief.
Topics: Parvalbumins; Animals; Chronic Pain; Mice; Neurons; Hyperalgesia; Male; Action Potentials; Small-Conductance Calcium-Activated Potassium Channels
PubMed: 38916998
DOI: 10.1073/pnas.2403777121 -
Blood Advances Jun 2024The Glucose transporter 1 (GLUT1) is one of the most abundant proteins within the erythrocyte membrane and is required for glucose and dehydroascorbic acid (Vitamin C...
The Glucose transporter 1 (GLUT1) is one of the most abundant proteins within the erythrocyte membrane and is required for glucose and dehydroascorbic acid (Vitamin C precursor) transport. It is widely recognized as a key protein for red cell structure, function, and metabolism. Previous reports highlighted the importance of GLUT1 activity within these uniquely glycolysis-dependent cells, in particular for increasing antioxidant capacity needed to avoid irreversible damage from oxidative stress in humans. However, studies of glucose transporter roles in erythroid cells are complicated by species-specific differences between humans and mice. Here, using CRISPR-mediated gene editing of immortalized erythroblasts and adult CD34+ hematopoietic progenitor cells, we generate committed human erythroid cells completely deficient in expression of GLUT1. We show that absence of GLUT1 does not impede human erythroblast proliferation, differentiation, or enucleation. This work demonstrates for the first-time generation of enucleated human reticulocytes lacking GLUT1. The GLUT1-deficient reticulocytes possess no tangible alterations to membrane composition or deformability in reticulocytes. Metabolomic analyses of GLUT1-deficient reticulocytes reveal hallmarks of reduced glucose import, downregulated metabolic processes and upregulated AMPK-signalling, alongside alterations in antioxidant metabolism, resulting in increased osmotic fragility and metabolic shifts indicative of higher oxidant stress. Despite detectable metabolic changes in GLUT1 deficient reticulocytes, the absence of developmental phenotype, detectable proteomic compensation or impaired deformability comprehensively alters our understanding of the role of GLUT1 in red blood cell structure, function and metabolism. It also provides cell biological evidence supporting clinical consensus that reduced GLUT1 expression does not cause anaemia in GLUT1 deficiency syndrome.
PubMed: 38916993
DOI: 10.1182/bloodadvances.2024012743