Search Results (134)

Lipids are commonly viewed as membrane components, energy sources, or precursors of signaling molecules, yet accumulating evidence indicates a broader role in determining the functional state of cells. In this review, we present an integrative cross-domain synthesis in which lipids are discussed as important modulators of cellular functional state across inflammation, tissue regeneration, and chronic disease. We discuss how membrane lipid composition shapes receptor and ion-channel signaling, how bioactive lipid mediators govern the balance between inflammatory initiation and resolution, and how lipid metabolism regulates stem-cell quiescence, activation, and regenerative capacity. We integrate these mechanisms to show how disruption of lipid-regulated processes may bias tissues toward persistent inflammation, impaired repair, and disease progression in conditions such as rheumatic disorders, fibrosis, and neurodegeneration. Depending on context, such lipid alterations may function as causal contributors, permissive conditions, or downstream signatures of pathological state transitions. Finally, we consider how pharmacological and nutritional modulation of lipid pathways may influence cellular states, while emphasizing that the main contribution of this review is a conceptual state-transition framework that links membrane architecture, mediator balance, and lipid metabolic flux across inflammation, regeneration, and chronic disease. Full article

Sterols and sphingolipids assemble into specialized membrane microdomains that are essential for membrane function, protein sorting, and signal transduction. Although coordinated regulation between sterol and sphingolipid metabolic pathways has long been recognized, the molecular mechanisms mediating this cross-talk remain incompletely defined. Here, we uncover an unanticipated role for the conserved yeast Orm proteins in controlling sterol and neutral lipid homeostasis. Deletion of ORM1 and ORM2 causes hypersensitivity to sterol biosynthesis inhibitors, accumulation of steryl esters, and an increase in lipid droplet number. Consistent with mutants lacking core neutral lipid hydrolases, orm1Δ orm2Δ cells display a marked defect in neutral lipid mobilization. These phenotypes depend on sphingolipid pathway perturbation but cannot be attributed to sphingolipid accumulation alone. Together, these findings position the Orm proteins as regulatory nodes linking sterol metabolism, lipid droplet dynamics, and sphingolipid biosynthesis. Full article

Extracellular vesicles (EVs) can disseminate replication-competent viral genomes complexed with selected host proteins, enabling stealth cell-to-cell transfer within lipid membrane-enclosed bubbles. In addition to complementing free-virion spread, EV-associated genomes can be protected from neutralizing antibodies and persist under conditions in which classical virion production decreases. Here, we propose a route-resolved framework in which interconnected cellular secretory pathways, including endoplasmic reticulum (ER) remodeling, multivesicular body (MVB) biogenesis, secretory autophagy, and plasma-membrane budding, jointly generate EV heterogeneity and create discrete opportunities for the capture, protection, and export of infectious cargo. We highlight reticulon-3 (RTN3), an ER-shaping protein, as an upstream regulator that can couple infection-induced ER microdomains to endosomal docking and to autophagy-linked trafficking decisions that bias intermediates toward secretion rather than degradation. Supporting this view, transmission electron microscopy of dengue virus-infected cells reveals extensive vesicular remodeling, including irregular MVBs adjacent to the plasma membrane and autophagosome-like double-membrane structures, consistent with altered vesicular routing following RTN3 perturbation. Collectively, these route-resolved, spatially organized spatio-organelle changes support a pathomechanistic model in which RTN3-mediated ER remodeling reshapes ER-endosome-autophagy trafficking interfaces, creating regulated decision points that can be leveraged to stratify infectious EV subsets (with infectivity-linked single-vesicle and quantitative proteomics approaches) and to inform host-directed strategies that curb non-lytic viral dissemination. Full article

This review surveys how nanoparticles and biomolecular nanosized structures interact with model membrane systems, and how these interfacial processes govern their performance in drug and gene delivery, antimicrobial strategies, biosensing, and nanotoxicology. The nanostructures covered include polymeric nanoparticles, lipid-based carriers, peptide nanostructures, dendrimers, and multifunctional hybrids. Model membranes span Langmuir monolayers, supported lipid bilayers, vesicles/liposomes across sizes, and emerging hybrid or asymmetric constructs that better approximate native complexity. Mechanistically, interactions follow recurrent routes—surface adsorption, bilayer insertion, pore formation, and lipid extraction/reorganization—regulated by particle size, morphology, charge, ligand architecture, and lipophilicity, in conjunction with membrane composition, phase state, curvature, and asymmetry. A multiscale toolkit links structure, mechanics, and dynamics: Langmuir troughs and Brewster Angle Microscopy map thermodynamics and mesoscale morphology; atomic force microscopy and quartz crystal microbalance with dissipation resolve nanoscale topography and viscoelasticity; fluorescence microscopy/spectroscopy reports on localization and packing; neutron and X-ray reflectometry quantify vertical structure; molecular dynamics provides atomistic pathways and design hypotheses. Historically, the field advanced from early monolayers and bilayers, through the fluid mosaic model, to raft microdomains and modern biomimetic systems, enabling increasingly realistic experiments. Key advances include cross-method integration linking experimental observations with image-based computational models; persistent debates concern the translation from simplified models to living membranes, the role of dynamic coronas, and scale/force-field limits in simulations. Future efforts should prioritize hybrid models incorporating proteins and asymmetric lipidomes, standardized reporting and reference systems, rigorous coupling of experiments with calibrated simulations and machine learning, and alignment with safety-by-design and regulatory expectations, thereby shifting interfacial measurements from descriptive observation to predictive design rules. Full article

Current models of the cell membrane assume a heterogenous environment such as sphingomyelin and cholesterol-enriched nano- and microdomains, which are thought to functionally sequester proteins. Besides lipid-ordered domains, membrane proteins can interact with protein complexes by transient binding—necessary for their functional role. Here, we show that an extension of k-space Image Correlation Spectroscopy applied to standard fluorescence microscopy image time series can be used to characterize the protein confinement in heterogeneous membranes. To validate this method, we simulated confined diffusion of tracer particles in a system of static microdomains where we varied the domain size, domain density, confinement probability and diffusion coefficients of tracer particles. We show how the kICS correlation function changes with these parameters and gives rise to emergent properties of the system such as apparent domain sizes and characteristic diffusion coefficients. As a validity check, we apply this analysis to study the dynamics of lipid domain-associated glycosylphosphatidyl inositol (GPI)-anchored proteins labeled by green fluorescent proteins (GPI-GFP) in intact COS-7 cell membranes, and upon domain-disrupting enzyme treatments. Full article

7-ketocholesterol (7-KC) is a bioactive oxysterol generated under oxidative stress and may contribute to bone marrow niche reprogramming in acute myeloid leukemia (AML), thereby promoting stress tolerance and therapeutic resistance Bone marrow mesenchymal stromal cells (MSCs) from healthy donors and AML patients were exposed to subtoxic 7-KC concentrations for 24 h. We evaluated the ABC transporters involved in lipid transport, multidrug resistance and membrane microdomain remodeling; Hedgehog pathway proteins; stress–survival signaling; redox balance by glutathione measurements, and mitochondrial function and dynamics, including membrane potential and gene expression of mitochondrial fission and fusion regulators. Results were integrated using principal component analysis (PCA), heatmaps, and correlation-based networks. Multivariate analyses revealed an integrated, lineage-dependent response. Healthy donor MSCs showed greater plasticity of the efflux and microdomain axis and higher oxidative and mitochondrial vulnerability at high 7-KC doses. AML-MSCs exhibited a basal preconditioned state phenotype and preferentially routed the response toward Hedgehog and stress–survival modules, accompanied by glutathione expansion and adaptive mitochondrial remodeling. 7-KC acts as a broad modulator of several MSC functions, linking sterol homeostasis to Hedgehog signaling, stress–survival pathways, redox balance, and mitochondrial remodeling, potentially supporting a pro-survival, more therapy-tolerant leukemic niche. Full article

Durable responses to cancer immunotherapy remain restricted to a subset of patients, highlighting persistent gaps in understanding immune failure mechanisms. Dendritic cells (DCs) serve as the critical bridge between antigen recognition and adaptive immune activation, yet conventional molecular models centered on discrete components fail to fully explain heterogeneous therapeutic outcomes. This integrative mechanistic synthesis proposes that DC-mediated antitumor immunity is governed by higher-order structural determinants, including membrane microdomain organization, spatial compartmentalization of signaling, and temporal integration of antigenic and co-stimulatory cues. These features determine whether antigen presentation leads to effective T-cell priming or dysfunctional states such as exhaustion or anergy within the tumor microenvironment. By reanalyzing our validated 2025 experimental pipeline alongside high-impact contextual literature, we identify emergent properties of immune competence that transcend linear molecular interactions. The resulting framework distinguishes structurally mediated failure modes from classical resistance paradigms, providing a coherent non-reductionist explanation for variability in immunotherapy efficacy. Membrane raft repair is positioned as a key promising structural condition for effective immune integration, with direct relevance to translational and regulatory contexts involving non-pharmacodynamic platforms and New Approach Methodologies (NAM)-aligned evaluation strategies. This work proposes an integrative mechanistic framework to guide future hypothesis-driven studies and clinical advancement of DC-based approaches. Full article

Electrophysiology, mechanobiology, and the study of soft matter within cells demonstrate increasing amounts of evidence that neuronal signaling arises from interactions between membrane potential, force, and phase. Herein, we have attempted to collect and organize the evidence for each of these areas of study into an approximate structure called the electromechanical connectome: a three-way state–space (membrane potentials, nanoscale mechanical forces, and cytoplasmic rheology, including phase-separated liquid–liquid droplets) where membrane potentials, nanoscale mechanical forces, and cytoplasmic rheology, and phase-separated liquid–liquid droplets are likely to influence one another, influencing synaptic processing, plasticity and network stability. We will also attempt to illustrate the following: how changes in electrostatic fields can be used to alter the arrangement of lipids, hydration, and dielectric microdomains, and the contact geometry between organelles and activity dependent transcription; how mechanical dynamics associated with spines, axons, and the active zone of synapses may be used to modify the energy landscape of channels, the docking and priming of vesicles, and the transport of cytoskeletons; and how viscosity corridors, along with phase-separated micro-reactors, can be used to regulate the kinetics of signaling, molecular trafficking and metabolic processes in local environments. With these connections in mind, we will propose a multiphysical attractor model in which cognition is the result of navigating through metastable manifolds, while neurodegenerative disease may be a result of the progressive loss of electromechanical coherence, phase boundary control and energetic flexibility. Finally, we will present testable hypotheses and use AI-enabled digital twin methods to potentially quantify the early deformation of manifolds and provide precision biomarkers and therapeutic options. Full article

Ion channels are fundamental membrane proteins that mediate selective ion flow across biological membranes and thereby govern excitability, signaling, and homeostasis in virtually all cell types. Although channel function is determined by intrinsic structural features, the surrounding lipid milieu is now recognized as a decisive regulatory layer. Lipids tune ion channel activity through complementary mechanisms: they can bind directly to channel proteins, reshape bilayer physical properties, or act as signaling messengers that couple extracellular cues to channel gating. In addition, the organization of membranes into lipid microdomains such as rafts and caveolae can cluster channels with receptors and scaffolds, enhancing signaling specificity and efficiency. Recent advances in cryo-electron microscopy and molecular simulations have expanded our understanding of these lipid–channel interactions, revealing lipids as active modulators rather than passive structural components. This review provides a comprehensive overview of the principles by which lipids regulate ion channel function and highlights the biological and potential clinical significance of this fundamental interplay. Full article

Mutations in leucine-rich repeat kinase 2 (LRRK2) are among the most common genetic causes of Parkinson’s disease (PD), yet substantial heterogeneity exists among pathogenic variants. How mutations in distinct functional domains of LRRK2 differentially perturb cellular homeostasis remains incompletely understood. Here, we compared two pathogenic LRRK2 mutations—G2019S in the kinase domain and I1371V in the GTPase domain—across multiple cellular models, including SH-SY5Y and U87 cells, and healthy human iPSC-derived floor plate cells. We demonstrate that the I1371V mutation induces markedly more severe cellular dysfunction than G2019S. I1371V-expressing cells exhibited elevated LRRK2 autophosphorylation at S1292 and robust hyperphosphorylation of Rab8A and Rab10, indicating enhanced downstream signaling. These alterations impaired sterol trafficking, leading to selective depletion of membrane cholesterol without changes in total cellular cholesterol. Consequently, I1371V cells displayed increased membrane fluidity, disrupted microdomain organization, altered membrane topology, reduced caveolin-1 expression, and impaired dopamine transporter surface expression and dopamine uptake. Lipidomic profiling further revealed a broad disruption of lipid homeostasis, including reductions in cholesteryl esters, sterols, sphingolipids, and glycerophospholipids, whereas G2019S cells showed comparatively modest changes. Pharmacological intervention revealed mutation-specific responses, with the non-selective LRRK2 modulator GW5074 outperforming the kinase-selective inhibitor MLi-2 in restoring Rab8A phosphorylation, membrane integrity, and dopaminergic function. Collectively, these findings identify membrane lipid dysregulation as a central cell biological mechanism in LRRK2-associated PD and underscore the importance of variant-specific therapeutic strategies. Full article

Serotonergic signaling is traditionally conceived as a transient, vesicle-mediated process restricted to the synaptic cleft. Here, we propose an expanded model in which serotonin can also be inserted into the plasma membrane of neurons and glial cells, forming a stable, membrane-associated reservoir that prolongs its availability beyond classical synaptic timescales. In this framework, the synapse emerges not as a simple neurotransmitter–receptor interface but as a dynamic, multiscale medium where membrane order, hydration, and quantum-level processes jointly govern information flow. Two temporal “tunnels” appear to regulate serotonin bioavailability: its aggregation in synaptic vesicles during exocytosis, and its cholesterol-dependent insertion into neuronal and glial membranes at the tripartite synapse. Lipid raft microdomains enriched in cholesterol and gangliosides thus act as active regulators of a continuum between transient and constitutive serotonin signaling. This extended serotonergic persistence prompts a reconsideration of current pharmacological models and the action of antidepressants such as fluoxetine, which not only inhibits the serotonin transporter (SERT) but also accumulates in lipid rafts, perturbs raft organization, and alters serotonin–cholesterol equilibria, contributing to SERT-independent effects. Grounded in the recently established fundamental parameters of biological systems, this model invites a broader, quantum-informed rethinking of synaptic transmission. Full article

Severe acute respiratory syndrome coronavirus (SARS-CoV) assembles and buds from the Golgi apparatus or the ER membrane, but the specific membrane microdomains utilized during this process remain underexplored. Here, we show that co-expression of the SARS-CoV structural proteins S, M, and N in HEK-293T cells is sufficient to generate genome-free SARS-CoV-like virus-like particles (VLPs), which preferentially bud from glycolipid-enriched membrane lipid raft microdomains. Immunofluorescence microscopy using raft-selective dyes (DiIC16) and spike-specific antibodies revealed strong co-localization of VLPs with lipid rafts. Detergent-resistant membrane analysis and sucrose gradient centrifugation further confirmed the presence of S protein in buoyant, raft-associated fractions alongside the raft marker CD44. Importantly, pharmacological disruption of rafts with methyl-β-cyclodextrin reduced VLP budding and S protein partitioning into raft domains, underscoring the requirement for intact lipid rafts in assembly. Additionally, our data support lipid raft-associated proteins’ (e.g., FNRA, VIM, CD59, RHOA) roles in modulating cellular responses conducive to viral replication and assembly. These findings highlight lipid rafts as crucial platforms for SARS-CoV morphogenesis and suggest new avenues for vaccine and antiviral development using VLPs and raft-targeting therapeutics. Full article

Emerging research indicates that neuronal activity is maintained by an architectural system of protons in a multi-scale fashion. Proton architecture is formed when organelles (such as mitochondria, endoplasmic reticulum, lysosomes, synaptic vesicles, etc.) are coupled together to produce dynamic energy domains. Techniques have been developed to visualize protons in neurons; recent advances include near-atomic structural imaging of organelle interfaces using cryo-tomography and nanoscale resolution imaging of organelle interfaces and proton tracking using ultra-fast spectroscopy. Results of these studies indicate that protons in neurons do not diffuse randomly throughout the neuron but instead exist in organized geometric configurations. The cristae of mitochondrial cells create oscillating proton micro-domains that are influenced by the curvature of the cristae, hydrogen bonding between molecules, and localized changes in dielectric properties that result in time-patterned proton signals that can be used to determine the metabolic load of the cell and the redox state of its mitochondria. These proton patterns also communicate to the rest of the cell via hydrated aligned proton-conductive pathways at the mitochon-dria-endoplasmic reticulum junctions, through acidic lipid regions, and through nano-tethered contact sites between mitochondria and other organelles, which are typically spaced approximately 10–25 nm apart. Other proton architectures exist in lysosomes, endosomes, and synaptic vesicles. In each of these organelles, the V-ATPase generates steep concentration gradients across their membranes, controlling the rate of cargo removal from the lumen of the organelle, recycling receptors from the surface of the membrane, and loading neurotransmitters into the vesicles. Recent super-resolution pH mapping has indicated that populations of synaptic vesicles contain significant heterogeneity in the amount of protons they contain, thereby influencing the amount of neurotransmitter released per vesicle, the probability of vesicle release, and the degree of post-synaptic receptor protonation. Additionally, proton gradients in each organelle interact with the cytoskeleton: the protonation status of actin and microtubules influences filament stiffness, protein–protein interactions, and organelle movement, resulting in the formation of localized spatial structures that may possess some type of computational significance. At multiple scales, it appears that neurons integrate the proton micro-domains with mechanical tension fields, dielectric nanodomains, and phase-state transitions to form distributed computing elements whose behavior is determined by the integration of energy flow, organelle geometry, and the organization of soft materials. Alterations to the proton landscape in neurons (e.g., due to alterations in cristae structure, drift in luminal pH, disruption in the hydration-structure of the cell, or imbalance in the protonation of cytoskeletal components) could disrupt the intracellular signaling network well before the onset of measurable electrical or biochemical pathologies. This article will summarize evidence indicating that proton–organelle interaction provides a previously unknown source of energetic substrate for neural computation. Using an integrated approach combining nanoscale proton energy, organelle interface geometry, cytoskeletal mechanics, and AI-based multiscale models, this article outlines current principles and unresolved questions related to the subject area as well as possible new approaches to early detection and precise intervention of pathological conditions related to altered intracellular energy flow. Full article

The cellular prion protein (PrP^C) displays a functional repertoire that extends well beyond its classical link to transmissible spongiform encephalopathies. Abundant in the nervous system and localized within lipid raft microdomains, PrP^C has emerged as a multifunctional signaling platform that regulates cell differentiation, neurogenesis, neuroprotection, and synaptic plasticity. Recent evidence highlights its dynamic expression in stem cell populations, where it participates in multimolecular complexes that control lineage commitment, particularly during neuronal differentiation. PrP^C expression tightly correlates with stem cell status, making it a promising biomarker of stemness and developmental progression. Through interactions with growth factors, extracellular matrix components, and synaptic proteins, PrP^C functions as a molecular integrator of signals essential for tissue repair and regeneration. Preclinical studies demonstrate that recombinant PrP^C can stimulate neurogenesis and tissue repair, while monoclonal antibodies modulate its physiological and pathological functions. Likewise, cell-based therapies leveraging PrP^C-enriched stem cells or PrP^C-dependent signaling profiles have shown promise in models of neurodegeneration and ischemia. Conversely, dysregulated PrP^C expression has also been observed in solid tumors, where it contributes to cancer cell survival, proliferation, metastasis, and therapy resistance, reinforcing its role as a regulator of cell fate and an oncological target. This review integrates stem cell biology, tissue regeneration, and oncology into a unified framework, offering a novel perspective in which PrP^C emerges as a shared molecular hub governing both physiological repair and pathological tumor behavior, opening previously unrecognized conceptual and translational opportunities. Full article

Pollen tube growth entails complex molecular interactions between the cytoskeletal apparatus and membrane trafficking. Tip growth involves polarized distribution of proteins and lipids along the plasma membrane, including liquid-ordered microdomains, rich in sterols and sphingolipids (lipid rafts), in the apical/subapical region of tobacco pollen tubes. Intriguingly, biochemical characterization of detergent-insoluble membranes purified from tobacco pollen tubes revealed the presence of both actin and tubulin. Here, we report that inhibition of sterol biosynthesis altered lipid rafts and lowered the association of tubulin with detergent-insoluble membranes. Our results showed that sterol depletion increased the number of microtubules in the subapical region, altered microtubule distribution and affected microtubule bundling activity. Oryzalin washout experiments also suggested that lipid-ordered domains could play a role in regulating microtubule nucleation/regrowth. Full article