Search Results (381)

Background: Microtubules play a crucial role in neuronal structure and function, with their stability and dynamics regulated by posttranslational modifications (PTMs) such as polyglutamylation. In Alzheimer’s disease (AD), the microtubule-associated protein TAU becomes mislocalized into the somatodendritic compartment (‘TAU missorting’), dissociates from microtubules, aggregates into neurofibrillary tangles, and contributes to microtubule destabilization and neuronal death. Objectives and Methods: Here, we investigated the role of tubulin tyrosine ligase-like proteins (TTLLs) in TAU missorting and microtubule dysregulation using human-induced pluripotent stem cell (hiPSC)-derived cortical neurons treated with oligomeric amyloid-beta (oAβ) to replicate AD-like conditions. TTLL1, TTLL4, and TTLL6 were selectively knocked down (KD) to assess their impact on TAU missorting and microtubule stability. Fluorescence resonance energy transfer (FRET) microscopy was used to examine proximities between TAU and TTLL proteins. Results: We observed TAU missorting, increased tubulin polyglutamylation, decreased tubulin acetylation associated with microtubule destabilization, and synaptic declustering in oAβ-treated neurons. TTLL1 KD significantly reduced TAU missorting, tubulin polyglutamylation, and synaptic disintegration, while TTLL4 KD showed moderate effects, and TTLL6 KD restored microtubule acetylation. Importantly, TTLL KD did not impair neuritic networks, dendritic complexity, or neuronal activity. FRET microscopy in HEK293T cells revealed a close molecular proximity between TAU and TTLL1 consistent with a potential direct or complex-mediated association, but not with other TTLLs, suggesting a direct role of TTLL1 in TAU-mediated toxicity. Conclusions: Our findings identify TTLL1 as a promising therapeutic target for limiting TAU-associated cytoskeletal pathology in AD. These results support further development of pharmacological or genetic strategies targeting TTLL1 as a disease-modifying approach for AD and related tauopathies. Full article

Fever-range hyperthermia (38–41 °C) is a typical physiological response to infection, inflammation, and systemic stress. Although increased temperatures are known to affect blood rheology and erythrocyte activity, their comprehensive impact on red blood cell (RBC) structure, mechanics, and lifespan remains incompletely understood. This review summarizes current understanding of how moderate hyperthermia affects RBC membrane structure, internal behavior, mechanical properties, and clearance cues. Evidence shows that brief exposure to febrile temperatures primarily induces reversible biophysical modifications, including heightened membrane fluidity, increased membrane fluctuations, changes in hemoglobin–water interactions, and short-term improvements in deformability. These changes reflect adaptive adjustments within the membrane–cytosol–cytoskeleton system, potentially temporarily boosting microcirculatory flow. On the other hand, prolonged or repeated heat stress causes oxidative damage, hemoglobin auto-oxidation, accumulation of membrane-bound hemoglobin, band 3 clustering, cytoskeletal restructuring, calcium imbalance, and disruption of membrane lipid asymmetry. These effects weaken membrane stability and lead to vesiculation, shape changes, increased cell fragility, altered aggregation, enhanced adhesion, and activation of clearance mechanisms. A primary focus is the transition from reversible membrane softening to permanent structural damage over time. The research supports a model in which temperature affects RBC mechanics and related membrane, cytosolic, and signaling processes that influence RBC viability. We propose interpreting febrile hyperthermia as a dynamic factor that shifts RBCs from an adaptive phase to accelerated aging and removal during prolonged heat exposure. This perspective enhances our understanding of RBC behavior during fever and systemic inflammation and underscores the role of temperature in shaping erythrocyte function and lifespan. Full article

Type 1 diabetes (T1D) is a systemic metabolic disorder associated with male reproductive dysfunction. Given the pivotal role of actin cytoskeleton remodeling in spermatogenesis and sperm function, this study investigated the effects of T1D on actin-regulating pathways in rat testis and spermatozoa (SPZ). Adult Wistar rats were rendered diabetic by streptozotocin administration (65 mg/kg, i.p.). Testicular analysis revealed a reduced F-/G-actin ratio together with marked F-actin disorganization, consistent with altered actin cytoskeleton remodeling. To investigate the molecular mechanisms underlying these alterations, key regulators of actin dynamics were examined. Diabetic animals displayed impaired expression of EPS8, Fascin, N-WASP, and the ARP2/3 complex, suggesting altered regulation of actin assembly, bundling, and branching. Further analyses demonstrated dysregulation of signaling pathways governing cytoskeletal organization. Reduced levels of phosphorylated Disheveled-2, DAAM1, RhoA-GTP, and ROCK1 indicated impairment of the planar cell polarity pathway. In parallel, changes in LIMK1/cofilin phosphorylation supported abnormal regulation of actin filament turnover. Alterations in the RICTOR/PKC/MARCKS signaling pathway further highlighted defects in cytoskeletal control. Similar abnormalities were observed in mature SPZ, where altered F-actin distribution and DAAM1 localization suggested persistent cytoskeletal defects. Moreover, diabetic SPZ exhibited a reduced ability to undergo acrosome reaction, accompanied by altered MARCKS phosphorylation, highlighting defects in actin-dependent processes essential for sperm function and fertilizing capacity. These findings indicate that disruption of actin cytoskeleton dynamics may represent a major mechanism contributing to testicular and sperm abnormalities in T1D, providing new insights into the mechanisms underlying diabetes-associated male reproductive dysfunction. Full article

The kallikrein–kinin system (KKS) and the kallikrein-related peptidase (KLK) family are interconnected proteolytic networks that regulate inflammatory signaling, vascular permeability, extracellular matrix remodeling, and tissue barrier dynamics. Beyond their classical vasoactive and inflammatory functions, accumulating evidence indicates that kinin peptides, including bradykinin, Lys-bradykinin, and their des-Arg⁹ metabolites, together with selected KLKs, modulate cell–cell and cell–extracellular matrix adhesion. Through B1 and B2 kinin receptor activation, the KKS influences endothelial adhesion molecule expression, leukocyte integrin activation, neutrophil trafficking, focal adhesion kinase/Src signaling, cytoskeletal remodeling, and matrix metalloproteinase activity. In parallel, KLKs directly reshape the adhesive microenvironment by cleaving junctional proteins, including E-cadherin and desmosomal components, and extracellular matrix substrates such as fibronectin, laminin, vitronectin, fibrinogen, and collagens. These coordinated actions affect epithelial and endothelial barrier integrity, leukocyte transmigration, angiogenesis, fibrosis, epithelial–mesenchymal transition, tumor cell migration, invasion, and metastatic dissemination. This review critically summarizes current evidence linking KKS and KLK activity to adhesion-dependent processes in inflammation and cancer, emphasizing how proteolytic signaling may either preserve tissue homeostasis or promote pathological barrier disruption depending on cellular context, receptor expression, protease activity, and microenvironmental cues. Understanding these mechanisms may refine the identification of adhesion-related biomarkers and support the development of targeted therapeutic strategies for inflammatory disorders, fibrotic remodeling, and cancer progression. Full article

The corneal epithelium serves as the outermost transparent barrier of the eye and depends on rapid and coordinated cellular responses for wound repair. Although negative pressure (NP) has been shown to accelerate wound healing in other tissues, its cellular and molecular effects on corneal epithelium remain undefined. This study investigates how NP regulates corneal epithelial cell physiology and identifies the molecular mechanisms underlying NP-induced migration. Human corneal epithelial cells were exposed to normal or NP conditions, and cell motility was quantified using scratch-wound and transwell migration assays. Nuclear and cytoplasmic fractions were isolated for proteomic profiling to identify NP-responsive proteins. G3BP1 was selected as a candidate regulator and subsequently examined using molecular, biochemical, and functional assays to determine its role in NP-mediated signaling. Proteomic analysis revealed a significant NP-induced upregulation of G3BP1. Mechanistically, G3BP1 suppressed epithelial junctional proteins, including E-cadherin, p120-catenin, and ZO-1, while activating key pro-migratory signaling pathways involving AKT, ERK1/2, FAK, and Paxillin. These coordinated changes enhanced cytoskeletal dynamics and promoted corneal epithelial cell migration under NP stimulation. G3BP1 functions as a critical mechanotransduction mediator of NP, orchestrating adhesion remodeling and activating pro-migratory signaling cascades to facilitate corneal epithelial cell motility. These findings reveal a previously unrecognized cellular mechanism through which NP promotes epithelial repair and highlight G3BP1 as a potential therapeutic target for persistent corneal epithelial defects. Full article

Alzheimer’s disease (AD) has a complex pathogenesis, involving molecular and neuroimmune dysregulation, but the causal drivers linking transcriptomic changes to immune remodeling are not yet clear. In a discovery cohort, differential expression analysis was performed, and it was independently validated in two external cohorts. Key genes were prioritized via LASSO/logistic regression, functionally annotated, and causally linked to AD using two-sample MR. The neuroimmune landscape was mapped by ssGSEA, and top candidates were validated in vitro. RGS1 is a key node in neuroinflammation and cytoskeletal dynamics, which is prioritized by the algorithmic intersection. MR analysis suggested a potential causal association between genetically predicted RGS1 expression and AD risk. RGS1 was consistently upregulated in both discovery and validation cohorts (AUC: 0.61–0.67) and was confirmed in vitro. Immune deconvolution showed that AD-specific enrichment profiles occur, and RGS1 is strongly correlated with activated CD4+ T cells and pro-inflammatory chemokines. RGS1 is identified as a robust key gene that may contribute to immune microenvironment dysregulation in AD, and combining discovery-validation transcriptomics, causal inference, and experimental validation, we find that RGS1 is a potential immunomodulatory target. Full article

Despite substantial progress in biomarker discovery and multi-omics profiling, several features of Alzheimer’s disease (AD), including prolonged compensated states, heterogeneous clinical trajectories, and marked stage-dependent therapeutic responses, remain difficult to integrate into a single mechanistic framework. In this review, we propose an integrative and testable conceptual framework that reframes AD as a single, progressive multi-layer network disorder whose dynamics arise from hierarchical constraint propagation and progressive loss of cross-scale coordination. Integrating evidence from human genetics, epigenomics, transcriptomics, proteomics, metabolomics, spatial biology, connectomics, and longitudinal biomarker studies, we examine how molecular, cellular, and circuit-level processes interact over time to shape disease progression. Within this framework, different omics measurements are interpreted as complementary representations of disease-related changes, rather than as independent molecular signatures. Disease progression reflects the gradual convergence of immune, metabolic, proteostatic, cytoskeletal, and synaptic stress, with overt cognitive impairment emerging when compensatory capacity is exceeded, producing threshold-like network destabilization. By explicitly linking biological scale, temporal hierarchy, and network structure, this synthesis extends prior network-medicine, connectomic, and multi-omics approaches into a testable framework for state-aware stratification, integrative analysis, and stage-appropriate therapeutic investigation in AD. Full article

Background: Mechanosensitive ion channels PIEZO1 and PIEZO2 are key mediators of mechanotransduction, which converts physical forces into cellular signals involved in proprioception, touch, vascular function, and other physiological processes. Mutations in human PIEZO proteins are linked to various diseases, such as hereditary xerocytosis, lymphatic dysplasia, and proprioceptive dysfunction. However, the role of intrinsic disorder in the regulation of these proteins and their susceptibility for disease-associated mutations remains unclear. Methods: We analyzed canonical human PIEZO1 and PIEZO2 protein sequences using machine learning, neural network, and energy-based disorder predictors, together with the prediction of disorder-mediated binding regions, phase separation propensity, interaction networks, evolutionary conservation, clinically annotated human variants, and peptide structural modeling. Results: Both proteins showed moderate intrinsic disorder, with PIEZO2 having slightly greater disorder propensity and higher predicted phase separation potential. Intrinsically disordered regions frequently overlapped binding-prone segments and post-translational modification sites, supporting regulatory functions. Evolutionary comparisons showed strong conservation of PIEZO proteins, while selected disordered regions retained disorder propensity despite greater sequence variability. Disease-causing variants mainly affected the ordered regions of both proteins, whereas disordered regions contained proportionally more benign variants and relatively few pathogenic mutations. The modeling of mutations within disordered hotspots showed altered local conformational tendencies, indicating that some disease variants may disrupt dynamic interaction interfaces rather than global structure. Interaction network analysis linked both proteins to enriched mechanotransduction, ion transport, and cytoskeletal pathways. Conclusions: Overall, our findings identify intrinsic disorder as an underappreciated feature of PIEZO channel biology and provide a framework for interpreting PIEZO-associated channelopathies. PIEZO proteins also perfectly illustrate the proteoform concept, where one gene yields a highly diverse kit of mechanosensitive molecular tools. While humans only have two primary PIEZO genes (PIEZO1 and PIEZO2), the body generates a vast array of functional variations. Full article

SASH1 (SAM [sterile alpha motif] and SH3 [SRC-homology-3] domain-containing protein 1) is a multidomain scaffold implicated in pigmentation, innate immunity, receptor signaling, cytoskeletal dynamics, vascular biology, and tumor suppression. Although genetic and expression studies link SASH1 dysfunction to diverse diseases, a unifying mechanistic framework has remained elusive. Here, we synthesize current knowledge of SASH1 structure, interaction networks, and biological functions across cell types and disease contexts. SASH1 contains an intrinsically disordered SPIDER (SLy Proteins Associated Disordered Region), an SH3 domain, two SAM domains, and multiple linear motifs; together, these elements mediate interactions with EphA8 (ephrin type-A receptor 8), β-arrestin 1, TRAF6 (TNF receptor-associated factor 6), CRKL (CRK-like proto-oncogene), IQGAP1 (IQ-motif-containing GTPase-activating protein 1), cortactin, and TNKS2 (tankyrase-2). We propose that SASH1 functions as a context-dependent multi-docking scaffold that organizes signaling architecture. Its modular domains, intrinsically disordered regions, and dual SAM domains enable flexible, multivalent interactions with partners that can be grouped into three functional modules: receptor regulation, intracellular signaling, and cytoskeletal organization. Notably, many SASH1 partners are themselves scaffold or adaptor proteins, allowing integration into pre-existing networks in a hierarchical ‘scaffold-of-scaffolds’ manner. Through selective partner recruitment, SASH1 links cell-surface receptor inputs to downstream signaling pathways and cytoskeletal remodeling. This model provides a mechanistic framework for how SASH1 drives diverse, cell-type-specific outputs across physiology and disease, while revealing broader principles by which multidomain scaffolds encode cellular behavior. Full article

Fluorescence correlation spectroscopy (FCS) measures spontaneous temporal fluorescence fluctuations within a femtolitre observation volume to extract, with single-molecule sensitivity, the concentration, mobility, oligomeric state, and interactions of proteins in living cells. This review traces how FCS and its spatiotemporal derivatives, implemented on different types of optical microscopes, have mapped protein trafficking across the three physically distinct environments a protein must navigate from the cell surface to its genomic targets. At the plasma membrane, FCS resolves nanodomains with millisecond confinement times and distinguishes cytoskeletal corralling from cholesterol-dependent trapping through the FCS diffusion law, revealing how receptor signalling is organised below the diffraction limit. In the cytoplasm, FCS quantifies how macromolecular crowding slows protein diffusion by a factor of 3–4 relative to water, drives anomalous sub-diffusion, and coexists with directed transport, while resolving the markedly slower dynamics of liquid–liquid phase-separated condensates. In the nucleus, FCS-derived pair correlation and brightness analyses show that chromatin acts as a size-selective filter where an inert protein dimer can take more than 10-fold longer than its monomer to traverse the same nuclear distance, and that this oligomeric-state-dependent gating governs the genomic access of transcription factors. Across all three compartments, a protein’s diffusive behaviour is not incidental to its function but is itself a direct readout of the physical organisation of its environment, establishing FCS as a uniquely quantitative bridge between molecular dynamics and cellular decision-making. Full article

Marine heatwaves repeatedly trigger summer mortality of the farmed Pacific oyster (Crassostrea gigas), forcing its haemocytes to reprogramme metabolism under thermal stress. The metabolic nodes governing this adaptation remain poorly defined. Integrating publicly available transcriptomics, single-cell analysis, enzyme inhibition, and molecular dynamics simulation, we identify argininosuccinate synthetase (CgASS) as a key node of this response. Heat stress drove sustained metabolic remodelling of the haemocyte transcriptome, and network analysis placed CgASS at the centre, where it was preferentially expressed in haemocytes and developmentally regulated. Single-cell virtual knockout selectively reshaped minor haemocyte populations, markedly expanding a stress-activated effector population while contracting immunomodulatory and cytoskeletal populations. In vivo inhibition with α-methyl-DL-aspartate raised citrulline, lowered argininosuccinate, and further suppressed respiration and feeding under heat, confirming that CgASS activity sustains aerobic performance. CgASS inactivation constricts arginine supply, thereby depriving both the nNOS–NO pathway that sustains respiration and feeding and the AMD–polyamine pathway that supports cytoprotection. Molecular dynamics revealed that CgASS collapses into an abnormally compact, rigid conformation at 30 °C, constraining the flexibility required for catalysis. Together, these results suggest CgASS as a potential key node of a metabolic compensation–decompensation axis and a molecular target for breeding thermally resilient shellfish. Full article

MicroRNAs (miRNAs) serve as pivotal post-transcriptional modulators of gene expression that govern animal growth and development processes. The present study aimed to investigate the relationship between a single-nucleotide polymorphism (SNP) located within the pre-miR-1453 precursor and growth traits, carcass traits, body size traits, and serum biochemical parameters in an F₂ chicken resource population derived from Gushi and Anka crosses (n = 860). Genotyping of the rs16159272 polymorphism (+31 bp C > T) was performed using MALDI-TOF mass spectrometry, and population genetic parameters, secondary structure prediction, and association analyses were conducted. The results showed that the SNP was moderately polymorphic (PIC = 0.3174) and significantly associated with hatch weight (p < 0.01; CT > TT > CC), as well as body weight at 2 and 4 weeks of age (p < 0.05; TT > CT > CC), but not with carcass or body size traits (p > 0.05). For serum biochemical parameters, total protein, cholinesterase, and creatine phosphokinase showed extremely significant differences across genotypes (p < 0.01), whereas albumin, globulin, and lactate dehydrogenase showed significant differences (p < 0.05). Structural prediction revealed that the C > T mutation increased the minimum free energy by 3.8 kcal/mol, reducing the stability of the pre-miR-1453 stem-loop. Target gene prediction and enrichment analysis indicated that pre-miR-1453 may participate in the regulation of chicken growth and serum biochemical parameters through pathways related to neuron development, cytoskeletal dynamics, and energy metabolism. These findings suggest that the pre-miR-1453 rs16159272 polymorphism could act as a candidate genetic indicator for marker-aided breeding in poultry. Full article

Background: B-cell acute lymphoblastic leukemia (B-ALL) is the most frequent malignancy of childhood; worldwide, 487,294 new cases and 305,405 deaths were reported in 2022, including more than 5000 new cases in Mexico. Chemotherapy, delivered in induction, consolidation and maintenance phases, remains the mainstay of treatment, yet 10–20% of patients relapse after induction because of chemoresistance, whose molecular basis is still incompletely understood. Methods: This retrospective study aimed to identify proteins associated with resistance to vincristine (VCR) and methotrexate (MTX) administered during the induction phase, using LC–MS/MS proteomics and bioinformatic analysis of treatment-naive bone marrow aspirates from responders and nonresponders. Results: Nonresponders showed a distinct proteomic profile, with deregulated processes converging on cytoskeletal structure and dynamics, nucleic acid metabolism, DNA repair and RNA processing. Within these processes, thymidine phosphorylase (TYMP) and gelsolin (GSN) emerged as differentially expressed proteins, both consistently overexpressed in nonresponders at the individual-patient level. Conclusions: We conclude that cytoskeletal remodeling and nucleotide metabolism are prominent features of intrinsic chemoresistance in pediatric B-ALL, and that TYMP and GSN represent candidate biomarkers of nonresponse to VCR- and MTX-based induction that warrant validation by orthogonal methods in independent, adequately powered cohorts. Full article

The herpes simplex virus 1 (HSV-1) US3 is a multifunctional serine/threonine kinase that promotes HSV-1 replication and spread. But its role and the mechanisms by which US3 regulates actin cytoskeletal remodeling remain poorly defined. We combined flow cytometry, confocal microscopy, immunoprecipitation-mass spectrometry (IP-MS), protein complex mapping, and machine learning to characterize US3-mediated F-actin dynamics. Flow cytometry and confocal microscopy showed that wild-type HSV-1 induces significant F-actin remodeling, while the ΔUS3 mutant displays F-actin levels comparable to uninfected cells, identifying US3 as a key regulator. IP-MS identified 47 high-confidence US3 interactors enriched in conserved actin regulatory complexes, including Arp2/3 nucleation machinery, formin-associated assemblies, cofilin severing complexes, and Rho-family GTPase modules. Mapping interactors to the CORUM database revealed clustering within actin nucleation, polymerization, and severing complexes, indicating that US3 operates through organized cellular machines. Machine-learning classifiers trained on label-independent mass-spectrometry features were used to prioritize interactors resembling known actin regulators; under protein-group-aware cross-validation, logistic regression performed best (average precision 0.24; ROC-AUC 0.66), and the analysis was interpreted as prioritization rather than de novo discovery. Pharmacological inhibition of Arp2/3 and formin pathways significantly attenuated US3-dependent F-actin remodeling, supporting the functional involvement of these pathways. Together, these findings are consistent with an inferred hierarchical axis in which US3 modulates Rho GTPase signaling and cofilin activation to promote F-actin disassembly, coordinating cytoskeletal remodeling required for efficient viral egress and spread. Full article

KIF21A, a member of the Kinesin-4 family of motor proteins, is involved in the regulation of microtubule dynamics and intracellular transport, with emerging evidence suggesting its potential role in cancer progression. In this study, we performed an integrative analysis of over 3825 human phosphoproteomics studies to characterize site-specific phosphorylation of KIF21A. Three predominant phosphosites were identified in KIF21A (S853, S1212, and S1239) with the highest detection frequency across phosphoproteomics studies, and were analyzed for co-regulation patterns to identify potential kinase associations and functional networks. Phosphosite S853 showed a strong association with cytoskeletal organization and cortical microtubule stabilization complexes (CMSCs) components, including KANK1 (S186), PHLDB2 (S513, S42) and CLASP1 (S600, S572, S646), indicating its role in cytoskeletal organization. Upstream kinase analysis identified potential regulators, such as PAK2, RPS6KA1/A3, RPS6KB1, CHEK1/2 and CDK18/16 with site-specific variability in their associations with KIF21A predominant sites. Interestingly, phosphosite-specific correlation analysis between KIF21A and candidate kinases revealed that the KIF21A S1239 phosphosite exhibited tumor-specific correlations with CDK18 across multiple cancer types. Functional enrichment revealed that co-regulated phosphoproteins were involved in cytoskeleton regulation, cell cycle regulation, and carcinogenesis. Pan-cancer analysis demonstrated dysregulated expression of KIF21A in multiple tumor types, with stage-associated upregulation in selected cancers. Gene-level validation further supported these findings, showing consistent positive correlations between KIF21A and key regulators such as CTNND1 and PTK2, as well as other cytoskeleton and cancer-associated genes. Overall, this study highlights site-specific phosphorylation as a key regulatory mechanism of KIF21A and suggests its involvement in cytoskeleton-associated signaling networks in cancer. Full article