Search Results (3,095)

Arabinogalactan proteins (AGPs: hydroxyproline-rich glycoproteins) are ubiquitous in plants and play various functions in cases of development and reproduction. In Arabidopsis thaliana some AGPs can work as markers for gametophytic cell differentiation (among others embryological structures they mark generative cell wall and/or plasma membrane, and also sperm cells). However, apart from Arabidopsis, this labeling of generative cell and sperm cells in pollen grains has only been observed in a few flowering plant species belonging to dicotyledons. No such studies are available in monocotyledons. The main aim of our study was to see whether AGPs would be present at the generative cell–vegetative cell interface in different monocotyledons (representatives of Asparagaceae, Amarylidaceae and Liliaceae), and we also wanted to test whether they would be the same AGPs as in dicotyledons. For the study, we selected Gagea lutea (L.) Ker Gawl., Ornithogalum nutans L. and Galanthus nivalis L. species that differ in shape and size of generative cells. Antibodies against arabinogalactan proteins AGPs were used, including JIM8, JIM13, JIM14, MAC207, LM2, LM14, JIM15 and JIM4. The localization of the examined compounds was determined using immunohistochemistry techniques. The key finding was that AGPs (detected with JIM8 and JIM13 antibodies) consistently mark the boundary between the generative cell and the surrounding vegetative cytoplasm, suggesting their association with the generative cell–vegetative cell interface in all species studied. Identifying such molecular markers in male gametophyte may enhance the understanding of gametophytic cell fate, sperm cell identity and the molecular mechanisms underlying fertilization. Such labeling may also be useful in studies on pollen development, species comparisons, or responses to environmental stresses. Full article

The recruitment of peripheral membrane proteins is tightly regulated by membrane lipid composition and local electrostatic microenvironments. Our experimental observations revealed that Vp54, a viral matrix protein, exhibited preferential binding to lipid bilayers enriched in anionic lipids such as phosphatidylglycerol (PG) and phosphatidylserine (PS), compared to neutral phosphatidylcholine/phosphatidylethanolamine liposomes, and this occurred in a curvature-dependent manner. To elucidate the molecular basis of this selective interaction, we performed a series of computational analyses including helical wheel projection, electrostatic potential calculations, electric field lines simulations, and electrostatic force analysis. Our results showed that the membrane-proximal region of Vp54 adopted an amphipathic α-helical structure with a positively charged interface. In membranes containing PG or PS, electrostatic potentials at the interface were significantly more negative, enhancing attraction with Vp54. Field line and force analyses further confirmed that both the presence and spatial clustering of anionic lipids intensify membrane–Vp54 electrostatic interactions. These computational findings align with experimental binding data, jointly demonstrating that membrane lipid composition and organization critically modulate Vp54 recruitment. Together, our findings highlight the importance of electrostatic complementarity and membrane heterogeneity in peripheral protein targeting and provide a framework applicable to broader classes of membrane-binding proteins. Full article

Background: Endothelial cells (EC), crucial components of the vascular system, are adaptable cells that maintain homeostasis and respond to pathological events through structural and functional plasticity. Hepatocyte growth factor (HGF) is a multifunctional cytokine that has been demonstrated to have protective and disruptive influence on the blood barrier function. In endothelial biology, its role is also poorly characterized. The present study explores the impact of supraphysiological concentrations of HGF on mouse brain endothelial cells (MBECs), scrutinizing how it alters their integrity and morphology. Methods: Two groups of MBECs—control (CTR) and experimental (EXP)—were analyzed at two time points: early passage (p5) and late passage (p41). The EXP-groups (p5 and p41) were treated with HGF at a concentration of 4 µL/mL. Cellular morphology was assessed with brightfield microscopy; protein expression and localization of the tight junction marker (ZO-1) and the endothelial marker (Factor VII related antigen/von Willebrand factor, vWf) were analyzed using Western blotting, immunocytochemistry, and confocal microscopy. Intercellular barrier function was estimated via Transendothelial Electric Resistance (TEER) and Transendothelial Dextran Permeability (TEDP) assays. Results: Microscopical analysis demonstrated a change in the morphology of the MBECs from a longitudinal, spindle-like shape to a rounded, more spheroid, cobblestone-like morphology under high-dose HGF treatment. Western blotting revealed a progressive decrease of ZO-1 expression in the EXP-groups. The expression of vWf did not show significant differences. Qualitative immunocytochemical staining: vWf showed consistent expression across all groups. ZO-1 displayed a punctate, well-defined membrane and cytoplasmic localization pattern in the CTR-groups at p5 and p41. In contrast, the p5 EXP-group demonstrated a shift to a more diffuse cytoplasmic pattern. At p41, the EXP-group displayed a markedly reduced ZO-1 signal with no clear-cut membrane localization. Confocal analysis: ZO-1: punctate membrane-associated localization in CTR-groups at p5 and 41. The EXP-groups at p5 and p41 confirmed the diffuse cytoplasmic ZO-1 distribution. Phalloidin: well-organized actin cytoskeleton in CTR-groups, but rearrangement and stress fiber disorganization in the EXP-groups, especially at p41. The merged images confirmed reduced co-localization of ZO-1 with actin structures. Barrier function: TEER values dropped significantly in HGF-treated cells. TEDP to small and medium molecular weight dextran increased markedly under HGF treatment. Conclusions: Our data demonstrate that supraphysiological doses of HGF in an in vitro MBEC-barrier-like model disrupt TJ organization, leading to morphological changes and functional weakening of the MBEC-barrier-like structure, as shown by uncoupling between ZO-1/F-actin cytoskeleton, reduced TEER, and increased size-selective paracellular permeability (TEDP). Full article

Antimicrobial peptides (AMPs), also referred to as host defense peptides, are promising molecules in the development of the next generation of antibiotics against drug-resistant bacterial pathogens. Thanatin comprises a family of naturally occurring cationic AMPs derived from several species of insects. The first thanatin, 21 residues long, was identified from the spined soldier bug, and more thanatin peptides have been discovered in recent studies. The 16-residue thanatin from Anasa tristis, or Ana-thanatin, represents the shortest sequence in the family. However, the antimicrobial activity and mechanistic process underpinning bacterial cell killing have yet to be reported for Ana-thanatin peptide. In this work, we examined the antibacterial activity, structures, and target interactions of Ana-thanatin. Our results demonstrated that Ana-thanatin exerts potent antibiotic activity against strains of Gram-negative and Gram-positive bacteria. Biophysical studies demonstrated that Ana-thanatin interacts with LPS outer membrane and can permeabilize the OM barrier in the process. Atomic-resolution structures of the peptide in free solution and in complex with lipopolysaccharide (LPS) micelle were solved by NMR, determining canonical β-sheet structures. Notably, in complex with LPS, the β-sheet structure of the peptide was better defined in terms of the packing of amino acid residues. Further, MD simulations demonstrated rapid binding of the Ana-thanatin peptide with the LPS molecules within the lipid bilayers. These studies have revealed structural features which could be responsible for LPS-OM disruption of the Gram-negative bacteria. In addition, NMR heteronuclear single quantum coherence (HSQC) studies have demonstrated that Ana-thanatin can strongly interact with the LPS transport periplasmic protein LptA_m, potentially inhibiting OM biogenesis. Taken together, we surmise that the Ana-thanatin peptide could serve as a template for the further development of novel antibiotics. Full article

During prolonged storage of garlic scapes (Allium sativum L.), the proliferation of microorganisms, particularly fungi, frequently results in postharvest rot, which negatively impacts both product quality and market value. Carvacrol, a promising natural food preservative, exhibits broad-spectrum bioactivity against various microorganisms. In this study, a specific pathogenic fungal strain causing postharvest rot in garlic scapes, designated as HQ, was initially isolated from symptomatic garlic scapes. Based on a combination of physiological characteristics and molecular identification techniques, the HQ strain was identified as Aspergillus niger. Our findings further demonstrated that carvacrol exhibits significant in vitro inhibitory effects against Aspergillus niger with an EC₅₀ value of 75.99 μg/L. Moreover, scanning electron microscopy (SEM) observations revealed that carvacrol induces irreversible morphological and structural changes in the hyphae, resulting in deformation and rupture. Additionally, integrated transcriptomic and proteomic analyses indicated that carvacrol primarily targets the cell wall integrity (CWI) signaling pathway within the mitogen-activated protein kinase (MAPK) signaling pathway in Aspergillus niger, thereby compromising cell membrane integrity and stability, which ultimately suppresses fungal growth and proliferation. Full article

Background: Over the last years, the phenomenon of entosis, a form of cell-in-cell structure, has been highlighted in various tumors, including poorly treatable breast or pancreatic cancers. Nevertheless, not only the biological properties, but also the molecular drivers of entosis remain unclear. Here, we evaluated SRC tyrosine kinase, a key proto-oncogene, and podoplanin (PDPN), a membrane glycoprotein, as potential regulators of entotic cell formation. Methods: In the study, two entosis-competent cell lines, BxPC-3 and MFC-7, originating from pancreatic and breast cancers, respectively, were used. SRC or PDPN genes were silenced using dedicated siRNA and the frequency of entotic structure formation was assessed using fluorescent staining and confocal imaging. Results: It was found that BxPC-3 cells deficient in PDPN are more prone to form entotic structures and that over 90% of all entotic figures formed by mixed PDPN⁺ and PDPN^- BxPC-3 cells involved PDPN-silenced cells. The SRC data supports this observation, as the suppressed entotic formation ability presented by SRC-deficient cells was linked with increased expression of PDPN. Even though the observed effects were mainly limited to BxPC-3 cells, as PDPN expression in MCF-7 cells is restricted, overall, the obtained data suggest a strong anti-entotic function of PDPN. Additionally, the performed Western blotting indicated the activation of ezrin-radixin-moesin (ERM) proteins in PDPN-deficient cells. Conclusions: Taken together, these data suggest that the negatively controlled PDPN-ERM axis may act as a molecular factor controlling the development of entotic structures and cells with naturally low PDPN expression may be more liable to form entoses. Full article

The cellular membrane is a dynamic structure composed of lipids and proteins organized into specialized domains that facilitate interactions between extracellular molecules and the intracellular environment. Tetraspanins are a family of transmembrane proteins involved in diverse cellular processes, including membrane stabilization and fusion, endocytosis, extracellular vesicle formation, and the organization of proteins and lipids at specific membrane sites known as Tetraspanin-Enriched Microdomains (TEMs). These lipid–protein interactions play a critical role in the replicative cycle of Orthoflavivirus, including dengue, Zika, and West Nile, by facilitating viral entry, replication, assembly, and egress. In addition, tetraspanins also regulate the biogenesis and function of extracellular vesicles, contributing to viral dissemination, persistent infection, and immune evasion. This review summarizes the current knowledge on the structural and functional aspects of tetraspanins, their interplay with lipids, and their emerging roles in the Orthoflavivirus replicative cycle. We also discuss how these insights may inform the development of antiviral strategies targeting membrane organization and virus–host interactions. Full article

Prostate stem cell antigen (PSCA) is a Ly6/uPAR protein that targets neuronal nicotinic acetylcholine receptors (nAChRs). It exists in membrane-tethered and soluble forms, with the latter upregulated in Alzheimer’s disease. We hypothesize that PSCA may be linked to a wider spectrum of neurological diseases and could induce neuroinflammation. Indeed, PSCA expression is significantly upregulated in the brain of patients with multiple sclerosis, Huntington’s disease, Down syndrome, bipolar disorder, and HIV-associated dementia. To investigate PSCA’s structure, pharmacology, and inflammatory function, we produced a correctly folded water-soluble recombinant analog (ws-PSCA). In primary hippocampal neurons and astrocytes, ws-PSCA differently regulates secretion of inflammatory factors and adhesion molecules and induces pro-inflammatory responses by increasing TNFβ secretion. Heteronuclear NMR and ¹⁵N relaxation measurements reveal a classical β-structural three-finger fold with conformationally disordered loops II and III. Positive charge clustering on the molecular surface suggests the functional importance of ionic interactions by these loops. Electrophysiological studies in Xenopus oocytes point on ws-PSCA inhibition of α3β2-, high-, and low-sensitive variants of α4β2- (IC₅₀ ~50, 27, and 15 μM, respectively) but not α4β4-nAChRs, suggesting targeting of the β2 subunit. Ensemble docking and molecular dynamics simulations predict PSCA binding to high-sensitive α4β2-nAChR at α4/β2 and β2/β2 interfaces. Complexes are stabilized by ionic and hydrogen bonds between PSCA’s loops II and III and the primary and complementary receptor subunits, including glycosyl groups. This study gives new structural and functional insights into PSCA’s interaction with molecular targets and provides clues to understand its role in the brain function and mental disorders. Full article

The accumulation of high levels of manganese ions complexed with small molecules has been proposed as a pivotal factor contributing to the extraordinary radiation resistance of Deinococcus radiodurans. However, the molecular mechanisms governing the manganese ion homeostasis remain elusive. In this study, we characterize the role of the MntABC transporter system for Mn ion accumulation in D. radiodurans. Its cellular membrane localization is unequivocally demonstrated through fluorescence labeling techniques. Mutation of the protein components of the MntABC led to a significant decrease in intracellular Mn ion accumulation, concomitant with impaired cellular growth, decreased resistance against hydrogen peroxide, and gamma-ray irradiation-induced oxidative stresses, indicating that the MntABC system plays an indispensable role in resistance of D. radiodurans to oxidative stresses. Protein structure modeling and molecular docking are employed to analyze the key active sites of the MntABC proteins and their intermolecular interactions. The results demonstrate that the MntABC system is essential for maintaining Mn ion homeostasis and the oxidative stress resistance of D. radiodurans. Full article

Abiotic stresses severely impair plant growth and productivity. To counteract stress, plants have evolved intricate strategies, including the induction of stress-responsive proteins. The Arabidopsis thaliana Salt Tolerance-Related Protein (STRP) has recently emerged as a key player in abiotic stress tolerance. STRP is a small, hydrophilic, intrinsically disordered protein that exhibits the potential to adopt distinct conformations depending on the cellular context. STRP is localized in the cytosol and nucleus and is associated with the plasma membrane. Stress induces the subcellular redistribution of STRP, accompanied by a significant increase (up to ten-fold) in its levels due to reduced degradation by the 26S proteasome. Reverse genetics studies have demonstrated that STRP can mitigate the detrimental effects of oxidative stress and participate in modulating stress-related gene expression. Although the exact mechanism of STRP remains unclear, its physicochemical properties suggest a dual role as a molecular shield, interacting with macromolecules without a fixed conformation, and as a binder of specific defense-related client proteins, adopting a defined tertiary structure. This review provides a comprehensive overview of STRP and its emerging role as a multifunctional player in abiotic stress responses, also highlighting its potential for strengthening crop resilience and maintaining agricultural productivity under global climate challenges. Full article

Plant sucrose transporters (SUTs) are essential membrane proteins that mediate sucrose phloem loading in source tissues and unloading in sink tissues. In addition to their role in carbohydrate partitioning, SUTs have been implicated in plant responses to both biotic and abiotic stresses. Our previous research demonstrated that silencing StSUT2 in potatoes (Solanum tuberosum) affects plant growth, flowering time, and tuber yield, with transcriptomic analysis suggesting its involvement in cell wall metabolic pathways. In this study, we further investigated the effects of StSUT2 inhibition on the cell wall structure and biotic stress response of potatoes. Transmission electron microscopy revealed that the tuber cell wall thickness of the StSUT2 RNA interference (RNAi) line RNAi-2 was reduced by 7.8%, and the intercellular space was increased by 214% compared with the wild-type plants. Biochemical analyses showed that StSUT2 silencing significantly decreased cellulose, hemicellulose, and lignin contents in both the leaves and tubers, e.g., tuber cellulose reduced by up to 20.1%, while pectin levels remained unaffected, with distinct effects on source leaves and sink tubers’ organs. Additionally, activities of cellulase, xyloglucan glycosyltransferase/hydrolase XTH, and polygalacturonase were elevated in RNAi lines, e.g., leaf cellulase increased by 43.3%, whereas the pectinase activity was unchanged. Pathogen inoculation assays demonstrated that StSUT2 RNAi lines were more susceptible to Ralstonia solanacearum bacterial wilt and Fusarium sulphureum dry rot, showing larger leaf lesions, wider tuber necrotic plaques, and severe seedling wilting. These findings demonstrate that silencing StSUT2 regulates the cell wall structure, composition, and the activity of cell wall-degrading enzymes, thereby reducing the plant’s resistance to fungal and bacterial pathogens. Full article

Background: The increasing prevalence of antibiotic-resistant Mycoplasma genitalium poses a significant challenge to global public health, necessitating the exploration of alternative therapeutic strategies, including vaccine development. Methods: In this study, we employed an immuno-informatics-based reverse vaccinology approach augmented with artificial intelligence-driven tools, to identify and characterize potential B-cell and T-cell epitopes from the hypothetical proteins (HPs) retrieved from the genome of the MG_G37T strain, a previously uncharacterized yet promising vaccine target. Using multiple softwares, a systematic pipeline was utilized to assess the sub-cellular localization, antigenicity, and allergenicity of the selected proteins. Results: Sub-cellular localization analysis identified the presence of several outer membrane and extracellular proteins in the genome of MG_G37T, indicating their surface association and accessibility to immune surveillance. Antigenicity and allergenicity prediction tools led to the identification of two top-scoring hypothetical proteins (fig|2097.71.peg.1 (UniProt ID: P22747) and fig|2097.70.peg.33 (UniProt ID: Q57081)) that demonstrated strong antigenic potential, non-allergenic properties, and suitability as vaccine candidates. Epitope mapping and structural modeling analyses further validated the immunogenic potential of these epitopes, highlighting their ability to interact with host immune components effectively. Comparative analyses with mouse allelic regions indicated the potential translational relevance of these predicted epitopes for preclinical studies. Conclusions: In particular, this study highlights the potential of these two hypothetical proteins as a promising vaccine candidate and provides a strong reason for experimental validation towards the design and development of effective vaccines to combat M. genitalium infections in the era of antimicrobial resistance. Full article

Ice cream is a frozen aerated dessert composed of milk solids, sugars, stabilizers, and fat—with the latter being a key component in defining its structural and sensory properties. This study evaluated the influence of four fat sources—low-trans vegetable fat (T1), butter (T2), UHT cream (T3), and fresh cream (T4)—on the physical and structural characteristics of ice cream, including overrun, melting resistance, texture, color, and rheology, at different stages of processing (before and after maturation). Oscillatory rheological analysis revealed predominantly elastic behavior (G′ > G″) after maturation in all samples, indicating a stable viscoelastic solid structure. Formulations containing T3 and T1 showed the highest overrun values, indicating greater air incorporation, whereas the butter-based formulation (T2) showed the lowest overrun values. Melting resistance followed the following order: T3 > T4 > T2 > T1; therein, the UHT cream formulation exhibited the greatest thermal stability, which was likely due to protein denaturation and aggregation induced by high-temperature processing. Texture analysis showed that the T1 formulation required the lowest maximum extrusion force, while T2 required the highest, reflecting an inverse correlation with overrun values. T1 also displayed the most distinct rheological profile, which was likely due to its specific crystallization behavior and reduced destabilization of the fat globule membrane—which favored the development of a more structured internal network. These findings demonstrate that both the source and processing of fat have a significant impact on the formation of the structural matrix and the final functional properties of ice cream. The results offer technical insights for the development of formulations tailored to specific physical characteristics, optimizing texture, stability, and performance throughout the production process. Full article

The 5th International Symposium on Frontiers in Molecular Science was held on 26–29 August 2025 in Kyoto (Japan), with the support of Kyoto Prefectural University and Kyoto Prefectural University of Medicine. It is evident that the event has proven to be significant, showcasing presentations of pioneering research achievements by internationally renowned researchers and fostering numerous stimulating discussions. The symposium’s objective was to identify and select key research themes within the domain of molecular science. Three plenary lecturers and numerous researchers of outstanding merit were invited by chairs to deliver keynote and invited lectures across six fields: S1. Protein Structure and Molecular Dynamics; S2. Enzymes; S3. Membrane Proteins; S4. Cancer Target Proteins; S5. Drug Design and Solution to Drug Resistance Problem; S6. Physiological Functions of Proteins and Organ Interactions. A total of 185 scientists from 31 countries/regions participated in the symposium with 139 presentations. We would like to express our sincere gratitude to the 31 members of the Scientific Committee and the seven members of the Local Organizing Committee who contributed to enhancing the quality of this symposium, ensuring its smooth operation, and dedicating considerable effort to the selection of each award. Full article

Cadmium (Cd) contamination poses significant threats to aquatic ecosystems. Heavy metal-associated isoprenylated plant proteins (HIPPs) are plant-specific chaperones involved in metal ion homeostasis and stress adaptation. Lotus is an aquatic plant with high biomass and Cd accumulation capacity, showing great potential in water remediation. However, the functional characterization of HIPPs in lotus remains unexplored, limiting its application in phytoremediation. We conducted comprehensive characterization of NnHIPP genes in lotus, integrating comparative genomics, Cd-stress transcriptomics, and heterologous expression assays in transgenic yeast. This study identified 33 NnHIPP genes classified into five subfamilies with conserved motifs and structures. Synteny analysis revealed closer evolutionary relationships with dicots (Arabidopsis and Medicago sativa) than monocots. Abundant stress-responsive elements were found in NnHIPPs promoters. Tissue-specific expression profilings indicated functional diversification across organs and developmental stages. Our transcriptome analysis revealed that most NnHIPPs responded to Cd stress, with stronger induction in roots than leaves. Four Cd-induced NnHIPPs (NnHIPP10/14/21/33) showed both plasma membrane and nuclear localization. Notably, NnHIPP14, NnHIPP21, and NnHIPP33 conferred varying degrees of Cd tolerance when overexpressed in yeast. Our study demonstrates that NnHIPPs participate in Cd stress response. Three candidate NnHIPP genes are proposed for genetic engineering to enhance phytoremediation efficiency in lotus. Full article