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Opposing views have been proposed regarding the role of tau, the principal microtubule-associated protein in axons. On the one hand, tau forms cross-bridges at the interface between microtubules and induces microtubule bundling in neurons. On the other hand, tau is also considered a polymer brush which efficiently separates microtubules. In mature axons, microtubules are indeed arranged in parallel arrays and are well separated from each other. To reconcile these views, we developed a mechanistic model based on in vitro and cellular approaches combined to analytical and numerical analyses. The results indicate that tau forms long-range cross-bridges between microtubules under macromolecular crowding conditions. Tau cross-bridges prevent the redistribution of tau away from the interface between microtubules, which would have occurred in the polymer brush model. Consequently, the short-range attractive force between microtubules induced by macromolecular crowding is avoided and thus microtubules remain well separated from each other. Interestingly, in this unified model, tau diffusion on microtubules enables to keep microtubules evenly distributed in axonal sections at low tau levels.
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http://dx.doi.org/10.1007/s00018-016-2216-z | DOI Listing |
Sci Adv
September 2025
Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, USA.
Understanding how cells control their biophysical properties during development remains a fundamental challenge. While macromolecular crowding affects multiple cellular processes in single cells, its regulation in living animals remains poorly understood. Using genetically encoded multimeric nanoparticles for in vivo rheology, we found that tissues maintain mesoscale properties that differ from those observed across diverse systems, including bacteria, yeast species, and cultured mammalian cells.
View Article and Find Full Text PDFDev Growth Differ
September 2025
Laboratory for Epithelial Morphogenesis, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.
Multicellular organisms generate organizational complexity through morphogenesis, in which mechanical forces orchestrate the movements and deformations of cells and tissues, while chemical signals regulate the molecular events that generate and coordinate these forces. One common denominator that is critical both for mechanics and biochemistry is material property. Material properties define how materials deform or rearrange under applied forces, and how rapidly molecules interact or spread in space and time.
View Article and Find Full Text PDFEur Phys J E Soft Matter
September 2025
LAAS-CNRS, CNRS, University of Toulouse, Toulouse, France.
Tumor development is accompanied by strong physico-chemical modifications. Among them, compressive stress can emerge in both the epithelial and stromal compartments. Using a simple two-dimensional compression assay which consisted in placing an agarose weight on top of adherent cells, we studied the impact of compressive stress on cell proliferation and motility in different pancreatic cancer cell lines.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan, 030006, China.
Advancing the design and construction of artificial protocells with organized complexity, diverse functionality and practical applicability is urgently demanded in vitro synthetic biology and bioengineering but remains a grand challenge. Here, we present a versatile Pickering emulsion-based encapsulation approach to transform membraneless coacervate compartments into robust multicompartmental hybrid microreactors, which concurrently assimilate the expected attributes of hierarchically compartmentalized structure, molecularly crowded environment, selectively permeable ability and mechanically reinforced stability. Single or multiple biological and non-biological catalytic species can be spatially sequestered in specific domains of the hybrid microreactor, enabling spatiotemporal regulation of individual biocatalysis or divergent cascades with high reaction efficiency.
View Article and Find Full Text PDFJ Phys Chem B
August 2025
School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
Protein-carbohydrate interactions play crucial roles in important biological processes, including cellular differentiation, cell-cell adhesion, mitogenicity, and microbial and viral infections. Our present understanding in this area is largely due to lectins, a unique class of carbohydrate-binding proteins. In view of their ability to differentiate between normal and tumor cells, as well as their potential applications in cancer diagnosis, prognosis, and therapy, it is important to comprehend how the crowding milieu can modulate the structural features and carbohydrate-binding properties of lectins.
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