The effect of mammalian twinfilin-1 on the structure and dynamics of actin filaments were studied with steady state fluorescence spectroscopy, total internal reflection fluorescence microscopy and differential scanning calorimetry techniques. It was proved before that the eukaryotic budding yeast twinfilin-1 can efficiently bind and severe actin filaments in vitro at low pH values. In the present work steady-state anisotropy measurements revealed that twinfilin can bind efficiently to F-actin. Dilution-induced depolymerization assay proved that mammalian twinfilin-1 has an actin filament severing activity. This severing activity was more pronounced at low pH values. Total internal reflection fluorescence microscopy measurements could support the severing activity of mouse twinfilin-1. The average rate of depolymerization was more apparent at low pH values. The differential scanning calorimetry measurements demonstrated that mammalian twinfilin-1 could reduce the stiffness within the actin filaments before the detachment of the actin protomers. The structural and dynamic reorganization of actin can support the twinfilin-1 induced separation of actin protomers. The measured data indicated that mammalian twinfilin-1 was able to accelerate the monomers dissociation and/or sever the filaments effectively at low pH values. It was concluded that twinfilin-1 can affect the F-actin in biological processes or under stress situations when the pH is markedly under the physiological level.
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http://dx.doi.org/10.1016/j.jphotobiol.2016.09.044 | DOI Listing |
J Mater Chem B
January 2025
Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences, Prague, 18200, Czech Republic.
DNA nanostructures (DNs) have gained popularity in various biomedical applications due to their unique properties, including structural programmability, ease of synthesis and functionalization, and low cytotoxicity. Effective utilization of DNs in biomedical applications requires a fundamental understanding of their interactions with living cells and the mechanics of cellular uptake. Current knowledge primarily focuses on how the physicochemical properties of DNs, such as mass, shape, size, and surface functionalization, affect uptake efficacy.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
January 2025
Department of Life Science, Faculty of Science, Gakushuin University, Mejiro, Tokyo, Japan.
Cytokinesis in animal and fungal cells requires the contraction of actomyosin-based contractile rings formed in the division cortex of the cell during late mitosis. However, the detailed mechanism remains incompletely understood. Here, we aim to develop a novel cell-free system by encapsulating cell extracts obtained from fission yeast cells within lipid vesicles, which subsequently leads to the formation of a contractile ring-like structure inside the vesicles.
View Article and Find Full Text PDFCytoskeleton (Hoboken)
January 2025
Department of Science, Yokohama City University, Yokohama, Japan.
Not only for man-made architecture but also for living cells, the relationship between force and structure is a fundamental properties that governs their mechanical behaviors. However, our knowledge of the mechanical properties of intracellular structures is very limited because of the lack of direct measurement methods. We established high-force intracellular magnetic tweezers that can generate calibrated forces up to 10 nN, enabling direct force measurements of the cytoskeleton.
View Article and Find Full Text PDFFront Immunol
January 2025
Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States.
Introduction: Inflammation is a vital immune response, tightly orchestrated through both biochemical and biophysical cues. Dysregulated inflammation contributes to chronic diseases, highlighting the need for novel therapies that modulate immune responses with minimal side effects. While several biochemical pathways of inflammation are well understood, the influence of physical properties such as substrate curvature on immune cell behavior remains underexplored.
View Article and Find Full Text PDFFEBS J
January 2025
Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Italy.
The trimeric intracellular cation channel B (TRIC-B), encoded by TMEM38B, is a potassium (K) channel present in the endoplasmic reticulum membrane, where it counterbalances calcium (Ca) exit. Lack of TRIC-B activity causes a recessive form of the skeletal disease osteogenesis imperfecta (OI), namely OI type XIV, characterized by impaired intracellular Ca flux and defects in osteoblast (OB) differentiation and activity. Taking advantage of the OB-specific Tmem38b knockout mouse (Runx2Cre;Tmem38b; cKO), we investigated how the ion imbalance affects the osteogenetic process.
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