Spatially restricted activation of signaling molecules governs critical aspects of cell migration; the mechanism by which this is achieved nonetheless remains unknown. Using time-lapse confocal microscopy, we analyzed dynamic redistribution of lipid rafts in chemoattractant-stimulated leukocytes expressing glycosyl phosphatidylinositol-anchored green fluorescent protein (GFP-GPI). Chemoattractants induced persistent GFP-GPI redistribution to the leading edge raft (L raft) and uropod rafts of Jurkat, HL60, and dimethyl sulfoxide-differentiated HL60 cells in a pertussis toxin-sensitive, actin-dependent manner. A transmembrane, nonraft GFP protein was distributed homogeneously in moving cells. A GFP-CCR5 chimera, which partitions in L rafts, accumulated at the leading edge, and CCR5 redistribution coincided with recruitment and activation of phosphatidylinositol-3 kinase gamma in L rafts in polarized, moving cells. Membrane cholesterol depletion impeded raft redistribution and asymmetric recruitment of PI3K to the cell side facing the chemoattractant source. This is the first direct evidence that lipid rafts order spatial signaling in moving mammalian cells, by concentrating the gradient sensing machinery at the leading edge.
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http://dx.doi.org/10.1083/jcb.200309101 | DOI Listing |
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January 2025
Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul, 04620, South Korea.
The MXene, which is usually transition metal carbide, nitride, and carbonitride, is one of the emerging family of 2D materials, exhibiting considerable potential across various research areas. Despite theoretical versatility, practical application of MXene is prohibited due to its spontaneous oxidative degradation. This review meticulously discusses the factors influencing the oxidation of MXenes, considering both thermodynamic and kinetic point of view.
View Article and Find Full Text PDFEJNMMI Phys
January 2025
Sherbrooke Molecular Imaging Center and Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 12th Avenue N, Sherbrooke, J1H 5N4, Québec, Canada.
Background: The renewed interest in BGO scintillators for TOF-PET is driven by the improved Cherenkov photon detection with new blue-sensitive SiPMs. However, the slower scintillation light from BGO causes significant time walk with leading edge discrimination (LED), which degrades the coincidence time resolution (CTR). To address this, a time walk correction (TWC) can be done by using the rise time measured with a second threshold.
View Article and Find Full Text PDFBioinspir Biomim
January 2025
Aerospace Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134, Korea (the Republic of).
This paper describes the tailless control system design of a flapping-wing micro air vehicle in a four-winged configuration, which can provide high control authority to be stable and agile in flight conditions from hovering to maneuvering flights. The tailless control system consists of variable flapping frequency and wing twist modulation. The variable flapping frequency creates rolling moments through differential vertical force from flapping mechanisms that can be independently driven on the left and right sides.
View Article and Find Full Text PDFMolecular docking is a structure-based computational technique that plays a major role in drug discovery. Molecular docking enhances the efficacy of determining the metabolic interaction between two molecules, i.e.
View Article and Find Full Text PDFNanoscale
January 2025
Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J.J.Thomson Avenue, Cambridge CB3 0HE, UK.
Benefiting from improved stability due to interlayer van der Waals interactions, few-layer fullerene networks are experimentally more accessible compared to monolayer polymeric C. However, there is a lack of systematic theoretical studies on the material properties of few-layer C networks. Here, we compare the structural, electronic and optical properties of bilayer and monolayer fullerene networks.
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