The lipid composition and structure of detergent-resistant membrane rafts from human, goat, and sheep erythrocytes is investigated. While the sphingomyelin:cholesterol ratio varied from about 1:5 in human to 1:1 in sheep erythrocytes a ratio of 1:1 was found in all raft preparations insoluble in Triton X-100 at 4 degrees C. Excess cholesterol is excluded from rafts and saturated molecular species of sphingomyelin assayed by gas chromatography-mass spectrometry determines the solubility of cholesterol in the detergent. Freeze-fracture electron microscopy shows that vesicles and multilamellar structures formed by membrane rafts have undergone considerable rearrangement from the original membrane. No membrane-associated particles are observed. Synchrotron X-ray diffraction studies showed that d spacings of vesicle preparations of rafts cannot be distinguished from ghost membranes from which they are derived. Dispersions of total polar lipid extracts of sheep rafts show phase separation of inverted hexagonal structure upon heating and this phase coexists with multilamellar structures at 37 degrees C.
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http://dx.doi.org/10.1016/j.abb.2004.10.025 | DOI Listing |
Mol Cell
November 2024
School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore. Electronic address:
Ribosomes translating damaged mRNAs may stall and prematurely split into their large and small subunits. The split large ribosome subunits can continue elongating stalled polypeptides. In yeast, this mRNA-independent translation appends the C-terminal alanine/threonine tail (CAT tail) to stalled polypeptides.
View Article and Find Full Text PDFJ Virol
October 2024
Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China.
Structure
October 2024
Laboratory for Alzheimer's Disease, Department of Life Science, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
Intracellular tau aggregation requires a local protein concentration increase, referred to as "droplets". However, the cellular mechanism for droplet formation is poorly understood. Here, we expressed OptoTau, a P301L mutant tau fused with CRY2olig, a light-sensitive protein that can form homo-oligomers.
View Article and Find Full Text PDFInt J Radiat Biol
May 2024
Department of Biophysics and Radiobiology, Institute of Cell Biology and Genetic Engineering, National Academy of Sciences of Ukraine, Kyiv, Ukraine.
Purpose: Ionizing radiation is a harsh environmental factor that could induce plant senescence. We hypothesized that radiation-related senescence remodels proteome, particularly by triggering the accumulation of prion-like proteins in plant tissues. The object of this study, pea ( L.
View Article and Find Full Text PDFCold Spring Harb Perspect Biol
August 2023
Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital-The Norwegian Radium Hospital, 0379 Oslo, Norway.
Extracellular vesicles, such as exosomes, can be used as interesting models to study the structure and function of biological membranes as these vesicles contain only one membrane (i.e., one lipid bilayer).
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