Rings of membrane sterols surround the openings of vesicles and fenestrae, in capillary endothelium.
Open Access
- 1 November 1983
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 97 (5), 1592-1600
- https://doi.org/10.1083/jcb.97.5.1592
Abstract
We investigated the distribution of sterols in the cell membrane of microvascular endothelium (mouse pancreas, diaphragm, brain, heart, lung, kidney, thyroid, adrenal, and liver) with the polyene antibiotic filipin, which reportedly has binding specificity for free 3-beta-hydroxysterols. In some experiments, concomitantly, cell-surface anionic sites were detected with cationized ferritin. Vessels were perfused in situ with PBS, followed by light fixation and filipin administration for 10 to 60 min. Tissues were further processed for thin-section and freeze-fracture electron microscopy. Short exposure (10 min) to filipin-glutaraldehyde solution resulted in the initial appearance, on many areas, of rings of characteristic filipin-sterol complexes within the rim surrounding stomata of most plasmalemmal vesicles, transendothelial channels, and fenestrae. Such rings were absent from the rims of the large openings of the sinusoid endothelium (liver, adrenal), coated pits and phagocytic vacuoles. After longer exposure (30-60 min), filipin-sterol complexes labeled randomly the rest of plasma membrane (except for coated pits, and partially the interstrand areas of junctions), and also marked most plasmalemmal vesicles. These peristomal rings of sterols were displayed mostly on the P face, and, at their full development, consisted of 6-8 units around a vesicle stoma, and 10-12 units around a fenestra. At their level, the intramembranous particles and the cell surface anionic sites were virtually excluded. Peristomal rings of sterols were also detected on the plasma membrane of pericytes and smooth muscle cells of the microvascular wall, which otherwise were poorly labeled with filipin-sterol complexes as compared to endothelial plasmalemma. It is presumed that the peristomal rings of cholesterol may represent important contributors to the local transient stabilization of plasma membrane and to the phase separation between cell membrane and vesicle membrane at a certain stage of their fusion/fission process.Keywords
This publication has 34 references indexed in Scilit:
- Modifications of anionic-lipid domains preceding membrane fusion in guinea pig sperm.The Journal of cell biology, 1982
- Opposite Polarity of Filipin-Induced Deformations in the Membrane of Condensing Vacuoles and Zymogen GranulesScience, 1980
- Heterogeneity of toad bladder granular cell luminal membranes Distribution of filipin-sterol complexes in freeze-fractureBiochimica et Biophysica Acta (BBA) - Biomembranes, 1980
- Lipid polymorphism and the functional roles of lipids in biological membranesBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1979
- Inhomogeneous distribution of filipin–sterol complexes in smooth muscle cell plasma membraneNature, 1979
- Freeze-fracture evidence for the presence of cholesterol in particle-free patches of basal disks and the plasma membrane of retinal rod outer segments of mice and frogs.The Journal of cell biology, 1979
- Interrelated lipid alterations and their influence on the proliferation and fusion of cultured myogenic cellsThe Journal of cell biology, 1978
- Membrane AsymmetryScience, 1977
- The function of sterols in membranesBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1976
- Membrane fusionBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1973