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NEM inhibits transcytosis, endocytosis, and capillary permeability: implication of caveolae fusion in endothelia
- Source :
- The American journal of physiology. 268(1 Pt 2)
- Publication Year :
- 1995
-
Abstract
- Various vesicular carriers transport select molecular cargo between intracellular compartments utilizing a budding mechanism with docking and fusion of individual vesicles with their target membranes. This fusion requires key intracellular component(s) that are sensitive to alkylation with N-ethylmaleimide (NEM). In endothelium, caveolae may mediate endocytosis and transcytosis of select macromolecules. If caveolae utilize a mechanism similar to other vesicular carriers, then their transport should also be sensitive to NEM. The following tracers were chosen based on their pathway specificity: 1) albumin-gold complexes (A-Au) that bind gp30 and gp18 for endocytosis by caveolae, 2) native albumin that binds albondin and is transported by caveolae, 3) ferritin as a fluid-phase probe transcytosed by caveolae, and 4) inulin as a paracellular probe. In culture, NEM significantly inhibited A-Au uptake and delivery to endosomes but not endothelial cell surface binding. In rat lung, NEM reduced capillary permeability to albumin and the tissue uptake of ferritin and A-Au, but not inulin, indicating inhibition of caveolae-mediated but not paracellular transport. Neutral but not charged alkylating agents inhibited A-Au uptake, consistent with their relative abilities to cross membranes and modify intracellular factors. Like other vesicular pathways, endothelial caveolae transport their select ligands utilizing a NEM-sensitive mechanism, apparently requiring vesicle-membrane fusion.
- Subjects :
- Pulmonary Circulation
Physiology
Endosome
Vascular permeability
Biology
Endocytosis
Capillary Permeability
Rats, Sprague-Dawley
Physiology (medical)
Caveolae
Animals
Lung
Aorta
Cells, Cultured
Vesicle
Microcirculation
Biological Transport
Serum Albumin, Bovine
Phenylmercury Compounds
Cell biology
Capillaries
Rats
Transcytosis
Ethylmaleimide
Paracellular transport
Hydroxymercuribenzoates
Cattle
Endothelium, Vascular
Cardiology and Cardiovascular Medicine
Intracellular
Subjects
Details
- ISSN :
- 00029513
- Volume :
- 268
- Issue :
- 1 Pt 2
- Database :
- OpenAIRE
- Journal :
- The American journal of physiology
- Accession number :
- edsair.doi.dedup.....a4f3d74768e79ffdf71739c070cf7558