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Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment

Mouse L-fibroblasts internalized large amounts of cationized ferritin (CF) by pinocytosis. Initially (60-90 s after addition of CF to cell monolayers at 37 degrees C), CF was found in vesicles measuring 100-400 nm (sectioned diameter) and as small clusters adhering to the inner aspect of the limitin...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1982
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2112883/
https://www.ncbi.nlm.nih.gov/pubmed/7107699
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description Mouse L-fibroblasts internalized large amounts of cationized ferritin (CF) by pinocytosis. Initially (60-90 s after addition of CF to cell monolayers at 37 degrees C), CF was found in vesicles measuring 100-400 nm (sectioned diameter) and as small clusters adhering to the inner aspect of the limiting membrane of a few large (greater than 600 nm) vacuoles. After 5-30 min, CF labeling of large vacuoles was pronounced and continuous. Moreover, 70-80% of all labeled structures were tiny (less than 100 nm) vesicles. However, the absolute frequency of tiny vesicles increased more than twofold from 5 min to 30 min. When the cells were incubated with CF for 30 min, then washed and further incubated for 3 h without CF, almost all CF was present in dense bodies (100-500 nm). When L-cells were first incubated with horseradish peroxidase (HRP), then washed and incubated with CF, double-labeled vacuoles were observed. Tiny vesicles also contained HRP-CF, and small HRP-CF patches were localized on the cell surface. Distinct labeling of stacked Golgi cisterns was not observed in any experiment. These observations suggest that the numerous tiny vesicles are not endocytic but rather pinch off from the large vacuoles and move towards the cell surface to fuse with the plasma membrane. Thus, ultrastructural evidence is provided in favor of a direct membrane shuttle between the plasma membrane and the lysosomal compartment.
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spelling pubmed-21128832008-05-01 Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment J Cell Biol Articles Mouse L-fibroblasts internalized large amounts of cationized ferritin (CF) by pinocytosis. Initially (60-90 s after addition of CF to cell monolayers at 37 degrees C), CF was found in vesicles measuring 100-400 nm (sectioned diameter) and as small clusters adhering to the inner aspect of the limiting membrane of a few large (greater than 600 nm) vacuoles. After 5-30 min, CF labeling of large vacuoles was pronounced and continuous. Moreover, 70-80% of all labeled structures were tiny (less than 100 nm) vesicles. However, the absolute frequency of tiny vesicles increased more than twofold from 5 min to 30 min. When the cells were incubated with CF for 30 min, then washed and further incubated for 3 h without CF, almost all CF was present in dense bodies (100-500 nm). When L-cells were first incubated with horseradish peroxidase (HRP), then washed and incubated with CF, double-labeled vacuoles were observed. Tiny vesicles also contained HRP-CF, and small HRP-CF patches were localized on the cell surface. Distinct labeling of stacked Golgi cisterns was not observed in any experiment. These observations suggest that the numerous tiny vesicles are not endocytic but rather pinch off from the large vacuoles and move towards the cell surface to fuse with the plasma membrane. Thus, ultrastructural evidence is provided in favor of a direct membrane shuttle between the plasma membrane and the lysosomal compartment. The Rockefeller University Press 1982-08-01 /pmc/articles/PMC2112883/ /pubmed/7107699 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title_full Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title_fullStr Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title_full_unstemmed Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title_short Pinocytosis in mouse L-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
title_sort pinocytosis in mouse l-fibroblasts: ultrastructural evidence for a direct membrane shuttle between the plasma membrane and the lysosomal compartment
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2112883/
https://www.ncbi.nlm.nih.gov/pubmed/7107699