Cargando…
Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells
Trophoblast-like BeWo cells form well-polarized epithelial monolayers, when cultured on permeable supports. Contrary to other polarized cell systems, in which the transferrin receptor is found predominantly on the basolateral cell surface, BeWo cells express the transferrin receptor at both apical a...
Formato: | Texto |
---|---|
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1993
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119860/ https://www.ncbi.nlm.nih.gov/pubmed/8376459 |
_version_ | 1782141359298183168 |
---|---|
collection | PubMed |
description | Trophoblast-like BeWo cells form well-polarized epithelial monolayers, when cultured on permeable supports. Contrary to other polarized cell systems, in which the transferrin receptor is found predominantly on the basolateral cell surface, BeWo cells express the transferrin receptor at both apical and basolateral cell surfaces (Cerneus, D.P., and A. van der Ende. 1991. J. Cell Biol. 114: 1149-1158). In the present study we have addressed the question whether BeWo cells use a different sorting mechanism to target transferrin receptors to the cell surface, by examining the biosynthetic and transcytotic pathways of the transferrin receptor in BeWo cells. Using trypsin and antibodies to detect transferrin receptors at the cell surface of filter-grown BeWo cells, we show that at least 80% of newly synthesized transferrin receptor follows a direct pathway to the basolateral surface, demonstrating that the transferrin receptor is efficiently intracellularly sorted. After surface arrival, pulse-labeled transferrin receptor equilibrates between apical and basolateral cell surfaces, due to ongoing transcytotic transport in both directions. The subsequent redistribution takes over 120 min and results in a steady state distribution with 1.5-2.0 times more transferrin receptors at the basolateral surface than at the apical surface. By monitoring the fate of surface-bound 125I-transferrin, internalized either from the apical or basolateral surface transcytosis of the transferrin receptor was studied. About 15% of 125I-transferrin is transcytosed in the basolateral to apical direction, whereas 25% is transcytosed in the opposite direction, indicated that the fraction of receptors involved in transcytosis is roughly twofold higher for the apical receptor pool, as compared to the basolateral pool. Upon internalization, both apical and basolateral receptor pools become redistributed on both surfaces, resulting in a twofold higher number of transferrin receptors at the basolateral surface. Our results indicate that in BeWo cells bidirectional transcytosis is the main factor in surface distribution of transferrin receptors on apical and basolateral surfaces, which may represent a cell type-specific, post-endocytic, sorting mechanism. |
format | Text |
id | pubmed-2119860 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1993 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21198602008-05-01 Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells J Cell Biol Articles Trophoblast-like BeWo cells form well-polarized epithelial monolayers, when cultured on permeable supports. Contrary to other polarized cell systems, in which the transferrin receptor is found predominantly on the basolateral cell surface, BeWo cells express the transferrin receptor at both apical and basolateral cell surfaces (Cerneus, D.P., and A. van der Ende. 1991. J. Cell Biol. 114: 1149-1158). In the present study we have addressed the question whether BeWo cells use a different sorting mechanism to target transferrin receptors to the cell surface, by examining the biosynthetic and transcytotic pathways of the transferrin receptor in BeWo cells. Using trypsin and antibodies to detect transferrin receptors at the cell surface of filter-grown BeWo cells, we show that at least 80% of newly synthesized transferrin receptor follows a direct pathway to the basolateral surface, demonstrating that the transferrin receptor is efficiently intracellularly sorted. After surface arrival, pulse-labeled transferrin receptor equilibrates between apical and basolateral cell surfaces, due to ongoing transcytotic transport in both directions. The subsequent redistribution takes over 120 min and results in a steady state distribution with 1.5-2.0 times more transferrin receptors at the basolateral surface than at the apical surface. By monitoring the fate of surface-bound 125I-transferrin, internalized either from the apical or basolateral surface transcytosis of the transferrin receptor was studied. About 15% of 125I-transferrin is transcytosed in the basolateral to apical direction, whereas 25% is transcytosed in the opposite direction, indicated that the fraction of receptors involved in transcytosis is roughly twofold higher for the apical receptor pool, as compared to the basolateral pool. Upon internalization, both apical and basolateral receptor pools become redistributed on both surfaces, resulting in a twofold higher number of transferrin receptors at the basolateral surface. Our results indicate that in BeWo cells bidirectional transcytosis is the main factor in surface distribution of transferrin receptors on apical and basolateral surfaces, which may represent a cell type-specific, post-endocytic, sorting mechanism. The Rockefeller University Press 1993-09-02 /pmc/articles/PMC2119860/ /pubmed/8376459 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 Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title | Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title_full | Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title_fullStr | Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title_full_unstemmed | Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title_short | Bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of BeWo cells |
title_sort | bidirectional transcytosis determines the steady state distribution of the transferrin receptor at opposite plasma membrane domains of bewo cells |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119860/ https://www.ncbi.nlm.nih.gov/pubmed/8376459 |