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Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis
Ezrin is a component of the microvillus cytoskeleton of a variety of polarized epithelial cells and is believed to function as a membrane- cytoskeletal linker. In this study, we isolated microvilli from human placental syncytiotrophoblast as a model system for biochemical analysis of ezrin function....
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1995
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120629/ https://www.ncbi.nlm.nih.gov/pubmed/8522586 |
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collection | PubMed |
description | Ezrin is a component of the microvillus cytoskeleton of a variety of polarized epithelial cells and is believed to function as a membrane- cytoskeletal linker. In this study, we isolated microvilli from human placental syncytiotrophoblast as a model system for biochemical analysis of ezrin function. In contrast to intestinal microvilli, ezrin is a major protein component of placental microvilli, comprising approximately 5% of the total protein mass and present at about one quarter of the molar abundance of actin. Gel filtration and chemical cross-linking studies demonstrated that ezrin exists mainly in the form of noncovalent dimers and higher order oligomers in extracts of placental microvilli. A novel form of ezrin, apparently representing covalently cross-linked adducts, was present as a relatively minor constituent of placental microvilli. Both oligomers and adducts remained associated with the detergent-insoluble cytoskeleton, indicating a tight interaction with actin filaments. Moreover, stimulation of human A431 carcinoma cells with EGF induces the rapid formation of ezrin oligomers in vivo, thus identifying a signal transduction pathway involving ezrin oligomerization coincident with microvillus assembly. In addition to time course studies, experiments with tyrosine kinase and tyrosine phosphatase inhibitors revealed a correlation between the phosphorylation of ezrin on tyrosine and the onset of oligomer formation, consistent with the possibility that phosphorylation of ezrin might be required for the generation of stable oligomers. Based on these observations, a model for the assembly of cell surface structures is proposed. |
format | Text |
id | pubmed-2120629 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1995 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21206292008-05-01 Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis J Cell Biol Articles Ezrin is a component of the microvillus cytoskeleton of a variety of polarized epithelial cells and is believed to function as a membrane- cytoskeletal linker. In this study, we isolated microvilli from human placental syncytiotrophoblast as a model system for biochemical analysis of ezrin function. In contrast to intestinal microvilli, ezrin is a major protein component of placental microvilli, comprising approximately 5% of the total protein mass and present at about one quarter of the molar abundance of actin. Gel filtration and chemical cross-linking studies demonstrated that ezrin exists mainly in the form of noncovalent dimers and higher order oligomers in extracts of placental microvilli. A novel form of ezrin, apparently representing covalently cross-linked adducts, was present as a relatively minor constituent of placental microvilli. Both oligomers and adducts remained associated with the detergent-insoluble cytoskeleton, indicating a tight interaction with actin filaments. Moreover, stimulation of human A431 carcinoma cells with EGF induces the rapid formation of ezrin oligomers in vivo, thus identifying a signal transduction pathway involving ezrin oligomerization coincident with microvillus assembly. In addition to time course studies, experiments with tyrosine kinase and tyrosine phosphatase inhibitors revealed a correlation between the phosphorylation of ezrin on tyrosine and the onset of oligomer formation, consistent with the possibility that phosphorylation of ezrin might be required for the generation of stable oligomers. Based on these observations, a model for the assembly of cell surface structures is proposed. The Rockefeller University Press 1995-12-01 /pmc/articles/PMC2120629/ /pubmed/8522586 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 Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title | Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title_full | Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title_fullStr | Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title_full_unstemmed | Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title_short | Ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
title_sort | ezrin oligomers are major cytoskeletal components of placental microvilli: a proposal for their involvement in cortical morphogenesis |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120629/ https://www.ncbi.nlm.nih.gov/pubmed/8522586 |