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Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation
Rho-like GTPases, including Cdc42, Rac, and Rho, regulate signaling pathways that control actin cytoskeletal structures and transcriptional activation. The Tiam1 gene encodes an activator of Rac1, and similarly to constitutively activated (V12)Rac1, overexpression of Tiam1 in fibroblasts induces the...
Autores principales: | , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1997
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2139766/ https://www.ncbi.nlm.nih.gov/pubmed/9128250 |
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author | Michiels, Frits Stam, Jord C. Hordijk, Peter L. van der Kammen, Rob A. Stalle, Lisette Ruuls-Van Feltkamp, Constance A. Collard, John G. |
author_facet | Michiels, Frits Stam, Jord C. Hordijk, Peter L. van der Kammen, Rob A. Stalle, Lisette Ruuls-Van Feltkamp, Constance A. Collard, John G. |
author_sort | Michiels, Frits |
collection | PubMed |
description | Rho-like GTPases, including Cdc42, Rac, and Rho, regulate signaling pathways that control actin cytoskeletal structures and transcriptional activation. The Tiam1 gene encodes an activator of Rac1, and similarly to constitutively activated (V12)Rac1, overexpression of Tiam1 in fibroblasts induces the formation of membrane ruffles. Tiam1 contains a Dbl homology (DH) domain and adjacent pleckstrin homology (PH) domain, hallmarks for activators of Rho-like GTPases. Unique for Tiam1 are an additional PH domain and a Discs-large homology region in the NH(2)-terminal part of the protein. Here we show that both in fibroblasts and COS cells, membrane localization of Tiam1 is required for the induction of membrane ruffling. A detailed mutational analysis, in combination with confocal laser scanning microscopy and immunoelectron microscopy, demonstrates that the NH(2)-terminal PH domain of Tiam1, but not the DH-adjacent PH domain, is essential for membrane association. This NH(2)-terminal PH domain of Tiam1 can be functionally replaced by the myristoylated membrane localization domain of c-Src, indicating that the primary function of this PH domain is to localize the protein at the membrane. After serum starvation, both membrane association of Tiam1 and ruffling can be induced by serum, suggesting that receptor stimulation induces membrane translocation of Tiam1. Similar to V12Rac1, Tiam1 stimulates the activity of the c-Jun NH(2)-terminal kinase (JNK). This Rac-dependent stimulation of JNK also requires membrane association of Tiam1. We conclude that the regulated membrane localization of Tiam1 through its NH(2)-terminal PH domain determines the activation of distinct Rac-mediated signaling pathways. |
format | Text |
id | pubmed-2139766 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1997 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21397662008-05-01 Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation Michiels, Frits Stam, Jord C. Hordijk, Peter L. van der Kammen, Rob A. Stalle, Lisette Ruuls-Van Feltkamp, Constance A. Collard, John G. J Cell Biol Article Rho-like GTPases, including Cdc42, Rac, and Rho, regulate signaling pathways that control actin cytoskeletal structures and transcriptional activation. The Tiam1 gene encodes an activator of Rac1, and similarly to constitutively activated (V12)Rac1, overexpression of Tiam1 in fibroblasts induces the formation of membrane ruffles. Tiam1 contains a Dbl homology (DH) domain and adjacent pleckstrin homology (PH) domain, hallmarks for activators of Rho-like GTPases. Unique for Tiam1 are an additional PH domain and a Discs-large homology region in the NH(2)-terminal part of the protein. Here we show that both in fibroblasts and COS cells, membrane localization of Tiam1 is required for the induction of membrane ruffling. A detailed mutational analysis, in combination with confocal laser scanning microscopy and immunoelectron microscopy, demonstrates that the NH(2)-terminal PH domain of Tiam1, but not the DH-adjacent PH domain, is essential for membrane association. This NH(2)-terminal PH domain of Tiam1 can be functionally replaced by the myristoylated membrane localization domain of c-Src, indicating that the primary function of this PH domain is to localize the protein at the membrane. After serum starvation, both membrane association of Tiam1 and ruffling can be induced by serum, suggesting that receptor stimulation induces membrane translocation of Tiam1. Similar to V12Rac1, Tiam1 stimulates the activity of the c-Jun NH(2)-terminal kinase (JNK). This Rac-dependent stimulation of JNK also requires membrane association of Tiam1. We conclude that the regulated membrane localization of Tiam1 through its NH(2)-terminal PH domain determines the activation of distinct Rac-mediated signaling pathways. The Rockefeller University Press 1997-04-21 /pmc/articles/PMC2139766/ /pubmed/9128250 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 | Article Michiels, Frits Stam, Jord C. Hordijk, Peter L. van der Kammen, Rob A. Stalle, Lisette Ruuls-Van Feltkamp, Constance A. Collard, John G. Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title | Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title_full | Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title_fullStr | Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title_full_unstemmed | Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title_short | Regulated Membrane Localization of Tiam1, Mediated by the NH(2)-terminal Pleckstrin Homology Domain, Is Required for Rac-dependent Membrane Ruffling and C-Jun NH(2)-terminal Kinase Activation |
title_sort | regulated membrane localization of tiam1, mediated by the nh(2)-terminal pleckstrin homology domain, is required for rac-dependent membrane ruffling and c-jun nh(2)-terminal kinase activation |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2139766/ https://www.ncbi.nlm.nih.gov/pubmed/9128250 |
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