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Identification of a tight junction-associated guanine nucleotide exchange factor that activates Rho and regulates paracellular permeability

Identification of a tight junction-associated guanine nucleotide exchange factor that activates Rho and regulates paracellular permeability
Identification of a tight junction-associated guanine nucleotide exchange factor that activates Rho and regulates paracellular permeability
Rho family GTPases are important regulators of epithelial tight junctions (TJs); however, little is known about how the GTPases themselves are controlled during TJ assembly and function. We have identified and cloned a canine guanine nucleotide exchange factor (GEF) of the Dbl family of proto-oncogenes that activates Rho and associates with TJs. Based on sequence similarity searches and immunological and functional data, this protein is the canine homologue of human GEF-H1 and mouse Lfc, two previously identified Rho-specific exchange factors known to associate with microtubules in nonpolarized cells. In agreement with these observations, immunofluorescence of proliferating MDCK cells revealed that the endogenous canine GEF-H1/Lfc associates with mitotic spindles. Functional analysis based on overexpression and RNA interference in polarized MDCK cells revealed that this exchange factor for Rho regulates paracellular permeability of small hydrophilic tracers. Although overexpression resulted in increased size-selective paracellular permeability, such cell lines exhibited a normal overall morphology and formed fully assembled TJs as determined by measuring transepithelial resistance and by immunofluorescence and freeze-fracture analysis. These data indicate that GEF-H1/Lfc is a component of TJs and functions in the regulation of epithelial permeability.
epithelia, dbl, intercellular adhesion, actin, microtubules
1932-6203
729-740
Benais-Pont, Gaelle
0c461c35-1757-4a34-b2c0-44cd09711156
Punn, Anu
618013c9-3111-4ede-99c3-f8c160242bc1
Flores-Maldonado, Catalina
b437b304-2c4e-46ab-ac54-7530852fca90
Eckert, Judith
729bfa49-7053-458d-8e84-3e70e4d98e57
Raposo, Graca
d9a66afd-c77d-4afa-9e96-498b35cd5255
Fleming, Tom P.
2abf761a-e5a1-4fa7-a2c8-12e32d5d4c03
Cereijido, Marcelino
703e7758-d513-488d-88b4-4202bcfba580
Balda, Maria S.
c43c4cf3-77d5-456e-981b-5313f0869823
Matter, Karl
1a994ea0-efe1-4c07-b691-aa2d13ddaae0
Benais-Pont, Gaelle
0c461c35-1757-4a34-b2c0-44cd09711156
Punn, Anu
618013c9-3111-4ede-99c3-f8c160242bc1
Flores-Maldonado, Catalina
b437b304-2c4e-46ab-ac54-7530852fca90
Eckert, Judith
729bfa49-7053-458d-8e84-3e70e4d98e57
Raposo, Graca
d9a66afd-c77d-4afa-9e96-498b35cd5255
Fleming, Tom P.
2abf761a-e5a1-4fa7-a2c8-12e32d5d4c03
Cereijido, Marcelino
703e7758-d513-488d-88b4-4202bcfba580
Balda, Maria S.
c43c4cf3-77d5-456e-981b-5313f0869823
Matter, Karl
1a994ea0-efe1-4c07-b691-aa2d13ddaae0

Benais-Pont, Gaelle, Punn, Anu, Flores-Maldonado, Catalina, Eckert, Judith, Raposo, Graca, Fleming, Tom P., Cereijido, Marcelino, Balda, Maria S. and Matter, Karl (2003) Identification of a tight junction-associated guanine nucleotide exchange factor that activates Rho and regulates paracellular permeability. PLoS ONE, 160 (5), 729-740. (doi:10.1083/jcb.200211047).

Record type: Article

Abstract

Rho family GTPases are important regulators of epithelial tight junctions (TJs); however, little is known about how the GTPases themselves are controlled during TJ assembly and function. We have identified and cloned a canine guanine nucleotide exchange factor (GEF) of the Dbl family of proto-oncogenes that activates Rho and associates with TJs. Based on sequence similarity searches and immunological and functional data, this protein is the canine homologue of human GEF-H1 and mouse Lfc, two previously identified Rho-specific exchange factors known to associate with microtubules in nonpolarized cells. In agreement with these observations, immunofluorescence of proliferating MDCK cells revealed that the endogenous canine GEF-H1/Lfc associates with mitotic spindles. Functional analysis based on overexpression and RNA interference in polarized MDCK cells revealed that this exchange factor for Rho regulates paracellular permeability of small hydrophilic tracers. Although overexpression resulted in increased size-selective paracellular permeability, such cell lines exhibited a normal overall morphology and formed fully assembled TJs as determined by measuring transepithelial resistance and by immunofluorescence and freeze-fracture analysis. These data indicate that GEF-H1/Lfc is a component of TJs and functions in the regulation of epithelial permeability.

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More information

Published date: 2003
Keywords: epithelia, dbl, intercellular adhesion, actin, microtubules

Identifiers

Local EPrints ID: 25247
URI: http://eprints.soton.ac.uk/id/eprint/25247
ISSN: 1932-6203
PURE UUID: 163b4704-4a23-4677-94cd-3244a5492a81

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Date deposited: 07 Apr 2006
Last modified: 15 Mar 2024 07:01

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Contributors

Author: Gaelle Benais-Pont
Author: Anu Punn
Author: Catalina Flores-Maldonado
Author: Judith Eckert
Author: Graca Raposo
Author: Tom P. Fleming
Author: Marcelino Cereijido
Author: Maria S. Balda
Author: Karl Matter

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