Recruitment and activation of Rac1 by the formation of E-cadherin-mediated cell-cell adhesion sites.
J Cell Sci
; 114(Pt 10): 1829-38, 2001 May.
Article
en En
| MEDLINE
| ID: mdl-11329369
ABSTRACT
Rac1, a member of the Rho family small GTPases, regulates E-cadherin-mediated cell-cell adhesion. However, it remains to be clarified how the localization and activation of Rac1 are regulated at sites of cell-cell contact. Here, using enhanced green fluorescence protein (EGFP)-tagged Rac1, we demonstrate that EGFP-Rac1 is colocalized with E-cadherin at sites of cell-cell contact and translocates to the cytosol during disruption of E-cadherin-mediated cell-cell adhesion by Ca(2+) chelation. Re-establishment of cell-cell adhesion by restoration of Ca(2)(+) caused EGFP-Rac1 to become relocalized, together with E-cadherin, at sites of cell-cell contact. Engagement of E-cadherin to the apical membrane by anti-E-cadherin antibody (ECCD-2) recruited EGFP-Rac1. We also investigated whether E-cadherin-mediated cell-cell adhesion induced Rac1 activation by measuring the amounts of GTP-bound Rac1 based on its specific binding to the Cdc42/Rac1 interactive binding region of p21-activated kinase. The formation of E-cadherin-mediated cell-cell adhesion induced Rac1 activation. This activation was inhibited by treatment of cells with a neutralizing antibody (DECMA-1) against E-cadherin, or with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI 3-kinase). IQGAP1, an effector of Rac1, and EGFP-Rac1 behaved in a similar manner during the formation of E-cadherin-mediated cell-cell adhesion. Rac1 activation was also confirmed by measuring the amounts of coimmunoprecipitated Rac1 with IQGAP1 during the establishment of cell-cell adhesion. Taken together, these results suggest that Rac1 is recruited at sites of E-cadherin-mediated cell-cell adhesion and then activated, possibly through PI 3-kinase.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cadherinas
/
Proteína de Unión al GTP rac1
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Proteínas Activadoras de ras GTPasa
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Adhesiones Focales
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Células Epiteliales
Límite:
Animals
Idioma:
En
Revista:
J Cell Sci
Año:
2001
Tipo del documento:
Article
País de afiliación:
Japón