Rhoa Function in Lamellae Formation and Migration Is Regulated by the α6β4 Integrin and Camp Metabolism
Open Access
- 24 January 2000
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 148 (2), 253-258
- https://doi.org/10.1083/jcb.148.2.253
Abstract
Clone A colon carcinoma cells develop fan-shaped lamellae and exhibit random migration when plated on laminin, processes that depend on the ligation of the α6β4 integrin. Here, we report that expression of a dominant negative RhoA (N19RhoA) in clone A cells inhibited α6β4-dependent membrane ruffling, lamellae formation, and migration. In contrast, expression of a dominant negative Rac (N17Rac1) had no effect on these processes. Using the Rhotekin binding assay to assess RhoA activation, we observed that engagement of α6β4 by either antibody-mediated clustering or laminin attachment resulted in a two- to threefold increase in RhoA activation, compared with cells maintained in suspension or plated on collagen. Antibody-mediated clustering of β1 integrins, however, actually suppressed Rho A activation. The α6β4-mediated interaction of clone A cells with laminin promoted the translocation of RhoA from the cytosol to membrane ruffles at the edges of lamellae and promoted its colocalization with β1 integrins, as assessed by immunofluorescence microscopy. In addition, RhoA translocation was blocked by inhibiting phosphodiesterase activity and enhanced by inhibiting the activity of cAMP-dependent protein kinase. Together, these results establish a specific integrin-mediated pathway of RhoA activation that is regulated by cAMP and that functions in lamellae formation and migration.Keywords
This publication has 28 references indexed in Scilit:
- Rac Downregulates Rho ActivityThe Journal of cell biology, 1999
- Release of cAMP Gating by the α6β4 Integrin Stimulates Lamellae Formation and the Chemotactic Migration of Invasive Carcinoma CellsThe Journal of cell biology, 1998
- cAMP-induced Morphological Changes Are Counteracted by the Activated RhoA Small GTPase and the Rho Kinase ROKαOnline Journal of Public Health Informatics, 1998
- Small GTP-binding Protein Rho Stimulates the Actomyosin System, Leading to Invasion of Tumor CellsOnline Journal of Public Health Informatics, 1998
- The Integrin α6β4 Functions in Carcinoma Cell Migration on Laminin-1 by Mediating the Formation and Stabilization of Actin-containing Motility StructuresThe Journal of cell biology, 1997
- Inhibition of Invasion of Epithelial Cells by Tiam1-Rac SignalingScience, 1997
- Requirement for Rho in Integrin SignallingCell Adhesion and Communication, 1997
- Hemidesmosomes: roles in adhesion, signaling and human diseasesCurrent Opinion in Cell Biology, 1996
- The 70 kDa S6 Kinase Complexes with and Is Activated by the Rho Family G Proteins Cdc42 and Rac1Cell, 1996
- The integrin alpha 6 beta 4 is a laminin receptor.The Journal of cell biology, 1992