RIAM, an Ena/VASP and Profilin Ligand, Interacts with Rap1-GTP and Mediates Rap1-Induced Adhesion
Author(s)Lafuente, Esther M.; Krause, Matthias; Carman, Christopher V.; Freeman, Gordon J.; Berezovskaya, Alla; Constantine, Erica; Springer, Timothy A.; Boussiotis, Vassiliki A.; Gertler, Frank; van Puijenbroek, Andre A.F.L.; ... Show more Show less
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The small GTPase Rap1 induces integrin-mediated adhesion and changes in the actin cytoskeleton. The mechanisms that mediate these effects of Rap1 are poorly understood. We have identified RIAM as a Rap1-GTP-interacting adaptor molecule. RIAM defines a family of adaptor molecules that contain a RA-like (Ras association) domain, a PH (pleckstrin homology) domain, and various proline-rich motifs. RIAM also interacts with Profilin and Ena/VASP proteins, molecules that regulate actin dynamics. Overexpression of RIAM induced cell spreading and lamellipodia formation, changes that require actin polymerization. In contrast, RIAM knockdown cells had reduced content of polymerized actin. RIAM overexpression also induced integrin activation and cell adhesion. RIAM knockdown displaced Rap1-GTP from the plasma membrane and abrogated Rap1-induced adhesion. Thus, RIAM links Rap1 to integrin activation and plays a role in regulating actin dynamics.
DepartmentMassachusetts Institute of Technology. Department of Biology
Lafuente, Esther M., Andre A.F.L. van Puijenbroek, Matthias Krause, Christopher V. Carman, Gordon J. Freeman, Alla Berezovskaya, Erica Constantine, Timothy A. Springer, Frank B. Gertler, and Vassiliki A. Boussiotis. “RIAM, an Ena/VASP and Profilin Ligand, Interacts with Rap1-GTP and Mediates Rap1-Induced Adhesion.” Developmental Cell 7, no. 4 (October 2004): 585-595. Copyright © 2004 Cell Press
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