title: Binding properties and stability of the Ras-association domain of Rap1-GTP interacting adapter molecule (RIAM).
abstract: The Rap1-GTP interacting adapter protein (RIAM) is an important protein in Rap1-mediated integrin activation. By binding to both Rap1 GTPase and talin, RIAM recruits talin to the cell membrane, thus facilitating talin-dependent integrin activation. In this article, we studied the role of the RIAM Ras-association (RA) and pleckstrin-homology (PH) domains in the interaction with Rap1. We found that the RA domain was sufficient for GTP-dependent interaction with Rap1B, and the addition of the PH domain did not change the binding affinity. We also detected GTP-independent interaction of Rap1B with the N-terminus of RIAM. In addition, we found that the PH domain stabilized the RA domain both in vitro and in cells.
authors.affiliation: Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Takala
authors.forename: Jari
authors.initials: J
authors.lastname: Ylänne
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D016608:Talin / Q000378:metabolism; D020668:rap GTP-Binding Proteins / Q000378:metabolism; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C493340:APBB1IP protein, human; D048868:Adaptor Proteins, Signal Transducing; D016023:Integrins; D008565:Membrane Proteins; D016608:Talin; C116753:RAP1B protein, human; D020668:rap GTP-Binding Proteins; D020827:rap1 GTP-Binding Proteins