Conformational activation of radixin by G13 protein alpha subunit

• Published in: The Journal of biological chemistry Vol. 275; no. 34; pp. 26206 - 26212
• Main Authors: Vaiskunaite, R, Adarichev, V, Furthmayr, H, Kozasa, T, Gudkov, A, Voyno-Yasenetskaya, T A
• Format: Journal Article
• Language: English
• Published: United States 25.08.2000
• Subjects: 3T3 Cells; Animals; Blood Proteins - metabolism; Cytoskeletal Proteins - metabolism; GTP-Binding Protein alpha Subunits, G12-G13; Heterotrimeric GTP-Binding Proteins - metabolism; Membrane Proteins - metabolism; Mice; Microfilament Proteins - metabolism; Microscopy, Confocal; Phosphoproteins - metabolism; Protein Binding; Protein Conformation; Signal Transduction; Yeasts
• ISSN: 0021-9258
• DOI: 10.1074/jbc.M001863200

G(13) protein, one of the heterotrimeric guanine nucleotide-binding proteins (G proteins), regulates diverse and complex cellular responses by transducing signals from the cell surface presumably involving more than one pathway. Yeast two-hybrid screening of a mouse brain cDNA library identified radixin, a member of the ERM family of three closely related proteins (ezrin, radixin, and moesin), as a protein that interacted with Galpha(13). Interaction between radixin and Galpha(13) was confirmed by in vitro binding assay and by co-immunoprecipitation technique. Activated Galpha(13) induced conformational activation of radixin, as determined by binding of radixin to polymerized F-actin and by immunofluorescence in intact cells. Finally, two dominant negative mutants of radixin inhibited Galpha(13)-induced focus formation of Rat-1 fibroblasts but did not affect Ras-induced focus formation. Our results identifying a new signaling pathway for Galpha(13) indicate that ERM proteins can be activated by and serve as effectors of heterotrimeric G proteins.