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Biochemical Reconstitution of Steroid Receptor•Hsp90 Protein Complexes and Reactivation of Ligand Binding
Published on: September 21, 2011
Interaction between the G alpha subunit of heterotrimeric G(12) protein and Hsp90 is required for G alpha(12)
R Vaiskunaite1, T Kozasa, T A Voyno-Yasenetskaya
1Department of Pharmacology, University of Illinois, Chicago, Illinois 60612-7343, USA.
Abstract:
The G alpha subunit of G(12) protein, one of the heterotrimeric G proteins, regulates diverse and complex cellular responses by transducing signals from the cell surface, presumably involving more than one downstream effector. Yeast two-hybrid screening of a human testis cDNA library identified a large fragment of Hsp90 as a protein that interacted with G alpha(12). The interaction between G alpha(12) and Hsp90 was further substantiated by a co-immunoprecipitation technique. We have determined that Hsp90 is not required for the interaction of G alpha(12) with its binding partners, p115(RhoGEF) and the G beta subunit. Importantly, Hsp90 is required for G alpha(12)-induced serum response element activation, cytoskeletal changes, and mitogenic response. Closely related to G alpha(12), the G alpha(13) subunit did not interact with Hsp90 and did not require functional Hsp90 for serum response element activation. Thus, our results identify a novel signaling module of G alpha(12) and Hsp90.
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