Direct interactions between the heterotrimeric G protein subunit G beta 5 and the G protein gamma subunit-like domain-containing regulator of G protein signaling 11: gain of function of cyan fluorescent protein-tagged G gamma 3.
We used fluorescence resonance energy transfer imaging of enhanced cyan fluorescent protein (CFP)-tagged and enhanced yellow fluorescent protein (YFP)-tagged protein pairs to examine the hypothesis that G protein gamma subunit-like (GGL) domain-containing regulators of G protein signaling (RGS) can directly bind to the Gbeta5 subunit of heterotrimeric G proteins in vivo. We observed that Gbeta5 could interact with Ggamma2 and Ggamma13, after their expression in human embryonic kidney 293 cells. Interestingly, although untagged Ggamma3 did not interact with Gbeta5, CFP-tagged Ggamma3 strongly interacted with YFP-tagged Gbeta5 in FRET studies. Moreover, CFP-Ggamma3 supported Ca(2+) channel inhibition when paired with Gbeta5 or YFP-Gbeta5, indicating a "gain of function" for CFP-Ggamma3. Gbeta5 could also interact with RGS11 and its N-terminal, but not its C-terminal domain. On the other hand, RGS11 did not interact with Gbeta1. These studies demonstrate that the GGL domain-containing N terminus of RGS 11 can directly interact with Gbeta5 in vivo and supports the hypothesis that this interaction may contribute to the specificity of Gbeta5 interactions with cellular effector molecules.
Zhou
Janice Y
JY
Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA.
Toth
Peter T
PT
Miller
Richard J
RJ
D002121:Calcium Channel Blockers / Q000494:pharmacology; D020864:Calcium Channels, N-Type / Q000187:drug effects; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004594:Electrophysiology; D004735:Energy Transfer; D005456:Fluorescent Dyes; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D006801:Humans; D018408:Patch-Clamp Techniques; D020710:RGS Proteins / Q000737:chemistry* / Q000235:genetics* / Q000494:pharmacology; D014162:Transfection
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D018076:DNA, Complementary; D005456:Fluorescent Dyes; C118981:G-protein Beta gamma; C490611:GNB5 protein, human; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D020710:RGS Proteins; C400195:RGS11 protein, human; C485693:Rgs11 protein, mouse; D020962:Heterotrimeric GTP-Binding Proteins