Human brain synembryn interacts with Gsα and Gqα and is translocated to the plasma membrane in response to isoproterenol and carbachol

Abstract

Heterotrimeric G-proteins transduce signals from heptahelical transmembrane receptors to different effector systems, regulating diverse complex intracellular pathways and functions. In brain, facilitation of depolarization-induced neurotransmitter release for synaptic transmission is mediated by Gsα and Gqα. To identify effectors for Gα-proteins, we performed a yeast two-hybrid screening of a human brain cDNA library, using the human Gαs protein as a bait. We identified a protein member of the synembryn family as one of the interacting proteins. Extending the study to other Gα subunits, we found that Gqα also interacts with synembryn, and these interactions were confirmed by in vitro pull down studies and by in vivo confocal laser microscopy analysis. Furthermore, synembryn was shown to translocate to the plasma membrane in response to carbachol and isoproterenol. This study supports recent findings in C. elegans where, through genetic studies, synembryn was shown to act together with Gqα regulating neuronal transmitter release. Based on these observations, we propose that synembryn is playing a similar role in human neuronal cells. © 2003 Wiley-Liss, Inc.