Ezrin-radixin-moesin proteins are regulated by Akt-GSK3β signaling in the rat nucleus accumbens core

The ezrin-radixin-moesin (ERM) proteins are a family of membrane-assodated proteins known to play roles in cell-shape determination as well as in signaling pathways. We have previously shown that amphetamine decreases phosphorylation levels of these proteins in the nucleus accumbens (NAcc), an important neuronal substrate mediating rewarding effects of drugs of abuse. In the present study, we further examined what molecular pathways may be involved in this process. By direct microinjection of LY294002, a PI3 kinase inhibitor, or of S9 peptide, a proposed GSK3 beta activator, into the NAcc core, we found that phosphorylation levels of ERM as well as of GSK3 beta in this site are simultaneously decreased. These results indicate that ERM proteins are under the regulation of Akt-GSK3 beta signaling pathway in the NAcc core. The present findings have a significant implication to a novel signal pathway possibly leading to structural plasticity in relation with drug addiction.