Sustained Activity of Metabotropic Glutamate Receptor: Homer, Arrestin, and Beyond

Figure 1

Proposed model of sustained mGlu activation. β-Arrestin binding to the mGlu internalizes the receptor. With stable binding to the mGlu C-terminal, β-arrestin mediates receptor internalization and activates ERK1/2 MAPK, but does not induce desensitization of G protein signaling. In this condition, the β-arrestin tightly binds only to the C-terminal tail but not to the transmembrane region, and thus the G protein can simultaneously bind to the transmembrane core of the receptor. The downstream pathways are activated without interfering with each other. The convergence of the downstream pathways on common effectors and their reciprocal interactions are omitted in this figure.