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

Figure 2

Feedback modulation of mGlu activity by ERK1/2. Stable binding of β-arrestin to the receptor upregulates ERK1/2 activation, whereas transient binding of β-arrestin downregulates it. The activated ERK1/2 preferentially phosphorylates receptor-bound β-arrestin and regulates its function. In addition, the activated ERK1/2 phosphorylates the Homer binding site of mGlus C-terminal. These feedback mechanisms might play a role in keeping the mGlu persistently active.