Figure 10.

Model for optineurin and Rab8-mediated attenuation of mGluR1a signaling and endocytosis. Agonist activation of mGluR1a results in the recruitment of Rab8, which interacts with the mGluR1a, but not mGluR1b C-terminal tail. Rab8 functions in concert with optineurin to attenuate mGluR1a G-protein coupling, resulting in diminished IP formation and impaired release of Ca²⁺ from intracellular stores. Rab8, but not optineurin, interactions with mGluR1a impair mGluR1a endocytosis and result in an increase in cell surface mGluR1a expression. Optn, Optineurin.