Select G-Protein-Coupled Receptors Modulate Agonist-Induced Signaling via a ROCK, LIMK, and β-Arrestin 1 Pathway

• δOR activation of the ROCK-LIMK-cofilin pathway rapidly regulates δOR function
• β-arrestin1 deletion increases, whereas ROCK inhibition suppresses, δOR function
• Activation of this pathway can alter δOR-dependent behaviors
• ORL1 is similarly regulated by this ROCK-β-arrestin 1 pathway

SummaryG-protein-coupled receptors (GPCRs) are typically present in a basal, inactive state but, when bound to an agonist, activate downstream signaling cascades. In studying arrestin regulation of opioid receptors in dorsal root ganglia (DRG) neurons, we find that agonists of delta opioid receptors (δORs) activate cofilin through Rho-associated coiled-coil-containing protein kinase (ROCK), LIM domain kinase (LIMK), and β-arrestin 1 (β-arr1) to regulate actin polymerization. This controls receptor function, as assessed by agonist-induced inhibition of voltage-dependent Ca2+ channels in DRGs. Agonists of opioid-receptor-like receptors (ORL1) similarly influence the function of this receptor through ROCK, LIMK, and β-arr1. Functional evidence of this cascade was demonstrated in vivo, where the behavioral effects of δOR or ORL1 agonists were enhanced in the absence of β-arr1 or prevented by inhibiting ROCK. This pathway allows δOR and ORL1 agonists to rapidly regulate receptor function.

Graphical AbstractFigure optionsDownload as PowerPoint slide