Opioid receptor random mutagenesis reveals a mechanism for G protein-coupled receptor activation

Fabien M. Décaillot (1) , Katia Befort (1) , Dominique Filliol (1) , Shiyi Yue , Philippe Walker , Brigitte L. Kieffer (1)

1 IGBMC - Institut de génétique et biologie moléculaire et cellulaire

The high resolution structure of rhodopsin has greatly enhanced current understanding of G protein-coupled receptor (GPCR) structure in the off-state, but the activation process remains to be clarified. We investigated molecular mechanisms of delta-opioid receptor activation without a preconceived structural hypothesis. Using random mutagenesis of the entire receptor, we identified 30 activating point mutations. Three-dimensional modeling revealed an activation path originating from the third extracellular loop and propagating through tightly packed helices III, VI and VII down to a VI-VII cytoplasmic switch. N- and C-terminal determinants also influence receptor activity. Findings for this therapeutically important receptor may apply to other GPCRs that respond to diffusible ligands.

Domaines: Biochimie, Biologie Moléculaire

Fabien M. Décaillot, Katia Befort, Dominique Filliol, Shiyi Yue, Philippe Walker, et al.. Opioid receptor random mutagenesis reveals a mechanism for G protein-coupled receptor activation. Nature Structural Biology, 2003, 10 (8), pp.629-636. ⟨10.1038/nsb950⟩. ⟨hal-04143718⟩