Fig. 5: Structural changes in the intracellular side of TM2 upon CB1 activation.

a Concerted movement of F237^4.46 and F155^2.24 upon activation of CB1 from inactive (inward, gray) to active (outward, blue) state. b The residue at position 4.46 in CB2 is a Leu and does not undergo movement upon activation. c NanoBiT-G-protein dissociation assay shows unchanged CP (CP 55940) response upon ORG (Org 27569) treatment in CB2. (mean ± SEM, n = 4 independent experiments). d GTP turnover assay showing reduced turnover in the presence of ORG (Org 27569) with G_i1. (mean ± SD, p < 0.0001**** and p = 0.0010***, unpaired t-test (two-tailed), n = 3 independent experiments). e Structural rearrangement in F237^4.46 and F155^2.42 in ORG (Org 27569) (PDB: 6KQI, green) bound structure compared to active AMG315-bound (blue) and inactive (gray) structures. Residues F237^4.46 and F155^2.42 are inward towards the receptor core in the ORG-bound and inactive structures compared to AMG315-bound structure where they are outwards.