Structural basis of CD97 activation and G-protein coupling

Heterogeneity of Tethered Agonist Signaling in Adhesion G Protein-Coupled Receptors

“…Our scanning mutagenesis showed that signaling from ADGRE5 was intolerant of either alanine or lysine substitution at both F533 (P3') and L536 (P6') (Fig. S3A), consistent with the known importance of these positions for signaling by other aGPCRs and the deep burial of these TA positions in active state aGPCR structures 26,27,[34][35][36][37][38] . The observed effects of other stalk sequence mutations aligned with a homology model of the ADGRE5 CTF (Fig.…”

“…Active state structures of CTFs of aGPCRs show that the TA is positioned in a conformation with an exit vector compatible with an N-terminal fusion extending into the extracellular space (Fig. S1A) [34][35][36][37][38] . We postulated that insertion of a stable N-terminal fusion protein would permit TA-dependent signaling and reduce variation in steady-state protein abundance among different aGPCRs and their variants, enabling the measurement of TAdependent and TA-independent signaling activity for each aGPCR using a single expression cassette.…”

“…An atomic-level view of tethered agonism in aGPCRs has emerged from single particle cryo-electron microscopy (cryo-EM) studies of seven CTFs from different aGPCRs in G proteinbound states [34][35][36][37][38] . For these aGPCRs, the structural studies define a conserved binding pose of the TA in the orthosteric site, which facilitate transition of the GPCR to an active, G protein-bound state.…”