Structural basis of oligomerization-modulated activation and autoinhibition of orphan receptor GPR3 by Hao Chang & Xiaoting Li & Hongqing Tu & Lijie Wu & Yanan Yu & Junlin Liu & Na Chen & Wei L. Shen & Tian Hua ISBN 101016/JCELREP2025115478 instant download

Structural basis of oligomerization-modulated activation and autoinhibition of orphan receptor GPR3 by Hao Chang & Xiaoting Li & Hongqing Tu & Lijie Wu & Yanan Yu & Junlin Liu & Na Chen & Wei L. Shen & Tian Hua ISBN 101016/JCELREP2025115478 instant download

SUMMARYG protein-coupled receptor 3 (GPR3) is a class A orphan receptor characterized by high constitutive activityin the Gs signaling pathway. GPR3 has been implicated in Alzheimer’s disease and the regulation of thermogenesis in human adipocytes, yet the molecular mechanisms underlying its self-activation and potentialendogenous modulators remain unclear. In this study, we present cryo-electron microscopy (cryo-EM) structures of GPR3 in different oligomerization states, both in the absence and presence of G protein. Notably, inaddition to the monomeric form of GPR3, our findings reveal a functional GPR3 dimer with an extensive dimerinterface—a feature rarely observed in class A GPCRs. Moreover, oligomerization appears to be linked to aunique autoinhibition mechanism involving intracellular loops, which may regulate GPR3 signaling. Collectively, these results provide new insights into the oligomerization-modulated activation of orphan GPCRs,advancing our understanding of their signaling properties.