Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Natural Science Foundation of China (NSFC)
Primary Citation of Related Structures:   6PB0, 6PB1
PubMed Abstract: 
Corticotropin-releasing factor (CRF) and the three related peptides urocortins 1-3 (UCN1-UCN3) are endocrine hormones that control the stress responses by activating CRF1R and CRF2R, two members of class B G-protein-coupled receptors (GPCRs). Here, we present two cryoelectron microscopy (cryo-EM) structures of UCN1-bound CRF1R and CRF2R with the stimulatory G protein ...
Corticotropin-releasing factor (CRF) and the three related peptides urocortins 1-3 (UCN1-UCN3) are endocrine hormones that control the stress responses by activating CRF1R and CRF2R, two members of class B G-protein-coupled receptors (GPCRs). Here, we present two cryoelectron microscopy (cryo-EM) structures of UCN1-bound CRF1R and CRF2R with the stimulatory G protein. In both structures, UCN1 adopts a single straight helix with its N terminus dipped into the receptor transmembrane bundle. Although the peptide-binding residues in CRF1R and CRF2R are different from other members of class B GPCRs, the residues involved in receptor activation and G protein coupling are conserved. In addition, both structures reveal bound cholesterol molecules to the receptor transmembrane helices. Our structures define the basis of ligand-binding specificity in the CRF receptor-hormone system, establish a common mechanism of class B GPCR activation and G protein coupling, and provide a paradigm for studying membrane protein-lipid interactions for class B GPCRs.
Organizational Affiliation: 
The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: eric.xu@simm.ac.cn.
Guanine nucleotide-binding protein G(s) subunit alpha isoforms short,Guanine nucleotide-binding protein G(i) subunit alpha-1,Guanine nucleotide-binding protein G(s) subunit alpha isoforms short