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Structural insight into apelin receptor-G protein stoichiometry
Nature Structural & Molecular Biology
|July 11, 2022
Summary
Cryo-electron microscopy revealed the human apelin receptor (APJR) complexed with G proteins in both 2:1 and 1:1 ratios. This stoichiometry influences signaling and pharmacology, highlighting GPCR regulation via oligomerization.
Area of Science:
- Structural biology
- Biochemistry
- Molecular pharmacology
Background:
- Cryo-electron microscopy (cryo-EM) is pivotal for membrane protein structure determination.
- G protein-coupled receptors (GPCRs) are crucial drug targets involved in diverse signaling pathways.
Purpose of the Study:
- To structurally characterize the human apelin receptor (APJR) in complex with a heterotrimeric G protein.
- To investigate the role of APJR stoichiometry in G protein coupling and downstream signaling.
Main Methods:
- Cryo-electron microscopy single-particle analysis.
- Biochemical characterization of APJR-G protein complexes.
Main Results:
- Observed APJR-G protein complexes in both 2:1 and 1:1 stoichiometric ratios.
- Identified structural differences in G protein engagement between dimeric and monomeric APJR.
- Characterized a hydrophobic dimer interface for class A GPCRs.
Conclusions:
- GPCR stoichiometry modulates downstream signaling and pharmacology.
- Oligomerization represents a versatile mechanism for GPCR signaling regulation.
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