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Updated: Aug 28, 2025

A Pipeline to Investigate the Structures and Signaling Pathways of Sphingosine 1-Phosphate Receptors
Published on: June 8, 2022
Structural insights into the G protein selectivity revealed by the human EP3-Gi signaling complex
Ryoji Suno1, Yukihiko Sugita2, Kazushi Morimoto3
1Department of Medical Chemistry, Kansai Medical University, Hirakata 573-1010, Japan.
Abstract:
Prostaglandin receptors have been implicated in a wide range of functions, including inflammation, immune response, reproduction, and cancer. Our group has previously determined the crystal structure of the active-like EP3 bound to its endogenous agonist, prostaglandin E2. Here, we present the single-particle cryoelectron microscopy (cryo-EM) structure of the human EP3-Gi signaling complex at a resolution of 3.4 Å. The structure reveals the binding mode of Gi to EP3 and the structural changes induced in EP3 by Gi binding. In addition, we compare the structure of the EP3-Gi complex with other subtypes of prostaglandin receptors (EP2 and EP4) bound to Gs that have been previously reported and examine the differences in amino acid composition at the receptor-G protein interface. Mutational analysis reveals that the selectivity of the G protein depends on specific amino acid residues in the second intracellular loop and TM5.
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