Structural basis of lysophosphatidylserine receptor GPR174 ligand recognition and activation.

Liang, Jiale; Inoue, Asuka; Ikuta, Tatsuya; Xia, Ruixue; Wang, Na; Kawakami, Kouki; Xu, Zhenmei; Qian, Yu et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Lysophosphatidylserine (LysoPS) is a lipid mediator that induces multiple cellular responses through binding to GPR174. Here, we present the cryo-electron microscopy (cryo-EM) structure of LysoPS-bound human GPR174 in complex with G<sub>s</sub> protein. The structure reveals a ligand recognition mode, including the negatively charged head group of LysoPS forms extensive polar interactions with surrounding key residues of the ligand binding pocket, and the L-serine moiety buries deeply into a positive charged cavity in the pocket. In addition, the structure unveils a partially open pocket on transmembrane domain helix (TM) 4 and 5 for a lateral entry of ligand. Finally, the structure reveals a G<sub>s</sub> engaging mode featured by a deep insertion of a helix 5 (αH5) and extensive polar interactions between receptor and αH5. Taken together, the information revealed by our structural study provides a framework for understanding LysoPS signaling and a rational basis for designing LysoPS receptor-targeting drugs.

Medical subject headings