Structural basis for lysophosphatidylserine recognition by GPR34

Abstract

GPR34 is a recently identified G-protein coupled receptor, which has an immunomodulatory role and recognizes lysophosphatidylserine (LysoPS) as a putative ligand. Here, we report cryo-electron microscopy structures of human GPR34-Gi complex bound with either the LysoPS analogue S3E-LysoPS, which contains an ethoxy group at the sn-1 position, or M1, a derivative of S3E-LysoPS in which oleic acid is substituted with a metabolically stable aromatic fatty acid surrogate. In both structures, the ligand-binding pocket is laterally open toward the membrane, allowing lateral entry of lipidic agonists into the cavity. The amine and carboxylate groups of the serine moiety are recognized by the charged residue cluster, and the aromatic fatty acid surrogate of M1 forms stable hydrophobic interactions with the cavity, thus acting as a superagonist. Molecular dynamics simulations further account for the LysoPS-regioselectivity of GPR34. Thus, using a series of structural and physiological experiments, we provide evidence that chemically unstable 2-acyl LysoPS is the physiological ligand for GPR34, suggesting its short signal duration. Overall, we anticipate the present structures will pave the way for development of novel anticancer drugs that specifically target GPR34.

Selective agonism of GPR34 stimulates microglial uptake and clearance of amyloid β fibrils

“…The development of orally bioavailable GPR34 agonists with improved brain penetrance would enable more comprehensive investigations into the therapeutic potential of GPR34 activation in AD models. In this regard, our recent elucidation of the GPR34-M1 binding structure (19) may facilitate the rational design of novel GPR34 agonists. However, it is also important to consider potential side effects related to GPR34's roles in immune regulation and neuropathic pain (24).…”

“…Together with P2RY10 and GPR174, GPR34 comprises the lysophosphatidylserine (LysoPS) receptor family (14, 15). Uniquely within this receptor family, GPR34 exhibits selectivity for LysoPS species with a fatty acid at the sn -2 position (16–19). While GPR34 is involved in various immunomodulatory functions (20–22), another study highlights its importance in the regulation of phagocytosis in microglia (23).…”

Structural basis for ligand recognition and signaling of the lysophosphatidylserine receptors GPR34 and GPR174

“…In a preprint paper [ 43 ], the authors reported 2 cryo-EM structures of GPR34-Gi complex bound with the LysoPS analogue S3E-LysoPS or its derivate M1. S3E-LysoPS is a sn-3 LysoPS containing an ethoxy group at the sn-1 position, while what we used in our study is sn-1 LysoPS.…”

Optimizing Cryo-EM Structural Analysis of Gi-coupling Receptors via Engineered Gtand Nb35 Application

“…The single-chain variable fragment of mAb16 (scFv16), another remarkable antibody, specifically recognizes the interface between the N-terminal helix of Gαi (αN helix) and Gβ 10 . scFv16 also imparts resistance to GTPγS on the G protein and enhances the requisite features for cryo-EM structural analysis, thereby facilitating structural determination 1,2,[11][12][13][14] . Furthermore, the versatile applicability of scFv16 extends to other G-proteins through substitution with the αN helix of the Gα subunit.…”