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Author Spotlight: Exploring Cellular Processes by Modeling Ligands in Cryo-EM Maps
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Published on: July 19, 2024

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GPR174 Antagonism: Structure, Function, and Dynamics

Vijay Kumar Bhardwaj, Alemayehu Gorfe

    Biorxiv : the Preprint Server for Biology
    |September 26, 2025
    PubMed

    Insights

    GPR174, a receptor implicated in cancer immunotherapy resistance, is inactivated by the antagonist mPS, unlike its activator lysophosphatidylserine (LysoPS). This provides a basis for developing new cancer therapies.

    Area of Science:

    • Immunology
    • Pharmacology
    • Structural Biology

    Background:

    • GPR174 is an immune-restricted G-protein-coupled receptor (GPCR) activated by lysophosphatidylserine (LysoPS).
    • Elevated LysoPS in tumors can lead to immunosuppression and resistance to cancer immunotherapies.
    • Understanding GPR174's interaction with ligands is crucial for developing targeted cancer treatments.

    Purpose of the Study:

    • To investigate the molecular mechanisms underlying GPR174 activation and antagonism.
    • To compare the binding modes and conformational dynamics of GPR174 with its activator (LysoPS) and an antagonist (mPS).
    • To provide a structural basis for designing novel GPR174-targeted cancer immunotherapies.

    Main Methods:

    • Molecular modeling of GPR174 bound to mPS.
    • Extensive molecular dynamics (MD) simulations in a heterogeneous lipid bilayer.
    • Parallel simulations of LysoPS-bound GPR174.
    • Network analysis and protein-lipid interaction analysis.

    Main Results:

    • mPS binding inactivated GPR174, reducing conformational dynamics and stabilizing interactions with transmembrane helix 1.
    • LysoPS binding induced greater conformational flexibility, multiple binding poses, and transient membrane interactions.
    • LysoPS engaged conserved activation motifs (PIF, DRY, N/DPxxY) to couple ligand binding to the G-protein interface, while mPS disrupted these pathways.
    • Membrane lipids like PIP2 were shown to modulate ligand dynamics and receptor conformational states.

    Conclusions:

    • Distinct ligand-specific mechanisms govern GPR174 modulation by LysoPS and mPS.
    • mPS acts as an effective antagonist by disrupting key activation pathways within GPR174.
    • These findings offer a framework for the rational design of selective GPR174 antagonists for cancer immunotherapy.

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