Structural insights into the ligand modulation of MRGPRX4 conformational plasticity.
Zhang, M., Wang, Y., Huang, Y., Liang, Y., Chen, P., Ji, Z., Song, M., Chen, H., Wang, C., Cao, C.(2026) Cell Discov 12
- PubMed: 42869878 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1038/s41421-026-00929-x
- Primary Citation Related Structures: 
23CS, 23CU, 23CV, 23CW, 23CX, 23CY - PubMed Abstract: 
Chronic pruritus is a debilitating condition with limited treatment options, particularly in cholestatic liver diseases, where bile acid dysregulation is a known trigger. Although Mas-related G protein-coupled receptor X4 (MRGPRX4) has recently been identified as a key mediator of bile acid-induced pruritus, the structural mechanisms underlying its inhibition remain poorly understood, hindering the development of therapeutic antagonists. Here, we report the cryo-electron microscopy structures of MRGPRX4 in three distinct states: agonist-bound state, antagonist-bound state, and apo state. Our structures reveal a previously unrecognized antagonist-binding site that is structurally distinct from those engaged by agonists. Complementary functional assays and molecular dynamics simulations further demonstrate that the extracellular pocket of MRGPRX4 undergoes pronounced ligand-dependent conformational rearrangements upon binding to both the agonist and the antagonist. Collectively, these findings elucidate the conformational plasticity underlying MRGPRX4 activity modulation and establish a structural framework for the rational design of MRGPRX4 antagonists that target chronic pruritus.
- Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
Organizational Affiliation: 

