Download MendeleyStructural basis for lysophosphatidic acid recognition and atypical G alpha q coupling by LPAR5.
Li, X., Wang, K., Xing, Z., Zhang, M., Hu, W., Yuan, Q., Xu, H.E., Zhao, L.H.(2026) Proc Natl Acad Sci U S A 123
- PubMed: 42313925 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1073/pnas.2537482123
- Primary Citation Related Structures:
20ZX - PubMed Abstract:
Lysophosphatidic acid receptor 5 (LPAR5) is a non-endothelial differentiation gene class A G protein-coupled receptor that regulates neuropathic pain, itch, and cancer progression through coupling to G proteins. Here, we report the cryo-EM structure of LPAR5 bound to 1-oleoyl-lysophosphatidic acid (LPA) in complex with G q at 2.96 Å resolution, revealing a distinct mode of receptor activation and G protein coupling. The phosphate headgroup of LPA forms extensive polar interactions with residues from extracellular loop 2 and transmembrane helices TM5-TM7, while the lipid tail inserts into a deep hydrophobic cavity formed by TM3-TM5. Site-directed mutagenesis confirms the functional importance of these interactions. Remarkably, LPAR5 exhibits a noncanonical G protein coupling mode. Unlike previously reported GPCR-G protein structures in which the Gα C-terminal α5 helix ("wavy hook") primarily engages TM6, the wavy hook in LPAR5 is positioned toward the intracellular loop 1-helix 8 interface. This configuration is associated with limited TM6 outward displacement and modest rearrangement at the toggle-switch position (6.48). The resulting interface is stabilized by receptor-specific interactions and supported by functional data. Together, these findings reveal an alternative mode of GPCR-G protein coupling and highlight the structural plasticity underlying signaling specificity in LPA receptors.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
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