Structural insight into the recognition of pathogen-derived phosphoglycolipids by C-type lectin receptor DCAR.Omahdi, Z., Horikawa, Y., Nagae, M., Toyonaga, K., Imamura, A., Takato, K., Teramoto, T., Ishida, H., Kakuta, Y., Yamasaki, S.
(2020) J.Biol.Chem. --: --
- PubMed: 32139512
- DOI: 10.1074/jbc.RA120.012491
- Primary Citation of Related Structures:
- PubMed Abstract:
The C-type lectin receptors (CLRs) form a family of pattern recognition receptors (PRRs) that recognize numerous pathogens, such as bacteria and fungi, and trigger innate immune responses. The extracellular carbohydrate recognition domain (CRD) of CL ...
The C-type lectin receptors (CLRs) form a family of pattern recognition receptors (PRRs) that recognize numerous pathogens, such as bacteria and fungi, and trigger innate immune responses. The extracellular carbohydrate recognition domain (CRD) of CLRs forms a globular structure that can coordinate a Ca 2+ ion, allowing receptor interactions with sugar-containing ligands. Although well conserved, the CRD fold can also display differences that directly affect the specificity of the receptors for their ligands. Here, we report crystal structures at 1.8-2.3 Å resolutions of the CRD of murine d endritic c ell-immuno a ctivating r eceptor (DCAR/ Clec4b1 ), the only CLR that binds phosphoglycolipids such as acylated phosphatidyl-myo-inositol mannosides (AcPIMs) of mycobacteria. Using mutagenesis analysis, we identified critical residues, Ala136 and Gln198, on the surface surrounding the ligand-binding site of DCAR, as well as an atypical Ca 2+ -binding motif (Glu-Pro-Ser/EPS 168-170 ). By chemically synthesizing a water-soluble ligand analog, inositol-monophosphate di-mannose (IPM2), we confirmed the direct interaction of DCAR with the polar moiety of AcPIMs by biolayer interferometry and co-crystallization approaches. We also observed a hydrophobic groove extending from the ligand-binding site that is in a suitable position to interact with the lipid portion of whole AcPIMs. These results suggest that the hydroxyl group-binding ability and hydrophobic groove of DCAR mediate its specific binding to pathogen-derived phosphoglycolipids such as mycobacterial AcPIMs.
Research Institute for Microbial Diseases, Osaka University, Japan.,Department of Pharmaceutical Sciences, The University of Tokyo, Japan.,Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Japan.,Laboratory of Structural Biology, Graduate School of System Life Sciences, Kyushu University, Japan.,Gifu University.,Department of Applied Bioorganic Chemistry, Faculty of Applied Biological Sciences, Gifu University, Japan.,Kyushu University, Japan.