A Platform of C-type Lectin-like Receptor CLEC-2 for Binding O-Glycosylated Podoplanin and Nonglycosylated Rhodocytin

Podoplanin is a transmembrane O-glycoprotein that binds to C-type lectin-like receptor 2 (CLEC-2). The O-glycan-dependent interaction seems to play crucial roles in various biological processes, such as platelet aggregation. Rhodocytin, a snake venom, also binds to CLEC-2 and aggregates platelets in a glycan-independent manner. To elucidate the structural basis of the glycan-dependent and independent interactions, we performed comparative crystallographic studies of podoplanin and rhodocytin in complex with CLEC-2. Both podoplanin and rhodocytin bind to the noncanonical “side” face of CLEC-2. There is a common interaction mode between consecutive acidic residues on the ligands and the same arginine residues on CLEC-2. Other interactions are ligand-specific. Carboxyl groups from the sialic acid residue on podoplanin and from the C terminus of the rhodocytin α subunit interact differently at this “second” binding site on CLEC-2. The unique and versatile binding modes open a way to understand the functional consequences of CLEC-2-ligand interactions. [Display omitted] •CLEC-2 recognizes both sialylated O-glycan and the adjoining polypeptide of podoplanin•CLEC-2 simultaneously binds to the C and N termini of rhodocytin•CLEC-2 utilizes its noncanonical side face for binding to podoplanin and rhodocytin•CLEC-2 attains versatile electrostatic interactions toward different ligands CLEC-2 is the receptor for the snake venom toxin rhodocytin and a glycoprotein, podoplanin. Nagae et al. reveal the crystal structures of CLEC-2 complexed with an O-glycosylated podoplanin peptide or nonglycosylated rhodocytin, elucidating the glycan-dependent and glycan-independent interactions.