PMID: 24889612 , Related PDB ids: 3WUZ, 3WV0

Authors:

Kuroki K, Wang J, Ose T, Yamaguchi M, Tabata S, Maita N, Nakamura S, Kajikawa M, Kogure A, Satoh T, Arase H, Maenaka K

Title:

Structural basis for simultaneous recognition of an O-glycan and its attached peptide of mucin family by immune receptor PILRalpha.

Journal:

Proc Natl Acad Sci U S A. 2014 Jun 17;111(24):8877-82. doi:, 10.1073/pnas.1324105111. Epub 2014 Jun 2.

Abstract:

Paired Ig-like type 2 receptor alpha (PILRalpha) recognizes a wide range of O-glycosylated mucin and related proteins to regulate broad immune responses. However, the molecular characteristics of these recognitions are largely unknown. Here we show that sialylated O-linked sugar T antigen (sTn) and its attached peptide region are both required for ligand recognition by PILRalpha. Furthermore, we determined the crystal structures of PILRalpha and its complex with an sTn and its attached peptide region. The structures show that PILRalpha exhibits large conformational change to recognize simultaneously both the sTn O-glycan and the compact peptide structure constrained by proline residues. Binding and functional assays support this binding mode. These findings provide significant insight into the binding motif and molecular mechanism (which is distinct from sugar-recognition receptors) by which O-glycosylated mucin proteins with sTn modifications are recognized in the immune system as well as during viral entry.