Figure 2.

Synthetic glycopolypeptides bearing high-affinity Siglec-9 ligands engage Siglec-9 and induce clustering and signaling. (a) Membrane-anchored, cis binding glycopolypeptide 1 (pS9L) induces Siglec-9 signaling, while a soluble control polypeptide 2 (pS9L-sol) or a nonbinding but membrane-anchored control polypeptide 3 (pLac) does not. (b) Structures of the polypeptides pS9L, pS9L-sol, and pLac. Polypeptides are all based on an O-lactosyl poly serine-co-alanine scaffold and in some cases bear terminal Siglec-9-binding sialic acid analogues and/or C-terminal membrane-anchoring lipids.