James Paulson headshot

James Paulson, PhD
Co-chair, Molecular Medicine

Carbohydrate binding proteins are increasingly recognized to mediate key aspects of cell trafficking and cell signaling in the immune system. At least three families of carbohydrate binding proteins are known to mediate cellular communication among leukocytes. The siglec family now has thirteen members which are expressed on the surface of various white blood cells (e.g. B cells, NK cells, eosinophils, monocytes etc.), and all recognize sialic acid (NeuAc) containing carbohydrate ligands. The best understood for its function is CD22 (siglec-2), which is known to be a negative regulator of B cell receptor signaling. The carbohydrate ligand of CD22 is the sequence NeuAca2,6Gal on N-linked oligosaccharides of glycoproteins. It is required for normal CD22 function since its absence in mutant mice results in marked immuno-suppression in response to vaccination. The goal of the Paulson laboratory is to elucidate the roles of siglec receptors in immune function, and to define biochemical basis for how the interaction with their carbohydrate ligands modulate their function.