PROJECT SUMMARY Glycoproteins and proteoglycans are important protein glycoconjugates in the cell. They can control many biological events, such as growth factor signaling, cell adhesion, and differentiation, to impact cancer biology, development, and immunity. While vital to human health and physiology, we currently do not have a comprehensive molecular understanding of how these molecules orchestrate their functions. Many techniques study these molecules in isolation – focusing on only the protein or glycan component alone. This current approach severely underappreciates the structural diversity of protein glycoconjugates, and it has left us with a narrowed understanding of how protein glycoforms can differentially regulate biology. Furthermore, it has impeded pathways to use glycoform-dependent interactions for drug discovery. Our research program integrates techniques in chemical biology, molecular biology, and protein engineering, in order to address these gaps. In this application, we describe our plans to create defined semi-synthetic glycoproteins and proteoglycans, and to use these materials to study their interactions in live cells. Identifying the glycoproteins associated with glycan-binding proteins allows the use of targeted genetic approaches to study their functional contributions. The insights developed from these studies will create an opportunity to discover small molecules that can selectively modulate glycan-binding protein and glycoprotein interactions in order to regulate important biological events.

PROJECT NARRATIVE Our current understanding of how glycans regulate biological events is limited, marred by the technical challenge of analyzing protein glycoconjugate structure and interactions. Our research seeks to bridge the gap between proteins and glycans by using chemical biology approaches. This program can illuminate the nature and behavior of protein glycoconjugates in living cells in the short term, and it can pave the way towards biomedical interventions to promote health in the long term.