Overview

My research program is focused on elucidating the structural determinants of apolipoprotein (apo) E ligand binding to the low-density lipoprotein receptor (LDLR). Using an unique protein engineering approach termed expressed protein ligation (EPL), I have created a segmental stable isotope-labeled apoE amino-terminus (NT) for study of apoE lipid-induced conformational change using nuclear magnetic resonance (NMR) spectroscopy. With this technique, I hope to characterize the detailed molecular adaptations within apoE that are required for functional interaction with the LDLR.

Gene knock-out and transgenic experiments in mice have revealed that apoE is critically involved in the homeostatic maintenance of blood cholesterol levels via an interaction with members of the LDLR family. Additional genetic and structural work has shown that apoE and LDLR family members are also centrally involved in the physiology of neuronal functioning and the pathophysiology of Alzheimer’s disease. In both the brain and periphery, apoE functions as a carrier of cholesterol and lipid soluble metabolites that are taken up by cells of the vasculature and central nervous system via receptor mediated endocytosis. Although the lipid-free structure of the apoE NT has been structurally well characterized, the lipid induced conformational change in the NT domain that confers LDLR binding activity is significantly less defined. I am currently working to characterize the lipid associated conformational of the apoE NT domain that confers LDLR binding activity using a combination of EPL and heteronuclear multidimensional NMR spectroscopy.
The objective of this research is to better understand the process of ligand-dependent LDLR functioning, with the aim of providing further insight into the receptor mediated uptake of lipoprotein-associated metabolites that is central to both normal physiological functioning and the pathophysiology of Alzheimer’s and cardiovascular disease.

revised: Tuesday, June 16, 2009 4:57 PM