Stabilized Huntingtin Oligomers Used to Determine Mechanism of Lipid Membrane Binding

Emily Donley*and Justin Legleiter

C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506

Presentation Category: Biological & Biochemical Sciences (Poster Presentation #100)

Student’s Major: Biochemistry

There are several neurodegenerative diseases classified as protein-misfolding diseases, where rearrangement of a protein’s conformation leads to aggregation. These include Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. Huntington’s disease is caused by a polyglutamine expansion in the huntingtin protein (htt), which allows htt to aggregate into different forms. These aggregates can damage a variety of membranes within cells. The first 17 amino acids of htt (Nt17) affect both aggregate formation and lipid membrane binding. Therefore, a possible method of treating Huntington’s disease involves blocking htt from binding to the lipid membranes of cells. Preliminary data shows that the oligomer state of aggregation has the highest affinity for membranes, and when the lysine residues of the oligomers were crosslinked with DFDNB, they were stabilized, not forming further aggregates and losing their membrane activity. Oligomer-stabilizing htt mimic peptides with the lysine residues mutated to remove their positive charge are now being used to test whether this loss of membrane activity is due to changes in conformational flexibility or charge of the lysine residues. Preliminary results show that oligomers formed with these peptides retain their membrane interaction in a PDA assay, and atomic force microscopy showed that they are stable for up to eight hours relative to a control. This suggests that the loss of membrane activity in previous experiments is due to conformational changes, not changes in the lysine residues’ charge.

Funding:

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course