This study is the initial phase in a project which seeks to understand the molecular aging of brian receptor proteins. Dr. Duffy has chosen a receptor protein recently reported to be the precursor to the amyloid deposits found in aging mammalian brains. Preliminary studies by others indicate that the gene is highly conserved across species and appears to be expressed in many different cell types, including neurons. In this initial phase, Dr. Duffy will survey a variety of cell types, including endothelial cells, glial, neurons and fibroblasts to see if the protein is expressed in sufficient quantities for biochemical studies. Quantitation will be performed by isolating the protein using modern FPLC procedures devised for membrane proteins. Purification of this receptor protein will be followed using antibodies raised to various regions of the human protein, based on the DNA-derived sequence. Dr. Duffy will supplement these antibodies by the production of monoclonal antibodies to the purified receptor. While these studies to find a suitable model system are in progress, Dr. Duffy will study the necessary elements of amyloid formation using a series of peptide analogues to the 40 amino acid amyloid fragment. The effect of different amino acids on the structure of amyloid will be monitored using EM, x-ray and NMR methodologies.
