Function of Appican and Sulfation Pattern in AD Brains

The amyloid precursor protein (APP) is produced in different forms (called isoforms), and one of these isoforms has been found by Dr. Shioi to be the core protein of a complex type of protein called a chondroitin sulfate proteoglycan (a protein that contains sulfur and sugar molecules). Dr. Shioi calls this APP-containing protein “appican.” Appican is found in brain tissue and is produced by a type of brain cell (called an astrocyte) in cell culture, but non-neuronal cell lines produce little or no appican. Recent evidence suggests that chondroitin sulfate proteoglycans are involved in neuronal growth and development. Dr. Shioi is examining the possible role of appican in normal brain function and whether this role is changed in Alzheimer’s disease (AD). The results of these experiments could identify a new role for the APP protein in AD.