Amyloid beta A4 protein （APP） functions as a cell surface receptor and transmembrane precursor protein which is cleaved by secretases to form a number of peptides. A number of these peptides are secreted and can bind to the acetyltransferase complex APBB1/TIP60 to stimulate transcriptional activation， whereas others form the protein basis of the amyloid plaques found in the brains of patients with Alzheimer disease. APP gene mutations are implicated in autosomal dominant Alzheimer disease and cerebroarterial amyloidosis （cerebral amyloid angiopathy）.
