APP(redirected from preA4)
Also found in: Dictionary, Financial, Encyclopedia.
APPamyloid precursor protein.
amyloid precursor protein
amyloid precursor protein (APP)
a large transmembrane glycoprotein expressed on the cell surface and of uncertain function; it may be cleaved on the cell surface to a soluble form. Alternatively, cleavage may follow endocytosis and in some cases then yields 40 to 43 abnormal amino acid peptides, which aggregate to form Ab amyloid, associated with Alzheimer's disease.
APPA gene on chromosome 21q21.3 that encodes a cell surface receptor and transmembrane precursor protein which is cleaved by secretases to form various peptides.
APP mutations are implicated in autosomal dominant Alzheimer’s disease and cerebroarterial amyloidosis (cerebral amyloid angiopathy).