Proteolytic cleavage of the Amyloid protein precursor (APP) gives rise to the
β-Amyloid and Amyloid A4 proteins, which are present in human platelets.
Amyloid deposition is associated with type II diabetes, Down syndrome and
a variety of neurological disorders, including Alzheimer’s disease. The Amyloid
precursor protein (APP) undergoes alternative splicing, resulting in several
isoforms. Proteolytic cleavage of APP leads to the formation of the Amyloid
β/A4 Amyloid protein. This protein is involved in the formation of neurofibrillary
tangles and plaques that characterize the senile plaques of Alzheimer’s
patients. APLP1 (Amyloid precursor-like protein 1) and APLP2 are structurally
similar to APP. Human APLP2 is a membrane-bound sperm protein that contains
a region highly homologous to the transmembrane-cytoplasmic domains
of APP found in brain plaques of Alzheimer’s disease patients.