Amyloid precursor proteins (APPs) are members of a large family of 70 kDa transmembrane glycoproteins that are found in a wide range of tissues. APP is expressed in the brain. It is located on human chromosome 21. APPs have three main isoforms, namely, APP695, APP751 and APP770, that are derived from alternative splicing events in cells.
Biochem/physiol Actions
The β-amyloid precursor protein (APP) is cleaved sequentially by the proteolytic enzymes β-secretase (BACE1) and γ-secretase to produce β-amyloid (Aβ) peptides with the Aβ1-42 and the Aβ1-40 forms being the most prevalent. Secreted Aβ peptides are degraded either via a re-uptake mechanism followed by endosomal degradation, or by an extracellular insulin degrading enzyme. Extracellular accumulation of Aβ leads to the formation of aggregates, fibrils and eventually amyloid deposits called neuritic plaques, which is the hallmark of Alzheimer′s disease (AD).Rabbit Anti-β-Amyloid Protein (1-40) antibody does not stain control sections of normal brain tissues.
