Early Onset Alzheimer’s Disease and Oxidative Stress
Figure 2
Human APP gene structure. (a) The APP gene consisting of 18 exons is located on chromosome 21 (21q21.2-3) and is alternatively spliced into several products, named according to their length in amino acids (i.e., APP695, APP714, APP751, APP770, and APP563) that are expressed differentially by tissue type. The region encoding the amyloid sequence comprises part of exons 16 and 17 (red box). (b) APP is a member of a family of conserved type I membrane proteins and consists of a large extracellular domain, a hydrophobic transmembrane domain, and a short cytoplasmic carboxyl terminus. Some isoforms contain a domain homologous to the Kunitz-type serine protease inhibitors (KPI) in the extracellular sequences (pink box). Amyloid sequence contains 40- and 43-amino-acid residues that extend from the ectodomain into the transmembrane domain of the protein. The Aβ sequence lies partially outside the cell membrane (amino acids 1–17 of Aβ) and the some identified mutations in the protein are indicated in bold.
