Characterization of a membrane bound form of the amyloid protein precursor (APP) of alzheimer’s disease

Abstract

βA4 protein (~4 kDa) is deposited in the brain in Alzheimer’s Disease (AD), and is likely due to aberrent processing of a membrane-associated amyloid precursor protein (APP). Normal processing of the membrane-associated APP generates a truncated form which does not contain the full βA4 sequence. The possible existance of an APP isoform with intact transmembrane and carboxyl terminus domain in the circulation is of interest, as it may contribute to βA4 amyloidogenesis. We have previously shown that full length APP is present in the platelet releasate. [A. I. Bush et al, (1990) J. Biol. Chem. 265, 15977]. In this study, we further characterized this form by using platelet membrane vesicles. Us..