Binding sites of amyloid beta-peptide in cell plasma membrane and implications for Alzheimer's disease

The binding of amyloid beta peptides (Abeta) to plasma membranes appears to be a promising point of intervention in the events leading to the development of Alzheimer's disease (AD). This binding has been studied as regards the direct toxicity of Abeta on neurons, and the activation of a local inflammation phase involving microglia. By virtue of its structure, Abeta is able to bind to a variety of biomolecules, including lipids, proteoglycans and proteins. This review focuses on the membrane proteins that can mediate the interaction between Abeta and the plasma membranes in AD. On neurons, these are APP (amyloid precursor protein), the NMDA-R (N-methyl-D-aspartate receptor), integrins, the alpha7nicotinic acetylcholine receptor (alpha7nAChR), the P75 neurotrophin receptor (P75NTR) and the CLAC-P/collagen type XXV (collagen-like Alzheimer amyloid plaque component precursor/collagen XXV). On glial cells, FPRL1 (formyl peptide receptor-like 1), the scavenger receptors A, BI (SR-A, SR-BI) and CD36, a complex involving CD36, alpha(6)beta(1)-integrin and CD47, and heparan sulfate proteoglycans have been reported to bind Abeta. It should be noted that integrins, RAGE (receptor for advanced glycosylation end-products), the Serpin-enzyme complex receptor (SEC-R) and the insulin receptor can bind Abeta and are present on neurons and on glial cells. After a presentation of the structure and the function of each of these proteins, the method used to prove their binding to Abeta is described, and the implication of this binding in AD is discussed. Finally, it is underlined that multireceptor complexes containing integrins may be involved in this interaction.