Alterations of some membrane transport proteins in Alzheimer's disease: Role of amyloid β-peptide

Alzheimer's disease (AD) is the most common neurodegenerative disease characterized clinically by progressive memory loss and decline in cognitive abilities and characterized pathologically by the presence of two types of abnormal deposits, i.e., senile plaques (SP) and neurofibrillary tangles (NFT), and by extensive synapse and neuronal loss. SP are composed of fibrillar amyloid β-peptide (Aβ) surrounded by dystrophic neurites. Recent studies suggest two prospective mechanisms for Aβ-associated membrane dysfunction and subsequent neurotoxicity. One suggests that Aβ oligomers can form heterogeneous ion-channels in the cell membrane leading to cellular degeneration, while the second suggests insertion of Aβ oligomers in membrane lipid bilayers could induce the dysfunction of ion-channels or pumps by binding to or inducing oxidative modification of membrane proteins. In this review, we discuss the effects of Aβ on membrane proteins that are involved in cholinergic and glutamatergic pathways, and some ion-channels.