BACE1 interacts with lipid raft proteins.

A neuropathological hallmark of Alzheimer's disease is the presence of amyloid plaques in the brain. Amyloid-beta peptide (Abeta) is the major constituent of the plaques and is generated by proteolytic cleavages of amyloid precursor protein (APP) by beta- and gamma-secretases. Growing evidence shows that lipid rafts are critically involved in regulating the Abeta generation. In support of this, APP, Abeta, and presenilins have been found in lipid rafts. Although cholesterol plays a crucial role in maintaining lipid rafts, functions of other components in the generation of Abeta are unknown. Caveolins (CAVs) and flotillins (FLOTs) are principal proteins related to lipid rafts and have been suggested to be involved in APP processing. Here, we report that FLOT-1 binds to BACE1 (beta-site APP cleaving enzyme 1) and that overexpression of CAV-1 or FLOT-1 results in recruiting BACE1 into lipid rafts and influence on beta-secretase activity in cultured cells. Our results show that both CAV-1 and FLOT-1 may modulate beta-secretase activity by interacting with BACE1.