PMID: 22654059 , Related PDB id: 2LP1

Authors:

Barrett PJ, Song Y, Van Horn WD, Hustedt EJ, Schafer JM, Hadziselimovic A, Beel AJ, Sanders CR

Title:

The amyloid precursor protein has a flexible transmembrane domain and binds cholesterol.

Journal:

Science. 2012 Jun 1;336(6085):1168-71.

Abstract:

C99 is the transmembrane carboxyl-terminal domain of the amyloid precursor protein that is cleaved by gamma-secretase to release the amyloid-beta polypeptides, which are associated with Alzheimer's disease. Nuclear magnetic resonance and electron paramagnetic resonance spectroscopy show that the extracellular amino terminus of C99 includes a surface-embedded "N-helix" followed by a short "N-loop" connecting to the transmembrane domain (TMD). The TMD is a flexibly curved alpha helix, making it well suited for processive cleavage by gamma-secretase. Titration of C99 reveals a binding site for cholesterol, providing mechanistic insight into how cholesterol promotes amyloidogenesis. Membrane-buried GXXXG motifs (G, Gly; X, any amino acid), which have an established role in oligomerization, were also shown to play a key role in cholesterol binding. The structure and cholesterol binding properties of C99 may aid in the design of Alzheimer's therapeutics.