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Updated: Sep 27, 2026

Interactions with and Membrane Permeabilization of Brain Mitochondria by Amyloid Fibrils
Published on: September 28, 2019
The receptor-bound N-terminal ectodomain of the amyloid precursor protein is associated with membrane rafts
Ritva Tikkanen1, Ann Icking, Peter Beicht
1Institute of Cell Biology and Bonner Forum Biomedizin University of Bonn, Ulrich-Haberland Strasse 61a, D-53121 Bonn, Germany
Abstract:
The soluble N-terminal ectodomain of amyloid precursor protein (sAPP), resulting from alpha-secretase-mediated proteolytic processing, has been shown to function as a growth factor for epithelial cells, including keratinocytes and thyrocytes. Extracellularly applied sAPP binds to a cell surface receptor and exhibits a patchy binding pattern reminiscent of that observed for raft proteins. Here we show that (i) the receptor-bound sAPP resides in a detergent-insoluble membrane microdomain which cofractionates in density gradients with cholesterol-rich membrane rafts and caveolae; (ii) the sAPP-binding microdomains are different from caveolae; and (iii) sAPP is capable of binding to isolated rafts and inducing tyrosine phosphorylation of some raft proteins. These observations suggest that a novel type of membrane raft is involved in sAPP signaling.
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