Identification of a Novel Aspartic Protease (Asp 2) as β-Secretase

Autor: Hussain, Ishrut, Powell, David, Howlett, David R., Tew, David G., Meek, Thomas D., Chapman, Conrad, Gloger, Israel S., Murphy, Kay E., Southan, Christopher D., Ryan, Dominic M., Smith, Trudi S., Simmons, David L., Walsh, Frank S., Dingwall, Colin, Christie, Gary
Zdroj: Molecular and Cellular Neurosciences; December 1999, Vol. 14 Issue: 6 p419-427, 9p
Abstrakt: The Alzheimer's disease β-amyloid peptide (Aβ) is produced by excision from the type 1 integral membrane glycoprotein amyloid precursor protein (APP) by the sequential actions of β- and then γ-secretases. Here we report that Asp 2, a novel transmembrane aspartic protease, has the key activities expected of β-secretase. Transient expression of Asp 2 in cells expressing APP causes an increase in the secretion of the N-terminal fragment of APP and an increase in the cell-associated C-terminal β-secretase APP fragment. Mutation of either of the putative catalytic aspartyl residues in Asp 2 abrogates the production of the fragments characteristic of cleavage at the β-secretase site. The enzyme is present in normal and Alzheimer's disease (AD) brain and is also found in cell lines known to produce Aβ. Asp 2 localizes to the Golgi/endoplasmic reticulum in transfected cells and shows clear colocalization with APP in cells stably expressing the 751-amino-acid isoform of APP.
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