Increase of γ-secretase activity in brains of <i>PS1</i> mice.

<p>(A) Protein extracts (20 µg each) from brains of <i>PS1</i> transgenic (lanes 1–3) and non-transgenic mice (lanes 4–6) were immunoblotted with anti-sera specific to Nct, PS1-CTF, PEN2, PS2-CTF, or Actin. (B) Quantification of signals of Nct, Pen-2, and PS2-CTF in protein blots by Image J program. The signal density was normalized using Actin signals derived from the same blot. (C) In vitro γ-secretase assay of brain extracts of wild type, <i>PS1</i> transgenic, and <i>Nct^+/−</i> mice. The data were average from 4 samples. (D) The CHAPSO solubilized membrane proteins from wild type and <i>PS1</i> transgenic mice were incubated with Compound 4 followed by precipitation with streptavidin-coupled beads. Solubilized membranes before ligand addition (Input: 10% of total), captured fraction (Capture<i>:</i> 20% of total) of the affinity ligand and the corresponding supernatants after capture (Unbound: 7.5% of total) were analyzed by Western blot using antisera specific to Nct, PS1-CTF, PS1-NTF, or BACE1. (E) Quantification of signals of Nct levels from in protein blots by Image J program. The signal density was normalized using BACE1 signals derived from the same blot.