APP-BP1 expression decreases PS1-CTF stability in primary neurons. Primary neurons were infected with mycAPP-BP1 or p1005+ vector virus for 14 hrs before harvesting. Levels of the rat endogenous PS1 and PS1-CTF were examined by western blots. A representative PS1-CTF blot was shown in A. The same blot was reprobed with the rabbit anti-nicastrin or mouse anti-γ-tubulin antibodies after stripping. B, Quantitative western blot analyses show significant reduction of PS1-CTF in APP-BP1 expressing neurons (n = 3, p < 0.049, one tail t-Test).