FIGURE 1.

Aβ induces β₂AR degradation in vivo and in vitro. A, the endogenous β₂AR in cerebral tissues from wild type (WT) and presenilin 1/amyloid precursor protein (PS1/APP) double transgenic mice were examined with Western blot and quantified. n = 6; **, p < 0.01, versus control by unpaired t test. IP, immunoprecipitate. B, HEK293 cells expressing FLAG-tagged human β₂AR were stimulated with either Aβ (10⁻⁶ m) or isoproterenol (Iso, 10⁻⁷ m) for 4 h. The remaining biotin-labeled β₂ARs were isolated and blotted, and the Western blots (WB) were quantified. n = 6; **, p < 0.01 versus control by one-way ANOVA. C, HEK293 cells expressing FLAG-β₂AR were stimulated with Aβ (10⁻⁶ m) or isoproterenol (10⁻⁷ m) for 40 min, and cells were costained with anti-FLAG and anti-Lamp I antibodies.