Fig. 6

The “protective” APP A673T mutation decreases cleavage by meprin β. a, b 15 nM recombinant meprin β was incubated with synthetic APP peptides at 37 °C. HPLC analysis showed that processing kinetics of APP A673T were decreased (b) compared to wt APP (a) (see also Additional file 4). c Supernatants of HEK-293 T cells, transiently transfected with APPwt or APP A673T mutant and co-transfected with meprin β or empty vector were immunoprecipitated with anti-Aβ 6E10-Dynabeads, subsequently separated on an 8 M urea gel and probed with 6E10. The Aβ2-40 band, visible in samples transfected with APPwt and meprin β, is slightly shifted in samples transfected with APP A673T and meprin β. All samples were run on one gel but rearranged for better presentation. d A significant decrease of the Aβ2-40/1-40 ratio was observed in culture supernatants of cells co-transfected with APP A673T and meprin β compared to cells co-transfected with APPwt and meprin β (graph shows mean ± SEM (n = 5); statistical significance: *, p = 0.0317; t-test)