Fig. 7

Meprin β cleavage is affected by mutations in APP. a, b Western Blots of 8 M urea gels showed a distinct Aβ2-40 band in HEK-293 T cells transiently co-transfected with APP695wt or APPlon and meprin β. Supernatants were immunoprecipitated for Aβ using 6E10 antibody. Note that APPswe or APPswe/lon transfected cells, co-transfected with meprin β, did not show the Aβ2-40 band (graph shows mean ± SEM (n = 4); statistical significance: * < 0.05; t-test). c, d Subsite cooperativity determines the meprin β cleavage site in APP. Previously identified meprin β cleavage sites in peptides derived from HEK-293 T cell lysates [24] were analyzed by a web-based tool [31] to visualize changes in the preference for certain amino acid residue around the scissile bond (black line). Green color indicate high, red color low preference. Aspartate in P1 position is well preferred in APPwt, but disliked in APPswe