Figure 3

Dictyostelium have PS-dependent γ-secretase activity that processes human APP to release Aβ peptides. (A) Schematic showing various APP derived products and their respective sizes. (B) ΔN-APP, a truncated human APP expressed in transformed wild type (WT) and ps1-null cells were analyzed for secreted levels of Aβ40 and Aβ42 peptides by quantitative ELISA. Fresh media and media conditioned by native WT cells were used a negative controls. Bars indicate standard errors derived from two independent experiments, each with two replicates. (C) Protein samples were collected from native and APP-expressing CHO cells untreated or treated with DAPT, from growing WT Dictyostelium or WT, aph1-null and ps1/2-null Dictyostelium that express ΔN-APP. APP expression and processing was determined by immunoblot assay using anti-APP C-terminus antibodies. Permissions: McMains, V.C. et al. (2010). Dictyostelium possesses highly diverged presenilin/γ-secretase that regulates growth and cell-fate specification and can accurately process human APP: a system for functional studies of the presenilin/γ-secretase complex. Dis. Model. Mech. 3, pp. 581-594.