Figure 1.

ELISA experiments measuring the protein tyrosine kinase activity as a function of time after the mixing of two appropriately transfected DAMI cell populations. β-APP-transfected cells with PS-1-transfected cells (A); β-APP-transfected cells with PS-2-transfected cells (B); pcDNA3- (vector only) transfected cells with PS-1-transfected cells (C); PS-1-transfected cells (D), or PS-2-transfected cells (E), first treated with specific anti-PS-1 or anti-PS-2 antibodies, respectively, before mixing with β-APP-transfected cells.