FIG. 3.

Soluble APP antagonized TGFβ2-induced death. (A to C) F11 cells (7 × 10⁴ cells/well in 6-well plates) were transfected with 0.25 μg of the pcDNA3 vector (A), pcDNA3-wtAPP (B), or pcDNA3-TGFβRII (C). At 36 h after transfection, cells were combined with the indicated concentrations of TGFβ1 or TGFβ2 in the presence of the indicated amounts of sAPP or BSA as a competitor. Immunofluorescence-based binding assays were performed as described in Materials and Methods. (D) F11 cells (7 × 10⁴ cells/well in 6-well plates) were transfected with 0.25 μg of pcDNA3-wtAPP (upper panel) or pcDNA3-TGFβRII (lower panel). At 36 h after transfection, cells were combined with 1 nM TGFβ2 in the presence of 10 nM sAPP or BSA. Cell lysates (10 μg in each lane) were immunoblotted with antibody to APP (22C11) (upper) or TGFβRII (lower) as well as actin (upper and lower).