Regulation of phosphorylation of Ser655 of APP in PC12 cells
PC12 cells were treated with phorbol ester (PDBu), okadaic acid (Oka), a combination of PDBu and okadaic acid (PDBu/Oka), or without any addition (—) for 1 hr. APP was recovered by immunoprecipitation with G-369 antibody, and samples were subjected to SDS-PAGE and immunoblotting as described. (a) Membrane strips were probed with either the pAbS655 (left) or G-369 (right) antibodies. The arrows indicate the positions of mature and immature APP isoforms. (b) The levels of phosphorylation of Ser655 in mAPP770/751 (left) and the total amount of mAPP770/751 (right) were determined by using a Molecular Dynamics PhosphorImager. In each case, the results were normalized to the values obtained without any addition. The data shown are the averages of two independent studies.