Abnormalities of Phosphatase 2A (PP2A) for Diagnosis and Treatment of Alzheimer's Disease

A method of diagnosing Alzheimer's disease in a subject, said method comprising the steps of:

• a. obtaining a cell sample from said subject;
• b. contacting said cell sample with an agent that stimulates phosphorylation of a PP2A substrate to stimulate the cells;
• and
• c. comparing the level of PP2A gene expression in said stimulated cells to the level of PP2A gene expression in unstimulated cells of the same type from said subject, wherein a lack of increased PP2A gene expression in stimulated cells as compared to unstimulated cells indicates the presence of Alzheimer's disease.

A method of diagnosing Alzheimer's disease in a subject, said method comprising the steps of:

• a. obtaining a cell sample from a subject;
• b. contacting said cell sample and control cells with a first agent that stimulates phosphorylation of a substrate of PP2A and, a second agent that is an inhibitor of PP2A;
• c. measuring the level of phosphorylation of the PP2A substrate at a predetermined time after initiating the contacting step;
• and
• d. comparing the level of phosphorylation of the PP2A substrate in said cell sample to the level of PP2A substrate phosphorylation in control cells at the same predetermined time, wherein a lack of additional effect of the PP2A inhibitor on the extent of the PP2A substrate phosphorylation in the cell sample compared to control cells indicates the presence of Alzheimer's disease.

A method of diagnosing Alzheimer's disease in a subject, said method comprising the steps of:

• a. obtaining a cell sample from a subject;
• b. contacting control cells and said cell sample with a first agent that stimulates phosphorylation of a substrate of PP2A, wherein said contacting is done in the presence and the absence of a second agent that is an inhibitor of PP2A;
• c. measuring the level of phosphorylation of the PP2A substrate from said control cells and said cell sample at a predetermined time after initiating the contacting step (b);
• and
• d. comparing the level of phosphorylation of the P2A substrate from said cell sample in the presence and the absence of said second agent that is an inhibitor of PP2A, wherein a lack of a significant difference between the extent of PP2A substrate phosphorylation in the presence and the absence of said second agent indicates the presence of Alzheimer's disease.

A method of diagnosing Alzheimer's disease in a subject, said method comprising the steps of:

• a. obtaining a cell sample from said subject;
• and
• b. contacting said sample with an agent that stimulates phosphorylation of Erk1/2;
• and
• c. detecting the subcellular distribution of phosphorylated Erk1/2, wherein an extranuclear distribution of phosphorylated Erk1/2 indicates the presence of Alzheimer's disease.