MAPT and neurodegenerative disease: As pp32 is an endogenous inhibitor of PP2A (Santa-Coloma, 2003), and the reduction of PP2A activity leading to hyperphosphorylation of tau plays an important role in neurodegenerative diseases (Tanimukai et al., 2009), we further detected the phosphorylated level of tau and investigated whether tau phosphorylation contributes to sipp32-ameliorated learning and memory impairment in Aged-CI mice.