The tau protein: From physiological to pathological process in Alzheimer's disease

Abstract

Background: Tau is a microtubule-assocaited protein (MAP) that stabilizes microtubule polymers in vitro and in situ. In the central nervous system, tau has been localized in both axonal and somatodendritic compartments of neurons. However, tau protein is associated with neurofibrillary tangles (NFT) in vulnerable neurons in Alzheimer’s disease (AD). Abnormal tau is associated with post-traductional process such as hyperphosphorylation and truncation. Both events are associated to the genesis of paired helical filaments (PHF) of NFT. Methods: We used double and triple immunolabelling with a variety ofantibodies raised tauprotein and analyzed by confocal microscopy.Results:We observed that in undifferentiated cells, the immnunoreactivity of antibodies raised against phosphorylated tau AT100 (212214), pT231 (231), and AD2 (396-404) was found in the nucleus. However, the immunoreactivity of pT231, TG3 and AD2 increased during the cell cycle process: prophase to anaphase, and decreases in cytokinesis phase. Reactivity to AT100, TG3 and pT231 antibobodies was found in the perinuclear area of some neuronal cells named pretangle cells. Those results suggest that the expression of tau protein appears to be associated with various activities, depending on the functional state of the cells. Tau protein in the nucleus may participate in cycling cells and DNA Conclusions: Those results suggest that the expression of tau protein appears to be associated with various activities, depending on the functional state of the cells. Tau protein in the nucleus may participate in cycling cells and DNA protection. In AD this alteration of tau protein in the perinuclear area may be the consequence in part of an aberrant interaction of the disease related protein with DNA, therefore affecting the normal DNA expression and giving place to a genetic stress which alters the expression of proteins needed for normal cellular function and regulation. P2-065 APOLIPOPROTEIN E-e4 IN A JAPANESE POPULATIONWITHALZHEIMER’SDISEASEAND DEMENTIAWITH LEWY BODIES Masaru Tateno, Seiju Kobayashi, Tae Woo Park, Kumiko Utsumi, Hitoshi Sohma, Yoichi M. Ito, Yauo Kokai, Toshikazu Saito, Sapporo Medical University, School of Medicine, Sapporo, Japan; Boston University School of Medicine, Boston, Massachusetts, United States; Sunagawa City Medical Center, Sunagawa, Japan; Sapporo Medical University Center for Medical Education, Sapporo, Japan; Hokkaido University Graduate School, Sapporo, Japan. Contact e-mail: seij@pastel. ocn.ne.jp