Postmortem changes in the phosphorylation state of tau-protein in the rat brain.
The phosphorylation state of tau-protein is crucial for the regulation of neuronal microtubule organization. Functional conclusions on tau-protein require an accurate assessment of phosphorylated sites. Therefore, the in vivo distribution and postmortem preservation of some phospho-epitopes on tau-protein were examined in the rat brain under different fixation and preparation conditions. Detection of tau-protein with a phosphorylation-independent antiserum revealed both axonal and somatodendritic localizations, which were not influenced by a postmortem interval of 30 min. The phospho-epitopes recognized by 12E8, AT8, and PHF-1 were mainly localized in the somatodendritic compartment. The binding sites of AT8 and PHF-1 were rapidly dephosphorylated postmortem, whereas the Tau-1 epitope was unmasked in the somatodendritic region. The axonally located phospho-epitope of AT270 and the nuclear epitope of AT100 were still detectable after a postmortem interval of 30 min. Postmortem dephosphorylation and inhibition of this process by PP1 and/or PP2A was further demonstrated on Western blot. In conclusion, rapid processing of tau-protein is essential for the correct assessment of investigations on phospho-isoforms.
Gärtner
U
U
Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, University of Leipzig, Germany.
Janke
C
C
Holzer
M
M
Vanmechelen
E
E
Arendt
T
T
D000818:Animals; D000906:Antibodies; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D015180:Electrophoresis, Gel, Two-Dimensional; D000939:Epitopes; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D019579:Neocortex / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D011180:Postmortem Changes; D020033:Protein Isoforms; D051381:Rats; D017208:Rats, Wistar; D016707:Tissue Fixation; D016875:tau Proteins / Q000276:immunology / Q000378:metabolism*
D000906:Antibodies; D000939:Epitopes; D020033:Protein Isoforms; D016875:tau Proteins