Immunofluorescence staining used polyclonal anti-tau (sc5587, Santa Cruz) and monoclonal anti-Hsp90 (sc-13119, Santa Cruz); double staining used anti-phosphorylated tau AT8 (1:500, Innogenetics) and/or anti-Hsp70 (sc-1060) or anti-Hsp90 (sc-7947, 1:200, Santa Cruz). Western blots were probed with anti-tubulin (1;200, MAB-3408, Chemicon), anti-human tau (1:200, sc-5587, Santa Cruz), or Hsp70 (sc-1060) or Hsp 90 (sc-7947).