Antibodies and dyes used in these experiments were rat monoclonal anti-tubulin antibody YL1/2 and mouse mAb DM1A purchased from Serotec and Sigma-Aldrich, respectively (1:2,000); and polyclonal rabbit HA tag antibody (MoBiTec). Polyclonal rabbit anti tau-antibody K9JA (DakoCytomation), mAb 12E8 against tau (gift from P. Seubert, Elan Pharma), and antibodies against peroxisomes (gift ofW. Just, University of Heidelberg). The clone of mRFP was provided by R. Tsien (University of California, San Diego). All fluorescent (TRITC, FITC, and AMCA) secondary antibodies were purchased from Dianova.