Immunoblotting

All protein samples were reduced in × 1 lithium dodecyl sulfate (LDS) sample buffer (Invitrogen) supplemented with 1% β-mercaptoethanol for 10 min at 70 °C. Proteins were separated on NuPAGE Novex 4–12% Bis-Tris polyacrylamide gels (Invitrogen) in MOPS buffer and then transferred to nitrocellulose membrane using the Trans-Blot Turbo transfer system (BioRad). For immunoblotting, membranes were blocked in Tris-buffered saline+0.05% Tween-20 (TBST) with 5% milk powder for 1 hour at room temperature before incubation with primary antibodies diluted in blocking buffer. The following primary antibodies were used in this study: DAKO against total Tau (DAKO, A0024, 1:1,000), anti-Synaptobrevin 2 (Synaptic Systems Clone 69.1, 1:1,000), anti-Synaptotagmin (DSHB, Asv48, 1:1,000), anti-Synapsin (Merck Millipore AB1543P, 1:1,000), anti-Synaptophysin (Synaptic Systems Clone 7.2, 1:1,000) and anti-Tubulin (DSHB, E7, 1:5000). After incubation with primary antibodies, HRP-conjugated species-specific secondary antibodies were added at a concentration of 1:10,000 for 1 hour at room temperature. Signal was detected using the Western Lightning Plus ECL kit (Perkin Elmer) and imaged on a Fuji-Film digital imaging system. Uncropped immunoblot images for all blots in this study can be found in Supplementary Fig. 17.