Anti syntaxin 1b

For reverse co-IPs, protein G-Sepharose 4 Fast Flow beads (GE Healthcare) were pre-bound with 4 μg of the following antibodies, respectively: anti-mitochondrial creatine kinase U-type (MtCK, Abcam, San Francisco, catalog no. ab76506); anti-β-synuclein (Abcam, catalog no. ab76111); anti-apoE (Abcam, catalog no. ab1906); anti-apoAI (Santa Cruz Biotechnology, Dallas, TX, catalog no. sc-30089); anti-syntaxin 1B (Synaptic Systems, Göttingen, Germany, catalog no. 110402); anti-synapsin 1 (Abcam, catalog no. ab8); anti-synaptogyrin-3 (Santa Cruz Biotechnology, catalog no. sc-68936); anti-synaptophysin (Santa Cruz Biotechnology, catalog no. sc-9116); and anti-synaptotagmin (Millipore, catalog no. MAB5200). These samples were then incubated with 1 mg of lysate at 4 °C overnight. To verify the binding preference of Tau isoforms, dephosphorylated lysates were used adapting a dephosphorylation protocol obtained from New England Biolabs. Beads were washed extensively with IP washing buffer and eluted in 2× SDS-PAGE sample buffer for subsequent Western blot analysis. Blots were probed with the following antibodies: anti-creatine kinase U-type; mitochondrial (MtCK); anti-β-synuclein; anti-apoE; anti-apoAI; anti-syntaxin 1B; anti-synapsin 1; anti-synaptogyrin-3; anti-synaptophysin; anti-synaptotagmin, and anti-Tau. For quantification, ImageJ was used.