Fig. 3. Temperature dependence and variation of relative amounts of SDS-resistant SNARE complexes from PC12 cell membranes. (A) An anti-SNAP-25-immunoblot was performed on PC12 cell SDS-membrane-extracts that had been exposed to different temperatures (as indicated) for 5 minutes before separation by SDS-PAGE. (B) SNAP-25-immunoreactive bands of membrane extracts from cells lysates kept at –20°C (lanes 1, 2) or +24°C (lanes 3, 4) for 16 hours before protein preparation. (C) Comparison of 100 kDa and 230 kDa SNAP-25-immunoreactive bands from two independent preparations (lanes 1, 2) of PC12 cells.