Fig. 5. Selective SNARE and Munc18 isoforms knockdown (K.D.). (A) Endogenous VAMP2, VAMP3, Stx3, Stx4, SNAP23, Munc18b and Munc18c were selectively knocked down using specific siRNAs. Cells were transfected with siRNA specifically targeting each protein (indicated on top of each lane) or with control siRNA (Mock), lysed and analyzed at 48 hours after transfection. 15 µg of each cell lysate were probed with all antibodies against SNARE and Munc18 isoforms (indicated on the left) to confirm the specificity of the knockdown. Protein expression levels were decreased by at least 75%. Actin was used as a loading control.