Rescue of syntaxin-1 localization upon reintroduction of the wild-type Munc18-1-EmGFP, but not of K46E/E59K Munc18-1-EmGFP, into Munc18-1/-2 double knockdown clones. Confocal images of D7 cells infected with lentiviruses that express either wild-type Munc18-1-EmGFP (left, top) or K46E/E59K Munc18-1-EmGFP (left, bottom) and stained with anti-syntaxin-1 antibodies followed by red-x-conjugated anti-mouse antibodies (middle). Right panels are merged pictures. Bar, 10 μm.