Fig. 6. Ectopic expression of syntaxin 1 did not affect transferrin recycling. HeLa cells were transfected with syntaxin 1 (upper panels) or co-transfected with syntaxin 1 and nSec1 (lower panels). 24 hours later cells were allowed to internalize transferrin for 1 hour at 37°C, washed and either fixed immediately (uptake) or incubated for a further 1 hour at 37°C before fixation (release). Notice that both the uptake and the release of transferrin were comparable in both kinds of transfected cells and indistinguishable from non-transfected cells, independently of the intracellular distribution of syntaxin 1. Bar, 5 µm.