Figure 1.

YFP-Sec24 overexpression does not disrupt constitutive ER export. Tobacco leaf protoplasts were transfected with a constant amount of α-amylase DNA, with an increasing concentration of DNA encoding either Sec12-GFP (A) or YFP-Sec24 (B). The α-amylase activities in the extracellular medium and cellular fraction were measured and the secretion index, which represents the ratio between the intracellular and extracellular activities, was calculated as previously described (Phillipson et al., 2001). Error bars represent se for three independent experiments.