FIGURE 4.

Binding of different CPXs deletion/mutant constructs to SNARE complexes. HeLa t-cells were co-transfected with the desired CPX-I deletion/mutant construct and with a plasmid encoding for flipped VAMP2 in order to form cis-SNARE complexes on the cell surface. Afterward, CPX-I-GPI was cleaved off from its GPI anchor motif using PI-PLC for 30 min at 37 °C, and the remaining CPX-I bound on the cell surface was determined by immunofluorescence using anti-AU1 antibody (22). The dashed red line corresponds to the basal fluorescent intensity background quantified when neither SNAREs nor CPXs are present (negative control). The dashed green line corresponds to the mean fluorescent intensity of constructs that bind SNARE complexes.