Fig. S7.
Quantification of the fluorescence signal of membrane-bound hGBP1 and calculation of the contact length in the tethering assay. Typical images of GUVs for AF-hGBP1F in the presence of GTPγS for the protein channel of fluorescence (A), the lipid channel of fluorescence (B), or the merge of two fluorescence channels (C) as an example for quantification of the fluorescence signal of membrane-bound hGBP1. (Scale bar, 5 μm.) (D) Superimposed fluorescence intensity profiles across narrow equatorial rectangle as shown in B, taken from A and B. (E) Schematic representation of the image-processing algorithm for contact length calculation in tethering assay. The fluorescent signal from the lipid channel of fluorescence was set to the value of 1 when fluorescent intensity was higher than the threshold value and set to the value of 0 otherwise. The contact length (L) between the two vesicles is indicated. Points of membrane differentiation are indicated as red stars. The gray outlined arrow indicates that the two rectangles correspond to each other.