Figure 1.

GB1–GB1 interaction in heterologous system. (A) GB1–GB1 interaction detected by cell-surface co-immunoprecipitation. Anti-HA (left) and anti-Flag (right) immunoblots performed on anti-Flag immunoprecipitate (top) and the corresponding lysate (bottom) obtained from COS-7 cells transfected with the indicated constructs. Lane 4 corresponds to mock-transfected cells. The gels are representative of three independent experiments. The bands at high molecular weight (over 250 kDa) represent the multimeric forms of the receptors. (B) GB1 cell-surface expression assessed by binding of the GB1 selective non-permeant antagonist [³H]-CGP54626A either on COS-7 cells expressing GB1 and GB2 or on mouse cortical neurons (E15.5)—15 DIV expressed as pmol of bound ligand per mg of total amount of proteins. No [³H]-CGP54626A binding could be detected on non-transfected COS-7 cells. Data are mean±s.e.m. of three individual experiments each performed in triplicate. P>0.05 in a paired t-test. (C) FRET intensity measured on COS-7 cells between the indicated Snap-tag-labelled subunits. Data are mean±s.e.m. of four individual experiments each performed in triplicate.