Figure 2.
Comparative ligand binding and signal transducing activities of OB-RL(wt) and OB-RL(fa). GT1–7 cells were cotransfected with the reporter gene construct HRRE-SEAP (1 μg/ml) and the indicated amounts of cDNAs encoding either murine OB-RL(wt) or OB-RL(fa). 24 h after transfection, cultures were sub-divided and analyzed for (A) AP-OB binding activity or (B) treated with mouse leptin (100 ng/ml) for 24 h and assayed for reporter gene induction as described in Fig. 1 (columns represent the averages of two measurements and the bars reflect differences between the two). (C) Hypothetical constitutive and ligand induced signaling activity for OB-RL(fa) when normalized to OB-RL(wt) cell surface binding activity (as measured in A).