Figure 2. Second proposed binding site of GPR40. By visual inspection, a second possible binding site was proposed between transmembrane helices 3, 4, and 5 on the intracellular side.File:4phuBind3.pngFigure 3. Third proposed binding site of GPR40. By visual inspection, a third possible binding site was proposed between transmembrane helices 1, 2, and 7 on the extracellular side.Figure 3. Third proposed binding site of GPR40. By visual inspection, a third possible binding site was proposed between transmembrane helices 1, 2, and 7 on the extracellular side.