Structural Basis for Bilateral Effects of GW9662 in PPARα Activation
(A) Concentration-dependent bilateral effects of GW9662 on PGC1α recruitment by agonists with various potencies. Data are means ± SEM (n = 3–4).
(B) Bilateral effects of GW9662 (100 μM) on ligand-induced PPARα-LBD thermostability. Data are means ± SEM (n = 3–4) and effects are found to be significant at ∗∗∗p < 0.001.
(C) Crystal structures of PPARα-LBD bound with single fibrate and two or three GW9662 molecules. See also Figure S8.
(D) Covalent cross-linking to Cys 276, in Arm II, but not to Cys 275, in Arm X, is essential for bilateral effects of GW9662 on PPARα regulation to inhibit GW7647 effects and activate clofibric acid effects. Data are means ± SEM (n = 3).
(E) Summary of bilateral effects of GW9662 and alignment of 16 ligands to LBD pockets in the order of ligand potencies in the coactivator recruitment assay; ligand-induced thermostability data were attached. Structural analyses demonstrated the location (circles), the possible location (triangles), or the absence (crosses) of those ligands in each LBD. One fenofibric acid (F) molecule is located at Arm I (as F1), whereas another fenofibric acid molecule is located across Arms II and X (as F2), and the same applies for GW9662, ciprofibrate, clofibric acid, and gemfibrozil.