The binding of PGC-1α to PPARγ is through the
PGC-1α ID1 LXXLL motif. A, the overall
structure of the PPARγ·rosiglitazone·PGC-1α complex
in ribbon representation. PPARγ is red, the PGC-1α is in
yellow, and the bound rosiglitazone is shown in stick representation
with carbon and oxygen atoms depicted in green and red,
respectively. B, a 2Fo - Fc
electron density map (1.0 σ) showing the binding interface of
PPARγ and PGC-1α. C, an alignment of core sequences of
PGC-1α ID1 and ID2. D and E, the roles of PGC-1α
ID1 and ID2 in the interaction with PPARγ and ERRα. Mammalian
two-hybrid assays were performed in COS-7 cells. The PGC-1α fragment
that contains both ID1 and ID2 was fused to the Gal4 DNA-binding domain, and
the LBDs of ERRα and PPARγ were fused with VP16 AD. The
ligand-dependent interaction of PPARγ with PGC-1α was analyzed
using 1 μm rosiglitazone (Rosi).