Functional interaction of PELP1 with ERα and ERβ in endometrial cells. A, Western blot, analyzing the expression of PELP1 in endometrial cancer cell lines. B, PELP1 enhances the E2-mediated reporter gene activation in Ishikawa cells. C and E, PELP1 potentiates ERα-and ERβ-specific ligand PPT- and DPN-mediated ERE reporter gene transcription. D and G, Equal amounts of cell lysates from Ishikawa cells cultured in 10% serum were subjected to immunoprecipitation (IP) with ERα and ERβ antibodies, followed by Western blotting with PELP1 antibody. F, PELP1 potentiates ERβ-mediated reporter gene activation. Ishikawa cells were cotransfected with 3XERE-luc reporter gene, the ERβ expression vector, with or without the PELP1 expression vector; cells were treated with E2 (10−9 m), and ERE-luc reporter activation was measured after 16 h.