ChIP mass spectrometry analysis identifies TRPS1 as a PR interacting protein. (A) Venn diagram shows the distribution and overlap of the identified proteins complexing with PR in the VC, R5020, TPA, and R5020+TPA treatment groups (IgG-bound proteins are excluded), n = 3 independent replicates. (B) Venn diagram shows unique and common proteins identified in R5020 or R5020+TPA treatment groups, and the list of the proteins is provided. (C) T47D cells were treated with VC, 10 nM R5020, 1 μM TPA, or R5020+TPA for 24 hours. Nuclear and cytoplasmic extracts were isolated and immunoblotted for TRPS1, PR, and actin. (D) T47D cells were treated with VC, 10 nM R5020, 1 μM TPA, or R5020+TPA for 24 hours. Nuclear extracts were prepared and immunoprecipitated with PR and immunoblotted for TRPS1 and PR. (E) MCF7 cells were pretreated with E2 (1 nM) for 24 hours and treated with VC, 10 nM R5020, 1 μM TPA, or R5020+TPA for 24 hours. Nuclear and cytoplasmic extracts were isolated and immunoblotted for TRPS1, PR, and actin. (F) MCF7 cells were pretreated with E2 (1 nM) for 24 hours and treated with VC, 10 nM R5020, 1 μM TPA, or R5020+TPA for 24 hours. Nuclear extracts were prepared and immunoprecipitated with PR and immunoblotted for TRPS1 and PR. IB, immunoblot; IP, immunoprecipitation.