| The novel interaction between RanBPM and TR isoforms was addressed by glutathione S transferase ( GST ) pull down assays and co immunoprecipitation in intact mammalian cells , where RanBPM was shown to bind TRs in a ligand independent fashion . ^^^ We also studied the regions implicated in the interaction with deletion mutants : the principal interacting region of RanBPM is comprised within its carboxyl terminal end and the TR DNA binding domain is sufficient to mediate the interaction . ^^^ This revealed that the stimulating effect on TR transactivation by the full length protein is inhibited in a dose dependent fashion by RanBPM 55 . ^^^ This suggests that although the polyglutaminated region of RanBPM is not required for the binding to TRs , it is required for the stimulation of TR transactivation . ^^^ |