In mammals, SAP25 is involved in the transcriptional repression mediated by the mSIN3 complex, which consists of at least SAP30, SAP45/Sds3, SAP130, SAP180/BCAA, RBP1, HDAC1 (histone deacetylase1), HDAC2, RbAp46, and RbAp48 []. The mSIN3 complex can be recruited by sequence-specific DNA binding transcription factors and chromatin-binding proteins to specific regions of the genome and regulate their transcription []. SAP25 binds to the the PAH1 domain of mSin3A and changes the conformation of the complex that affects its protein-protein interaction []. SAP25 can be actively exported from the nucleus to cytoplasm by a CRM1-dependent nuclear export pathway. Its localisation is regulated by promyelocytic leukemia protein (PML), which induces a nuclear accumulation of SAP25 [].
