Jun Dimerization Protein 2: A Multifunctional Transcription Factor in Mammalian Cells

Jun dimerization protein 2 (JDP2) forms a dimeric complex that can include members of the Jun, Fos, ATF-2, Maf and other families of AP-1 proteins. JDP2 acts as a repressor that binds to the AP-1 site in promoters and is a possible tumor-suppressor. We describe here how the transactivation of the c-Jun gene by p300 and ATF-2 involves recruitment of the histone deacetylase complex (HDAC3), with repression of retinoic acid-induced (RA-induced) transcription of the c- Jun gene and subsequent inhibition of the RA-mediated differentiation of F9 cells. We summarize that JDP2 has activities associated with histone binding and inhibition of histone acetyltransferases (INHAT), as well as with the regulation of chromatin assembly. These observations indicate that JDP2 not only acts as a sequence-specific DNA-binding protein but also controls the transcription of AP-1-responsive genes by direct regulation of histone modification. We discuss here a new perspective on the role of JDP2 in the chromatin-related mechanism that regulates the transcription of genes that are the targets of AP-1 proteins.