The cAMP response element binding protein-2 (CREB-2) can interact with theC/EBP-homologous protein (CHOP)

cAMP response element binding protein-2 (CREB-2) is a basic leucine zipper (bZIP) factor that was originally described as a repressor of CRE-dependent transcription but that can also act as a transcriptional activator. Moreov er, CREB-2 is able to function in association with the viral Tax protein as an activator of the human T-cell leukemia virus type I (HTLV-I) promoter. Here we show that CREB-2 is able to interact with C/EBP-homologous protein (CHOP), a bZIP transcription factor known to inhibit CAAT/enhancer-dependen t transcription. Cotransfection of CHOP with CREB-2 results in decreased ac tivation driven by the cellular CRE motif or the HTLV-1 proximal Tax-respon sive element, confirming that CREB-2 and CHOP can interact with each other in vivo. (C) 2001 Published by Elsevier Science B.V. on behalf of the Feder ation of European Biochemical Societies.