Abstract: cAMP response element-binding(CREB) proteins are a family of mammalian transcription activators that mediate cAMP and calcium-dependent gene expression through the cAMP response element (CRE). CREB4 is a novel member of the human CREB family. Yeast two-hybrid system revealed that karyopherinα2 may associate with CREB4^215-279aa. Subcellular location of CREB4 and CREB4^1-279aa showed that the GFP-CREB4 fusion protein was localized in cytoplasm, whereas the fusion protein of GFP-CREB4^1-279aa was translocated in nucleus. Our experiments further showed that CREB4 and karyopherinα2 were co-located in cytoplasm,but CREB4^1-279aa and karyopherinα2 were co-located in nucleus. These results suggested that first C-terminal was cleaved and then CREB4was carried into nucleus by karyopherinα2 to activate gene transcription.

Key words: yeast two-hybrid, fluorescent co-location, karyopherinα2, CREB4, yeast two-hybrid, fluorescent co-location, karyopherinα2