CYCLIC-AMP SIGNALING AND CELLULAR PROLIFERATION - REGULATION OF CREB AND CREM

In eukaryotes, transcriptional regulation upon stimulation of the aden ylyl cyclase signalling pathway is mediated by a family of cAMP-respon sive nuclear factors. This family consists of a large number of member s which may act as activators or repressors. These factors contain the basic domain/leucine zipper motifs and bind as dimers to cAMP-respons e elements (CRE). The function of CRE-binding proteins (CREB) is modul ated by phosphorylation by the cAMP-dependent protein kinase. The ICER (inducible cAMP early repressor) protein is the only inducible member of this family and is a product of the CREM gene. The induction of th is powerful repressor is likely to be important for tbe transient natu re of cAMP-induced gene expression. CREB proteins have been found to p lay an important role in the physiology of neuroendocrine functions. I n addition, recent results indicate that CREB and CREM could be involv ed in the proliferation of hepatocytes which follows partial hepatecto my. (C) 1997 Federation of European Biochemical Societies.