Complexity and versatility of the transcriptional response to cAMP

The large number of CRE binding proteins reveals the complexity of the cellular response to cAMP and possibly suggests the requirements of cell-specificity and potential cross-talk mechanisms with the PKC pathway. The CREM gene constitutes a paradigm that represents another level of complexity. Its modularity of function, which is mediated by alternative and cell-specific splicing events, is an example of the versatility that the cell must accomplish in order to permit normal and regulated cell growth in response to several stimuli. The generation of CREB/CREM-deficent animals by homologous recombination will be an important step in the determination of the precise roles played by the different CRE binding proteins in vivo.