A number of hormones and growth factors have been shown to stimulate target cells via
second messenger pathways that in turn regulate the phosphorylation of specific nuclear
factors. The second messenger cyclic AMP, for example, regulates a striking number of
physiologic processes, including intermediary metabolism, cellular proliferation, and
neuronal signaling, by altering basic patterns of gene expression. Our understanding of
cyclic AMP signaling in the nucleus has expanded considerably over the past decade …