Cyclic 3’5’ adenosine monophosphate (cAMP) is a key second messenger that is responsible for regulating many pivotal signaling processes in all mammalian cell types (Tasken and Aandahl 2004). It influences cell growth, differentiation, shape, and movement as well as processes such a cardiac contraction, metabolism, water retention, learning, and memory. Most intriguingly, however, cAMP can selectively regulate a variety of very different processes in any one particular cell type. Indeed, uncovering the molecular mechanisms that allow cAMP to selectively regulate disparate processes within a single cell has provided a major challenge. Only very recently has the means whereby cAMP signaling is compartmentalized in cells begun to be understood (Tasken and Aandahl 2004; Baillie et al. 2005; Willoughby and Cooper 2007). One key requirement is for spatially discrete signaling complexes to be assembled...