Intracellular signal transduction is mediated by a network of molecules that are often ubiquitous and widely distributed. It is the particular combination of these protein kinases, phosphatases, ion channels and other types of macromolecules that defines the individual signaling pathway and the specific cellular response to each unique extracellular stimulus. An emerging concept in the field of signal transduction is the existence of nodes within this network where multiple signaling pathways converge and share common molecules, thereby facilitating crosstalk between pathways. Molecules that participate in these centers of integration are of special therapeutic interest. The Kapiloff Laboratory is committed to the elucidation of the signal transduction pathways of the cardiac myocyte and retinal ganglion cells. In particular, we are interested in the role that scaffold proteins play is the regulation of signaling. A major focus of our laboratory has been the characterization of the mAKAP complex found on the nuclear membrane. mAKAP is an example of an A-kinase anchoring protein (AKAP). AKAPs are scaffold proteins that target the cAMP-dependent protein kinase PKA to discrete physical locations within the cell. By binding multiple signaling molecules, AKAPs often serve as nodes in the cellular signaling network, facilitating crosstalk between pathways that involve cAMP and other intracellular second messengers. We have recently demonstrated that the mAKAP complex is involved in the transduction of pro-hypertrophic signaling in the myocyte.