UC San Diego

Cyclic adenosine monophosphate (cAMP) is a second messenger that is derived from adenosine triphosphate (ATP) and is used for many biological signal transduction processes. cAMP is one of the best known intracellular second messengers after calcium (Ca2+). In many organisms, including humans, various types of ligands bind to G-protein-linked cell surface receptors and activate G proteins. Trimeric G proteins are disassembled by hydrolysis of GTP and can activate transmembrane adenylyl cyclases that convert ATP to cAMP. Phosphodiesterases then hydrolyse cAMP into AMP by breaking the phosphodiester bond. As the concentration of cAMP increases, it relays signals by binding to the regulatory subunits of PKA (cAMP-dependant protein kinase), to one of the members of the Epac family, or to cyclic nucleotide-gated (CNG) channels. Tools are available to manipulate or monitor cAMP in live cells, but they suffer a number of limitations that make them hard to use for imaging experiments. Here, I modify some of these tools to improve them for use in these experiments.