Dr. Levin has been studying the cAMP signaling pathway for over 25 years and adenylyl cyclases for over 20. As a Graduate Student in the Laboratory of Dr. Mark J. Zoller at Cold Spring Harbor Laboratory, he used molecular genetics and biochemistry to study the regulation of Protein Kinase A, the predominant cAMP effector protein in cells. As a Post-doctoral Fellow in the laboratory of Dr. Randall R. Reed at Johns Hopkins School of Medicine, he cloned and characterized the first Drosophila adenylyl cyclase, the Rutabaga adenylyl cyclase, shown to be important for learning and memory. As a member of the Pharmacology Department of Weill Cornell Medical College, he collaborated with Dr. Buck to identify, clone, and biochemically characterize a novel form of adenylyl cyclase in mammals, the soluble adenylyl cyclase (sAC). He and Dr. Buck demonstrated that sAC is uniquely regulated by bicarbonate anions and that it is distributed throughout the cell providing a local source of cAMP for intracellular cAMP signaling microdomains. Drs. Levin and Buck remain collaborators studying the biochemistry and biology of mammalian sAC and evolutionarily related adenylyl cyclases. They have combined their laboratories into a combined research program studying bicarbonate/carbon dioxide/pH chemosensing via the second messenger cAMP.