ABSTRACT
Calmodulin-stimulated phosphodiesterase (PDE) activity was originally identified in bovine and rat brain. Cyclic nucleotides, particularly Cyclic adenosine 3',5'-monophosphate are established regulators of immune cell function. As is common with most PDE families, the PDE1 enzymes have a primary structure consisting of a somewhat conserved C-terminal catalytic domain and an N-terminal regulatory domain. Phosphorylation has been biochemically characterized as a mechanism for the regulation of both PDE1A and PDE1B. The PDE1 family is comprised of three separate genes: PDE1A, PDE1B, and PDE1C. One of the challenging aspects of PDE research is elucidating a role for individual PDEs in vivo. The brain was one of the first tissues in which PDE1 activity was discovered and a great deal of the initial characterization of PDE1 biochemistry was performed in bovine brain. A great deal of work has characterized the biochemical properties and regulation of PDE1 on a molecular level.
