Phosphodiesterase 4A (PDE4A); Phosphodiesterase 4D (PDE4D) (PDE4A; PDE4D)

Phosphodiesterase 4A and Phosphodiesterase 4D are cAMP-specific hydrolase enzymes encoded by separate genes within the PDE4 family. Both are functional dimers with conserved catalytic domains and variable N-terminal regions that generate numerous isoforms via alternative splicing, conferring specific localization and regulation. They are most abundantly expressed in the brain and immune cells, where they regulate cAMP breakdown and thus influence memory, neuroplasticity, inflammatory response, and cell proliferation. Dysregulation of PDE4A and PDE4D has been implicated in cognitive disorders, cancer, and psychiatric diseases, making them important drug targets for small molecule inhibitors such as roflumilast and rolipram. Distinct splice variants play specific biological roles and may display differential sensitivity to kinase regulation or oncogenicity, as evidenced by the stronger cancer-promoting activity of some truncated forms of PDE4D.

Other names

Phosphodiesterase type 4APDE4A isoformcAMP-specific 3’,5’-cyclic phosphodiesterase 4APhosphodiesterase type 4DPDE4D isoformcAMP-specific 3’,5’-cyclic phosphodiesterase 4D

Inhibition of the PDE4A or PDE4D catalytic domain increases intracellular cAMP, leading to changes in cell signaling, anti-inflammatory effects, enhancement of memory processes, and induction of apoptosis in cancer cells.