Retinal rod rhodopsin-sensitive cGMP 3',5'-cyclic phosphodiesterase (PDE6) (PDE6)

Phosphodiesterase 6 (PDE6) is a central effector enzyme in the vertebrate visual phototransduction pathway, primarily located in the outer segments of retinal rod and cone photoreceptor cells (UniProt P16499). Upon activation by the G-protein transducin in response to light, PDE6 rapidly hydrolyzes cyclic guanosine monophosphate (cGMP), leading to the closure of cGMP-gated cation channels and subsequent hyperpolarization of the photoreceptor membrane (PubMed: 25635045). This process effectively converts light stimuli into electrical signals that are processed by the brain. The enzyme exists as a heterotetramer, and its activity is tightly regulated by inhibitory gamma subunits. Mutations in the genes encoding these subunits, such as PDE6A and PDE6B, are associated with hereditary retinal degenerations like retinitis pigmentosa (PubMed: 23555248). While not a primary therapeutic target for activation, PDE6 is frequently involved in off-target drug interactions. For instance, PDE5 inhibitors like sildenafil can cross-react with PDE6, leading to transient visual side effects such as blue-tinted vision or cyanopsia (StatPearls: NBK526057). Understanding PDE6 kinetics is crucial for developing treatments for vision loss and managing the side effect profiles of systemic phosphodiesterase inhibitors.

Other names

Phosphodiesterase 6cGMP-specific 3',5'-cyclic phosphodiesteraseRod cGMP-specific 3',5'-cyclic phosphodiesteraseCone cGMP-specific 3',5'-cyclic phosphodiesterasePDE6APDE6BPDE6CPDE6GPDE6HActivated PDE6PDE6*

Inhibition of cGMP hydrolysis in photoreceptor cells