Cyclic nucleotide phosphodiesterase 6 (PDE6)

Cyclic nucleotide phosphodiesterase 6 (PDE6) is a key enzyme found primarily in the photoreceptor cells of the retina (rods and cones) and is responsible for hydrolyzing cGMP, a critical second messenger in the phototransduction cascade[2][5]. The enzyme consists of catalytic subunits (PDE6A in rod cells, PDE6B in rods, PDE6C in cones) and inhibitory γ subunits (PDE6G in rods, PDE6H in cones)[2][5]. PDE6 activity is essential for the conversion of light signals into electrical signals in the retina, enabling vision[2][5][7]. Dysfunction or genetic mutations in PDE6 are linked to retinal degenerative diseases, such as retinitis pigmentosa and congenital stationary night blindness[2][5]. While there are no clinically used, selective PDE6 drugs, off-target effects from PDE5 inhibitors like sildenafil provide evidence of its role in visual function and potential safety considerations[2][7].

Other names

Photoreceptor phosphodiesterasecGMP-phosphodiesterase 6Rod/cone phosphodiesterasePDE6A (rod α subunit), PDE6B (rod β subunit), PDE6C (cone α′ subunit), PDE6G (γ subunit, rods), PDE6H (γ′ subunit, cones)

Phosphodiesterase inhibitors (e.g., sildenafil): increase cGMP by inhibiting hydrolysis; when acting on PDE6, this can affect visual signal transduction and cause transient visual disturbances[2][7].