Rod-specific cGMP phosphodiesterase 6B (PDE6B)

Rod-specific cGMP phosphodiesterase 6B (PDE6B) is a key enzyme in the visual phototransduction pathway, located in the outer segments of rod photoreceptor cells [4, 12]. It functions as the beta subunit of the heterotrimeric PDE6 complex, which is responsible for regulating the levels of the second messenger cyclic guanosine monophosphate (cGMP) in response to light [7, 8]. When light activates rhodopsin and transducin, PDE6B catalyzes the hydrolysis of cGMP, causing cGMP-gated cation channels to close and the cell to hyperpolarize, thereby transmitting a visual signal to the brain [7, 12]. Mutations in the PDE6B gene lead to the accumulation of toxic levels of cGMP, resulting in the progressive death of rod cells and subsequent loss of cone cells, which manifests as retinitis pigmentosa or congenital stationary night blindness [3, 10, 15]. Current therapeutic development focuses on gene replacement therapies, such as HORA-PDE6b, which aim to restore functional enzyme activity via subretinal delivery of the wild-type gene [1, 5]. Additionally, PDE6B is an off-target for several non-selective phosphodiesterase inhibitors, which can cause transient visual side effects [10].

Other names

PDEBRP40CSNB3CSNBAD2GMP-PDE betaRod cGMP-phosphodiesterase beta-subunitPhosphodiesterase 6B, cGMP-specific, rod, beta

Gene replacement therapy to restore functional PDE6B protein expression; competitive inhibition of cGMP hydrolysis by small molecule inhibitors.