Guanylate cyclase activator 1B (GUCA1B)

Guanylate cyclase activator 1B (GUCA1B), commonly called guanylyl cyclase-activating protein 2 (GCAP2), is a calcium-binding protein predominantly expressed in retinal photoreceptors. It plays a central role in the recovery phase of visual phototransduction by regulating membrane-bound photoreceptor guanylate cyclases (GCs, particularly GUCY2D and GUCY2F) in a calcium-sensitive manner. When intracellular calcium is low (following photoreceptor stimulation by light), GUCA1B stimulates GCs to produce cyclic GMP, facilitating the return to the dark state. Elevations in calcium inhibit this activity, tightly coupling GUCA1B’s function to photoreceptor signaling and dark adaptation. Mutations in GUCA1B are associated with autosomal dominant forms of retinitis pigmentosa and can cause retinal degeneration due to disrupted regulation of cyclic GMP metabolism and photoreceptor recovery[1][3][5][4][8][9][11].

Other names

Guanylyl cyclase-activating protein 2GCAP2Guanylate cyclase activator 1B (retina)GCAP 2GCAP-2GCAP-IIGUCA2RP48guanylyl cyclase-activating protein 2retinal guanylyl cyclase activator protein p24