GUCA1B

Guanylyl cyclase-activating protein 2 is an enzyme that in humans is encoded by the GUCA1B gene. Alternative names:
 * Guanylate cyclase activator 1B
 * Retinal guanylyl cyclase activator protein p24

Biological Role
Guanylyl cyclase-activating protein 2 is proposed to play a role in dark adaptation. Under scotopic conditions, calcium ions bind to three putative EF-hand calcium binding motifs which reduces the protein's ability to stimulate guanylyl cyclase. This contributes to the maintained responsiveness of rod photoreceptors through hyperpolarizing them during sustained darkness.