GUCA1B
Description
The GUCA1B (guanylate cyclase activator 1B) is a protein-coding gene located on chromosome 6.
GUCA1B encodes guanylyl cyclase-activating protein 2, an enzyme that plays a role in dark adaptation. In low light conditions, calcium ions bind to the protein, reducing its ability to stimulate guanylyl cyclase. This maintains the responsiveness of rod photoreceptors by hyperpolarizing them during prolonged darkness.
GUCA1B stimulates the activity of two retinal guanylyl cyclases, GUCY2D and GUCY2F, when the concentration of free calcium ions is low. However, when the concentration of free calcium ions is high, it inhibits their activity. This calcium-dependent regulation of guanylyl cyclases is essential for the recovery of rod photoreceptors to their dark state after exposure to light. GUCA1B may also play a role in the response and recovery of cone photoreceptors in bright light.
GUCA1B is also known as GCAP 2, GCAP-2, GCAP-II, GCAP2, GUCA2, RP48.
