Control of photoreceptor proteins by Ca2+.
A decrease of cytoplasmic Ca(2+)-concentration in vertebrate photoreceptor cells after illumination is necessary for light adaptation. Although the mechanisms of adaptation is not completely understood, several Ca(2+)-dependent cellular processes have been discovered. Some involve calcium-binding proteins like recoverin, guanylyl cyclase-activating protein and calmodulin, and their target proteins rhodopsin kinase, guanylyl cyclase, the cGMP-gated channel, and NO synthase. The activity of several enzymes or channels is directly controlled by Ca2+ and does not involve calcium-binding proteins. These proteins are pyrophosphatase, protein kinase C and the cGMP-gated channel.
Koch
K W
KW
Institut für Biologische Informationsverarbeitung, Forschungszentrum Jülich, Germany.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000502:physiology*; D008027:Light; D010786:Photoreceptor Cells / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D002118:Calcium