Role of calcium ions in vertebrate phototransduction

In the recent years several new regulatory calcium-binding proteins were identified in vertebrate photoreceptor cells. Calcium ions can regulate different stages of visual transduction acting through calcium-binding proteins. It is also accepted that Ca(2+)-mediated feedback pathways underlie the light adaptation mechanisms in photoreceptor cells. This article describes the role of calcium ions in the cascade of enzymatic reactions contributing to the vertebrate rod cell phototransduction and to light adaptation.