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Updated: May 13, 2026

Preparation of Living Isolated Vertebrate Photoreceptor Cells for Fluorescence Imaging
Published on: June 22, 2011
A calcium-relay mechanism in vertebrate phototransduction
Karl-Wilhelm Koch1, Daniele Dell'orco
1Department of Neurosciences, Biochemistry Group, University of Oldenburg, Carl-von-Ossietzky-Strasse 9-11, D-26129 Oldenburg, Germany. karl.w.koch@uni-oldenburg.de
Abstract:
Calcium-signaling in cells requires a fine-tuned system of calcium-transport proteins involving ion channels, exchangers, and ion-pumps but also calcium-sensor proteins and their targets. Thus, control of physiological responses very often depends on incremental changes of the cytoplasmic calcium concentration, which are sensed by calcium-binding proteins and are further transmitted to specific target proteins. This Review will focus on calcium-signaling in vertebrate photoreceptor cells, where recent physiological and biochemical data indicate that a subset of neuronal calcium sensor proteins named guanylate cyclase-activating proteins (GCAPs) operate in a calcium-relay system, namely, to make gradual responses to small changes in calcium. We will further integrate this mechanism in an existing computational model of phototransduction showing that it is consistent and compatible with the dynamics that are characteristic for the precise operation of the phototransduction pathways.
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