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Updated: May 11, 2026

Optogenetic Signaling Activation in Zebrafish Embryos
Published on: October 27, 2023
The guanylate cyclase signaling system in zebrafish photoreceptors
1Biochemistry Group, Faculty VI, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg, Germany. karl.w.koch@uni-oldenburg.de
Abstract:
Zebrafish express in the retina a large variety of three different membrane-bound guanylate cyclases and six different guanylate cyclase-activating proteins (zGCAPs) belonging to the family of neuronal calcium sensor proteins. Although these proteins are predominantly localized in rod and cone photoreceptor cells of the retina, they differ in their spatial-temporal expression profiles. Further, each zGCAP has a different affinity for Ca(2+) and displays different Ca(2+)-sensitivities of guanylate cyclase activation. Thus, zGCAPs operate as cytoplasmic Ca(2+)-sensors that sense incremental changes of cytoplasmic Ca(2+)-concentration in rod and cone cells and control the activity of their target guanylate cyclases in a Ca(2+)-relay mode fashion.
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