Tuning wavelength and G protein specificity of Melanopsin for optogenetic control of G protein signaling pathways.
1) Klaus Gerwert (PI; University of Bochum), coworker:
2) Stefan Herlitze (PI; University of Bochum), coworker:
Tuning wavelength and G protein specificity of bistable Melanopsin for optogenetic control of G protein signaling pathways.
Our goal is to create optogenetic tools for independent control of intracellular G protein signals activated by the Gi/o and Gs but in particular the Gq/11 and G12/13 pathway. These tools will be established using vertebrate melanopsin, as the light-activated G protein coupled receptor (GPCR), which activates Gq/11 and Gi/o pathways in neurons and heterologous expression systems. Computer models (Gerwert lab) will predict amino acid position critical for wavelength specificity, bistabililty and G protein selectivity and the functional analysis (Herlitze lab) of amino acid changes at predicted position using electrophysiological recordings will feed back into new working models of melanopsin and its G protein selectivity. Vertebrate melanopsin as a bistable pigment is preferable over commonly used opsins to control G protein pathways in particular for highly-repetitive in vivo applications, because it can be switched on and off by two different wavelength of visible light. In addition, sustained G protein signals can be activated by short light pulses, reducing phototoxicity. These tools will be applicable for controlling every GPCR coupling to the common G protein pathways, such as dopamine, adreno, metabotropic glutamate, histamine or orexin receptor pathways without change in signal kinetics. Because of our long-standing interest in serotonin, we will tailor these tools to specifically control G protein signals in 5HT receptor signaling domains. The ultimate goal is to control two signaling pathways simultaneously, but independently by two different wavelength of light to understand how G protein signals synergistically and/or independently act to modulate cell function and behavior.
Logic of interaction:
In order to perform these experiments we have assembled a team of two experts on the development of optogenetic tools (Herlitze) and computational modeling of protein structures (Gerwert).
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