Tool for switching proteins on and off
Thanks to a new tool that can allow controlling several proteins with the light of different wavelengths, at once. By using light pulses, optogenetic tools or the light-sensitive proteins can be switched on and off which triggers specific cellular processes.
At Ruhr-Universität Bochum (RUB), a research team has characterized the protein parapinopsin, a new optogenetic tool, which, with very weak and short light signals, can be switched on and off. When compared to the wavelengths used by other known optogenetic tools, the excitation wavelengths required for this purpose differ greatly. As a result, simultaneously using two such tools is possible. In the cover story of the journal ChemBioChem, these findings were reported by Professor Stefan Herlitze and Professor Klaus Gerwert, the team leads.
Protein from a fish
Researchers now used the protein parapinopsin while they had previously mainly focused on investigating the protein melanopsin. From the Department of General Zoology and Neurobiology at RUB, Dennis Eickelbeck explains, ” A light-sensitive receptor from the pineal organ of the Japanese lamprey, this tool is an opsin, i.e. a G protein-coupled.” To analyze the receptor, the researchers used electrophysiological and optical methods. The first 3D structural model of parapinopsin using computer-aided methods was created by the researchers at the Department of Biophysics by combining these experimental approaches.
Dr. Till Rudack elaborates saying, “Formulating hypotheses on the dynamics of the complex molecular mechanisms of parapinopsin using biomolecular simulations will be enabled by this structural model in the future.”
The scientists demonstrated that a specific G protein signaling pathway can be switched on or off with light of different wavelengths using lamprey parapinopsin – which the scientists named “UV-Lamp”, in the course of this RUB collaboration. Dennis Eickelbeck says, “To switch on, we use UV light and to switch off, we use light in the blue wavelength range.”
Simultaneously with other tools
The UV-Lamp can theoretically be used simultaneously with other optogenetic tools since the wavelength range used for switching on is far in the UV range. Dennis Eickelbeck explains, “for instance, we could control a signaling pathway using UV-Lamp having UV and blue light and for another signaling pathway, we can use another optogenetic tool with red and green light, all in the same experiment.”
The protein being extremely light-sensitive is of equal interest to the researchers. Consequently, for the continuous control of the corresponding signaling pathway, extremely short light pulses of low intensity in the range of milliseconds are sufficient. Thus, there are reduced harmful potential effects of light radiation on the cells.”
