Scientists have examined a protein that will find application in optogenetics and could be used to control muscle and neuronal cells. The paper on the light-sensitive NsXeR protein of the xenorhodopsin class was published in Science Advances by the international team of researchers from MIPT, Forschungszentrum Jülich, and Institut de Biologie Structurale.
Why it matters
Researchers described a new optogenetic tool -- a protein called NsXeR, which belongs to the class of xenorhodopsins. When exposed to light, it can activate individual neurons, making them send set signals to the nervous system. Apart from applications in nervous system research, xenorhodopsins may also take over muscle cell control.
Credit: MIPT Press Office
Optogenetics is a new technique that uses light to control neurons or muscle cells in living tissue. It has found wide application in nervous system studies. Optogenetic manipulations are so precise that they make it possible to control individual neurons by switching certain information transfer pathways on or off. Similar methods are also used to partially reverse eyesight or hearing loss as well as to control muscle contractions.
The main tools of optogenetics are light-sensitive proteins that are intentionally inserted into particular cells. After the insertion, the protein becomes attached to the cell surface and moves ions across the membrane upon exposure to light.
Thus, in a modified neuron cell, a correctly chosen light impulse may activate a neural signal or, on the contrary, suppress all the signals, depending on which protein is used. By activating signals from individual neurons, it is possible to imitate the functioning of certain brain regions -- a technique that modulates the behavior of the organism under study. If such proteins are inserted in muscle cells, an external signal can tense or relax them.
The authors of the paper, which was published in Science Advances, described a new optogenetic tool -- a protein called NsXeR, which belongs to the class of xenorhodopsins. When exposed to light, it can activate individual neurons, making them send set signals to the nervous system.
Apart from applications in nervous system research, xenorhodopsins may also take over muscle cell control. To activate these cells, it is preferable that calcium ion transport be blocked, because alterations in the ion concentration can affect them. When using proteins that transport various positive ions (such as calcium) nonselectively, undesirable side effects are likely to appear.
The discovered protein helps to bypass uncontrolled calcium translocation: It is selective and pumps nothing but the protons into the cell. Because of this selectivity, it has a considerable advantage over its chief rival channelrhodopsin, which is being extensively used in research but does not discriminate between positively charged ions.
What is more, xenorhodopsin acts as a reliable pump, transporting protons both into and out of the cell regardless of their concentration, whereas channelrhodopsin only allows ions to move from an area of higher concentration to an area of lower concentration.
In both cases a positive charge inflow into an excitable cell reduces the tension between its inner and outer membrane surfaces. Such membrane depolarization generates a nerve or muscle impulse. The ability to induce such an impulse by pumping nothing but protons will reduce possible side effects during research.
"So far we have all the necessary data on how the protein functions. This will become the basis of our further research aimed at optimizing and adjusting the protein parameters to the needs of optogenetics," says Vitaly Shevchenko, the lead author of the paper and a staff member at the MIPT Laboratory for Advanced Studies of Membrane Proteins.
This research was supported ERA.Net RUS PLUS and the Ministry of Education and Science of the Russian Federation (project ID 323, RFMEFI58715X0011).
Asya Shepunova | EurekAlert!
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy