Signal transmission

  • A Nano-Roundabout for Light

    Functional principle of a nano-roundabout.  © TU Wien

    At TU Wien, it was possible to create a nanoscale optical element that regulates the flow of light particles at the intersection of two glass fibers like a roundabout. A single atom was used to control the light paths. Just like in normal road traffic, crossings are indispensable in optical signal processing. In order to avoid collisions, a clear traffic rule is required. A new method has now been developed at TU Wien to provide such a rule for light signals. For this purpose, the two glass fibers were coupled at their intersection point to an optical resonator, in which the light circulates and behaves as in a roundabout. The direction of circulation is defined by a single atom coupled to the resonator. The atom also ensures that the light always leaves the roundabout at the next exit. This rule is still valid even if the light consists merely of individual photons. Such a roundabout will consequently be installed in integrated optical chips – an important step for optical signal processing.

  • Biological system with light switch: new findings from Graz

    Schematic representation of the illumination of the sensor domain of a photo-receptor and the molecular propagation of the light signal to the effector (in red on the right-hand edge of the image). © TU Graz/IBC

    For the first time ever, researchers at TU Graz and the Medical University of Graz have managed to functionally characterise the three-dimensional interaction between red-light receptors and enzymatic effectors. The results, with implications for optogenetics, have been published in Science Advances. The aim of optogenetics is to control genetically modified cells using light. A team of Graz scientists led by Andreas Winkler from the Institute of Biochemistry at TU Graz have set a milestone in the future development of novel red-light regulated optogenetic tools for targeted cell stimulation.

  • Cholesterol important for signal transmission in cells

    CXCR4 receptor which belongs to a group known as G protein-coupled receptors. FAU/Rainer Böckmann

    Cholesterol can bind important molecules into pairs, enabling human cells to react to external signals. Researchers at Friedrich-Alexander University Erlangen-Nürnberg’s (FAU) Chair of Biotechnology have studied these processes in more detail using computer simulations. Their findings have now been published in the latest volume of the journal PLOS Computational Biology*. FAU researchers Kristyna Pluhackova and Stefan Gahbauer discovered that cholesterol strongly influences signal transmission in the body. Their study focused on the chemokine receptor CXCR4, which belong to a group known as G protein-coupled receptors (GPCRs). These receptors sense external stimuli such as light, hormones or sugar and pass these signals on to the interior of the cell which reacts to them. CXCR4 normally supports the human immune system. However, it also plays an important role in the formation of metastases and the penetration of HIV into the cell interior.

  • Coupled Proteins

    The image portrays which G-proteins bind to particular G-protein coupled receptors (GPCRs) and in turn how these are related to signalling events. © Thomas Splettstoesser (www.sci-style.com)

    Researchers from Heidelberg University and Sendai University in Japan used new biotechnological methods to study how human cells react to and further process external signals. They focussed on the interaction between so-called G-proteins – the “mediators” of signal transmission – and the receptors known as GPCRs, which trigger signal processes.

  • How enzymes communicate

    Electro-chemical coupling through protein super complexes: The calcium channel (Cav2) delivers calcium ions (Ca2+) that activate the enzyme NO synthase (NOS) for generation of the messenger NO. Source: Bernd Fakler

    Freiburg scientists explain the cell mechanism that transforms electrical signals into chemical ones. The enzymes nitric oxide (NO) synthase (NOS1) and protein kinase C (PKC) play an important role in a variety of signal transfer processes in neurons of the brain, as well as in many cell types of other organs. Together with Prof. Dr. Bernd Fakler at the Institute of Physiology at the University of Freiburg, the scientists Dr. Cristina Constantin and Dr. Catrin Müller have shown for the first time that enzymes can be activated under physiological conditions through sole electrical stimulation of the cell membrane. Protein super complexes that rapidly transform electrical signals at the cell membrane into chemical signal processes inside the cell emerge through direct structural interaction of both enzymes with voltage-gated calcium channels. The researchers have presented their work in the current issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS).

  • New Collaborative Research Center on a Fundamental Signaling Pathway in Development and Disease

    Signal Transduction Pathways Model.

    New Collaborative Research Center on a Fundamental Signaling Pathway in Development and Disease
    DFG supports interdisciplinary research network at Heidelberg University with approximately 8,5 million euros

    A new Collaborative Research Centre (CRC) will investigate the function of a fundamental cellular signaling pathway. Funded by the German Research Foundation (DFG), the CRC will start its work at Heidelberg University. After successful review, the DFG approved approximately 8,5 million euros in funding for the next four years. Prof. Dr Thomas Holstein of the Centre for Organismal Studies (COS) is the spokesperson for CRC 1324, “Mechanisms and functions of WNT signaling”. The research will focus on Wnt proteins which control the central processes of embryonic development, cell differentiation, and the development of tumours.