Sociologist Stephan Lessenich becomes director of the IfS and professor in Frankfurt / “Further development of the IfS as a place for intellectual exchange”
The wait has come to an end: Sociologist Stephan Lessenich, who has been working until now at LMU Munich, has been appointed as professor at Goethe University and as director of the prestigious Institute for Social Research (IfS). The newly created cooperative professorship, which is linked with the directorship at the IfS, was made possible through the provision of special funds from the Federal State of Hessen. In this way, the university and the institute are coming closer together.
FRANKFURT. In 2018, Professor Axel Honneth retired as director of the Institute for Social Research, and since then Professor Ferdinand Sutterlüty has been temporarily in charge, heading the institute for two and a half years with tremendous dedication. Now there is a new constellation: With funding from the Federal State of Hessen, a professorship for “Social Theory and Social Research" is being set up at Goethe University – as a distinct cooperative professorship with the Institute for Social Research. The first incumbent has now been announced: Sociologist Professor Stephan Lessenich, currently at LMU Munich, has accepted the call to Frankfurt and will take up his new post on 1 July.
“I'm very pleased that Stephan Lessenich is coming to Frankfurt as professor and new director of the IfS," says Angela Dorn, Hessen's Minister of Science. “The importance of the work conducted by the Institute for Social Research has rarely been as manifest as it is right now. We need it to prevent the division of society. The IfS stands in a philosophical tradition that is not content with merely interpreting the world in different ways, but also wants to change it in the spirit of relentless questioning, constructive criticism and discursive debate. To be able to bolster this important role of the IfS by introducing top-class new management, we've happily raised the state's funding from 2021 onwards from a previous 615,000 to € 870,000 per year."
“It's a very pleasing development for Goethe University that the institute is now moving even closer to the university through the arrival of Stephan Lessenich. Professor Lessenich has made an international name for himself through his research and will give the university and the IfS even greater visibility worldwide," says Professor Enrico Schleiff, president of Goethe University. “Stephan Lessenich is very successful in combining sociological theory building and empirical research. “I'm convinced that the Frankfurt perspective will play a powerful role in future social debates," says Professor Birgit Blättel-Mink, dean of the Faculty of Social Sciences, commenting on the appointment. Jutta Ebeling, chairperson of the IfS's board of trustees: “I'm pleased that we're now placing the institute on a new footing and that we were able to recruit such a renowned scholar to head it. We're greatly indebted to Professor Sutterlüty, who for two and a half years has steered the institute with great dedication through a difficult period".
“It's a great honour for me to be asked to head an organisation that can look back on such a long tradition in critical social theory. Above all the sociological perspective is of growing significance in these times of social upheaval and socio-political agenda setting," says future IfS director Professor Stephan Lessenich. “I'd like to further develop the IfS as a lively place for intellectual exchange. Something else particularly close to my heart is the institute's internationalisation: The future of critical social research is conceivable only from the perspective of the globalised world," says Lessenich, describing his first ideas for the institute. He is greatly looking forward to Frankfurt too: “The city stands for a public with an exceptional interest in politics and culture, for a liberal culture of discussion and intellectual openness."
About Stephan Lessenich
Born in Stuttgart in 1965, Lessenich studied political science, sociology and history in Marburg from 1983 to 1989. He earned his doctoral degree in Bremen in 1993 and in 2002 received the venia legendi (authorisation to teach) in sociology at the University of Göttingen. His first professorship took him to the University of Jena, where he taught “Comparative Social and Cultural Analysis" and initiated the Research Group “Post-Growth Societies" funded by the German Research Foundation, together with Klaus Dörre and Hartmut Rosa. In 2014, Lessenich was called to the Chair for Social Developments and Structures at the Department of Sociology of LMU Munich, as successor to Ulrich Beck. From 2013 to 2017, Lessenich was chairperson of the German Sociological Association (GSA), he is co-editor of various scientific journals and book series and, among others, one of the speakers of the board of trustees of the think tank Institut Solidarische Moderne (ISM). He also plays a proactive role in social processes: He is, for example, a member of the scientific advisory board of Attac and in 2017 was co-founder of the “mut" party in order – as he says – to offer some opposition to the “shift in discourse to the right" in the wake of the long summer of migration.
How the new concept developed
In a press release by the Science Council (Wissenschaftsrat) concerning the evaluation of the institute in 2015, the “combination of socio-philosophical theory formation and empirical social research in the tradition of the history of ideas of the 'Frankfurt School'" practised at the IfS was called “unique worldwide". Its scientific accomplishments were rated “very good and in some areas even excellent". In addition, as the press release continued, the institute performed essential “interpretative work in the field of contemporary diagnostics" for a broader audience. However, it was also said at the time that “the institute's research work often suffers from a lack of opportunities for strategic development". The existence of “central research priorities" was repeatedly under threat, and the institute was excessively dependent on third-party funding. The Science Council recommended a more robust organisational substructure as well as a network of stable partnerships. The press release went on to say that in order to achieve this, among others the office of the director must be endowed with a permanent position financed from institutional funding and cooperation with Goethe University expanded and formalised.
In a complex process, a concept for such closer cooperation was developed in discussions with the university's executive board and in close consultation with the Hessian Ministry of Higher Education, Research, Science and the Arts, along with a new model for the management of the IfS. This process was supervised by Jutta Ebeling, former head of department and mayor of Frankfurt and, since 2018, chairperson of the IfS's board of trustees. She had already been instrumental in setting up the Professorship for Holocaust Studies in Frankfurt. Based on the model of this cooperative professorship with the Fritz Bauer Institute, the aim was to create a new professorship in cooperation with the IfS. This will now be hosted by the Institute of Sociology.
In the past, professors from Goethe University were appointed as directors of the IfS and performed this task more or less on an honorary basis, without anything about their work at the university changing in the process. With the new model, only 50 per cent of the respective professorship is at Goethe University, with the other half at the institute.
About the Institute for Social Research
The Institute for Social Research (IfS) at Goethe University is closely associated with the names Max Horkheimer and Theodor W. Adorno, but also Erich Fromm, Herbert Marcuse or Leo Löwenthal. Founded in 1923 with funds from patrons Hermann and Felix Weil as an institute for academic Marxism, with Max Horkheimer the IfS became the central research centre for critical theory. In the spring of 1933, the institute was closed by the Gestapo because of “subversive activities". Via circuitous routes, it managed to move to Columbia University in New York and continue its work in exile. After the war, the institute's closest circle – Adorno, Horkheimer and Pollock – returned to Frankfurt, and in 1951 the IfS was re-established at its present location. Since then, the Federal State of Hessen and the City of Frankfurt have secured its basic budget. In the course of its soon 100-year history, the IfS has left its mark on science and society in many ways. Professor Axel Honneth, the institute's last director, developed in his writings a normatively substantial social theory of recognition.
Images to download: http://www.uni-frankfurt.de/99435799
Caption: Stephan Lessenich appointed as sociology professor at Goethe University and as director of the Institute for Social Research (IfS).
(Picture 1: Dirk Bruniecki, Picture 2: private, Picture 3: LMU Munich)
Professor Stephan Lessenich
Scientists at Goethe University Frankfurt and the Center for European Policies Studies develop a simple formula to estimate the necessary rate of vaccinations
Despite rising infection numbers, contact restrictions could be avoided if the vaccination rate were fast enough. Professor Claudius Gros from Goethe University Frankfurt and Dr Daniel Gros from the Center for European Policies Studies in Brussels have developed a simple mathematical relation which allows to estimate the rate of vaccination necessary to maintain control of the pandemic without a lockdown and while avoiding overwhelming the health system and a spike in death rates. The study has been vetted and is forthcoming in Covid Economics.
FRANKFURT. As it has from the beginning, the pandemic continues to primarily affect older people. If the entire population of Germany became infected with SARS-CoV-2, statistically 1.5 million of those over 60 would die; among those under 60, the death toll would "only" be 75,000. This is why – in addition to certain particularly exposed population groups - vaccination strategies often prioritise the elderly with the aim of avoiding overburdening the health system with severe COVID-19 cases and high death rates. After all, vaccinating just a quarter of the population can prevent 95 percent of deaths.
Professor Claudius Gros from the Institute for Theoretical Physics at Goethe University Frankfurt and Dr Daniel Gros from the Center for European Policies Studies (CEPS) therefore focused on the older segment of the population when developing their vaccination formula. They show that COVID-19 fatalities are determined by three factors: The infection rate, the dependence of the risk on age, and the structure of the age pyramid. Germany, like almost all European countries, is particularly susceptible to the third wave: the average age of the population is high, the new mutant is highly infectious, but the vaccination rate is only slowly increasing. To keep the effects of the pandemic manageable, extensive contact restrictions are therefore necessary in order to keep infection rates low.
According to the two scientists, a rule of thumb can be used to determine the point at which it is possible to relax: They put the weekly increase in the number of infections in relation to the increase in vaccinations per week. Simplified, the relationship is as follows: If x percent more of the population falls ill per week, an additional x*f/100 percent of the population must be vaccinated in the same period. The factor f, which was f=2 at the beginning of the vaccination campaign, increases when part of the population has already been fully vaccinated. Currently we have f=6. This means that if the infection incidence increases by x=20 percent per week, 20*6/100=1.2% of the population would have to be additionally (fully) vaccinated. This applies to the vaccination doses administered by age. It should be taken into account that two vaccination doses are necessary for complete immunisation.
Dr Daniel Gros explains: "Given the low current vaccination rate, the 7-day incidence per week should not increase by more than 13 to 16 percent to prevent the health system from being overwhelmed. Over the past weeks, however, infection rates have increased by 25 percent, making extensive contact restrictions inevitable, otherwise aggressive mutants are likely to spread."
Prof. Claudius Gros says: "The relation we developed allows for a simple and quick estimate of how quickly we would need to vaccinate to keep the consequences of the pandemic for the health system manageable. Unfortunately, we have failed to incentivise pharmaceutical companies to rapidly scale up production, which is costly and resource-intensive, for example through higher prices for an earlier production of vaccine doses. Therefore, as we predicted in an earlier paper, companies have opted for a slow linear increase in production. From a business point of view, this is cost-effective, but it results in us not having sufficient amounts of vaccine available fast enough."
Publication: Claudius Gros and Daniel Gros, „How fast must vaccination campaigns proceed in order to beat rising Covid-19 infection numbers?“ in: Covid Economics (in press), https://arxiv.org/abs/2103.15544
Further information: Professor Claudius Gros Institute for Theoretical Physics Goethe University Frankfurt email@example.com
Editor: Dr. Markus Bernards, Science Editor, PR & Communication Department, Tel: -49 (0) 69 798-12498, Fax: +49 (0) 69 798-763 12531, firstname.lastname@example.org
11 telescopes around the world combined to research the core of a galaxy 55 million light-years away
Scientists of the Event Horizon Telescope (EHT) collaboration - among them astrophysicist Luciano Rezzolla and his team from Goethe University Frankfurt - have revealed today a new view of the massive object at the centre of the M87 galaxy: how it looks in polarised light. This is the first time astronomers have been able to measure polarisation, a signature of magnetic fields, this close to the edge of a black hole. The observations are key to explaining how the M87 galaxy, located 55 million light-years away, is able to launch energetic jets from its core – jets, that are about one million light years large.
FRANKFURT. Luciano Rezzolla, Professor of Theoretical Astrophysics at Goethe University Frankfurt, says: “Understanding what powers relativistic jets in galaxies is a long-standing open question in astrophysics. The jets in M87 are enormous and they would cover 10 per cent of our galaxy, for example. The challenging observations from the ETH telescopes, combined with the theoretical simulations carried out in Frankfurt, are now providing essential information on comparatively small length-scales: For the first time we are looking at what the magnetic field looks like that close to the black hole.
“We are now seeing the next crucial piece of evidence to understand how magnetic fields behave around black holes, and how activity in this very compact region of space can drive powerful jets that extend far beyond the galaxy," says Monika Moscibrodzka, Coordinator of the EHT Polarimetry Working Group and Assistant Professor at Radboud University in the Netherlands.
On 10 April 2019, scientists released the first ever image of a black hole, revealing a bright ring-like structure with a dark central region — the black hole's shadow. Since then, the EHT collaboration has delved deeper into the data on the supermassive object at the heart of the M87 galaxy collected in 2017. They have discovered that a significant fraction of the light around the M87 black hole is polarised.
“This work is a major milestone: the polarisation of light carries information that allows us to better understand the physics behind the image we saw in April 2019, which was not possible before," explains Iván Martí-Vidal, also Coordinator of the EHT Polarimetry Working Group and GenT Distinguished Researcher at the University of Valencia, Spain. He adds that “unveiling this new polarised-light image required years of work due to the complex techniques involved in obtaining and analysing the data."
Light becomes polarised when it goes through certain filters, like the lenses of polarised sunglasses, or when it is emitted in hot regions of space that are magnetised. In the same way polarised sunglasses help us see better by reducing reflections and glare from bright surfaces, astronomers can sharpen their vision of the region around the black hole by looking at how the light originating from there is polarised. Specifically, polarisation allows astronomers to map the magnetic field lines present at the inner edge of the black hole.
“The newly published polarised images are key to understanding how the magnetic field allows the black hole to 'eat' matter and launch powerful jets," says EHT collaboration member Andrew Chael, a NASA Hubble Fellow at the Princeton Center for Theoretical Science and the Princeton Gravity Initiative in the US.
The bright jets of energy and matter that emerge from M87's core and extend at least 5000 light-years from its centre are one of the galaxy's most mysterious and energetic features. Most matter lying close to the edge of a black hole falls in. However, some of the surrounding particles escape moments before capture and are blown far out into space in the form of jets.
Astronomers have relied on different models of how matter behaves near the black hole to better understand this process. But they still don't know exactly how jets larger than the galaxy are launched from its central region, which is as small in size as the Solar System, nor how exactly matter falls into the black hole. With the new EHT image of the black hole and its shadow in polarised light, astronomers managed for the first time to look into the region just outside the black hole where this interplay between matter flowing in and being ejected out is happening.
The observations provide new information about the structure of the magnetic fields just outside the black hole. The team found that only theoretical models featuring strongly magnetised gas can explain what they are seeing at the event horizon.
“The observations suggest that the magnetic fields at the black hole's edge are strong enough to push back on the hot gas and help it resist gravity's pull. Only the gas that slips through the field can spiral inwards to the event horizon," explains Jason Dexter, Assistant Professor at the University of Colorado Boulder, US, and coordinator of the EHT Theory Working Group.
To observe the heart of the M87 galaxy, the collaboration linked eight telescopes around the world, to create a virtual Earth-sized telescope, the EHT. The impressive resolution obtained with the EHT is equivalent to that needed to measure the length of a credit card on the surface of the Moon.
This allowed the team to directly observe the black hole shadow and the ring of light around it, with the new polarised-light image clearly showing that the ring is magnetised. The results are published today in two separate papers in The Astrophysical Journal Letters by the EHT collaboration. The research involved over 300 researchers from multiple organisations and universities worldwide.
"The EHT is making rapid advancements, with technological upgrades being done to the network and new observatories being added. We expect future EHT observations to reveal more accurately the magnetic field structure around the black hole and to tell us more about the physics of the hot gas in this region," concludes EHT collaboration member Jongho Park, an East Asian Core Observatories Association Fellow at the Academia Sinica, Institute of Astronomy and Astrophysics in Taipei.
The Event Horizon Collaboration, Kazunori Akiyama et al.: First M87 Event Horizon Telescope Results VII: polarization of the ring. Astrophysical Journal Letters, 910, L12 (2021) DOI 10.3847/2041-8213/abe71d (ApJL 910, L12)
The Event Horizon Collaboration: Kazunori Akiyama et al.: First M87 Event Horizon Telescope Results VIII: Magnetic Field Structure Near The Event Horizon. Astrophysical Journal Letters, 910, L13 (2021) DOI 10.3847/2041-8213/abe4de (ApJL 910, L13)
A view of the M87 supermassive black hole in polarised light: The Event Horizon Telescope (EHT) collaboration, who produced the first ever image of a black hole released in 2019, has today a new view of the massive object at the centre of the Messier 87 (M87) galaxy: how it looks in polarised light. This is the first time astronomers have been able to measure polarisation, a signature of magnetic fields, this close to the edge of a black hole. This image shows the polarised view of the black hole in M87. The lines mark the orientation of polarisation, which is related to the magnetic field around the shadow of the black hole.
Credit: EHT Collaboration
http://www.uni-frankfurt.de/99324167 (Animated GIF - Download)
Observation and Theory Image: Transition animation showing the observed polarization image and a best-fit theory image. Credit: S. Issaoun, M. Mościbrodzka with Polarimetry WG and OWG
Zoom into the heart of galaxy M87 – The video starts with a view on the ALMA telescope which is part of the Event Horizon Telescope, and zooms into the heart of galaxy M87. In the core, the first image of a black hole can be seen, the picture was produced in 2019. Then the new image follows which shows the supermassive object in polarised light. It is the first time that astronomers could detect polarisation as a signature of magnetic fields so closely to the event horizon of a black hole. Credit: ESO/L. Calçada, Digitized Sky Survey 2, ESA/Hubble, RadioAstron, De Gasperin et al., Kim et al., EHT Collaboration. Music: Niklas Falcke
Polarized Light: Light is an oscillating electromagnetic wave. If the waves have a preferred direction of oscillation, they are polarized. In space, moving hot gas, or 'plasma', threaded by a magnetic field emits polarized light. The polarized light rays that manage to escape the pull of the black hole travel to a distant camera. The intensity of the light rays and their direction are what EHT collaboration observes with the Event Horizon Telescope.
Credit: © EHT Collaboration and Fiks Film
Black holes are enveloped in plasma. This plasma has magnetic fields—areas where magnetism affects how matter moves—threaded throughout. As the magnetic field grows stronger, it changes shape and the polarized light EHT collaboration measures exhibits different patterns.
Credit: © EHT Collaboration and Crazybridge Studios
http://www.uni-frankfurt.de/99324248 (Image - Download)
View of the M87 supermassive black hole and jet in polarised light. This composite image shows three views of the central region of the Messier 87 (M87) galaxy in polarised light. The galaxy has a supermassive black hole at its centre and is famous for its jets that extend far beyond the galaxy. One of the polarised-light images, obtained with the Chile-based Atacama Large Millimeter/submillimeter Array (ALMA), shows part of the jet in polarised light, with a size of 6000 light years from the centre of the galaxy. The other polarised light images zoom in closer to the supermassive black hole: the middle view covers a region about one light year in size and was obtained with the National Radio Astronomy Observatory's Very Long Baseline Array (VLBA) in the US. The most zoomed-in view was obtained by linking eight telescopes around the world to create a virtual Earth-sized telescope, the Event Horizon Telescope or EHT. This allows astronomers to see very close to the supermassive black hole, into the region where the jets are launched. The lines mark the orientation of polarisation, which is related to the magnetic field in the regions imaged. The ALMA data provides a description of the magnetic field structure along the jet. Therefore the combined information from the EHT and ALMA allows astronomers to investigate the role of magnetic fields from the vicinity of the event horizon (as probed with the EHT on light-day scales) to far beyond the M87 galaxy along its powerful jets (as probed with ALMA on scales of thousands of light-years). The values in GHz refer to the frequencies of light at which the different observations were made. The horizontal lines show the scale (in light years) of each of the individual images. Credit: EHT Collaboration; ALMA (ESO/NAOJ/NRAO), Goddi et al.; VLBA (NRAO), Kravchenko et al.; J. C. Algaba, I. Martí-Vidal
Prof. Dr. Luciano Rezzolla
Chair of Theoretical Astrophysics
Institute for Theoretical Physics
Goethe University Frankfurt
Phone: +49 69 798-47871 / 47879
A research team from the universities of Frankfurt and Mainz shines a light on new global players in Africa and Asia.
When Korean pop bands such as boy group BTS reach millions of fans worldwide, and when films and music from Nigeria are seen and heard across the globe: What does this mean for the production of culture? And how does it affect our perception of cultural spaces? An interdisciplinary research team that brings together Economics, African Studies, Korean Studies, Sinology, Cultural Anthropology and Film Studies will look for answers to these questions at Goethe University Frankfurt and Johannes Gutenberg University Mainz over the next three years. With € 2.1 million in funding from Germany's Federal Ministry of Education and Research (BMBF), CEDITRAA (“Cultural Entrepreneurship and Digital Transformation in Africa and Asia") will study the emergence of what Pakistani writer Fatima Bhutto calls the “new world order of cultural production", which Hollywood and Europe no longer dominate.
FRANKFURT. In the early 1990s, Kenneth Nnebue, a Nigerian seller of home video equipment, picked up his VHS camera and changed the course of film history. To boost sales of VHS recorders, he produced his own film. “Living in Bondage" sold around 750,000 copies and spawned numerous imitations. Practically out of nowhere, Nigeria built up a film industry with global outreach, now popularly known as “Nollywood", which today ranks second only to India in terms of annual film output. “The rise of Nigeria and the global success of Korean films, TV dramas and pop music in the new millennium show that a fundamental shift is taking place in cultural production and reception across the globe," says Vinzenz Hediger, project leader and professor of cinema studies at Goethe University.
Digitalisation is one of the driving forces behind this transformation and the emergence of the “new world order of cultural production". The researchers in Frankfurt and Mainz will study how cultural industries with transregional audiences contribute to the economic growth and soft power of their regions and countries of origin. They will also examine the role of regional resources in the creative work of artists in music and film. “One open question," says economics professor Cornelia Storz, “is whether entrepreneurs in digital industries may, in fact, be more dependent on local resources than their global reach and outlook might suggest." Particular attention will be paid to how producers in music and film draw on cultural heritage to produce innovative formats which resonate with larger, global contexts.
The CEDITRAA research group will address these issues through a series of case studies on music and film in Africa and Asia. Here, the Archiv der Musik Afrikas (AMA), the Archive for the Music of Africa, at Johannes Gutenberg University Mainz will play a particularly important role. For the case studies dedicated to music and copyright issues, the AMA is an invaluable resource – particularly for research on “Afrobeats" and other forms of sub-Saharan pop music, which recombines different gernes in innovative new ways. “This music has many fans in the Global North as well," says Matthias Krings, professor of cultural anthropology and the popular culture of Africa in Mainz. “Among them is Beyoncé, who created a sensation with her 2020 album 'Black Is King', not least because it featured guest appearances by Afrobeats stars such as Burna Boy, Wizkid, Tiwa Savage and Yemi Alade."
The parts of the project dedicated to Asia will study the circulation and reception of Korean popular culture in Asia and Africa and benefit from close collaboration with non-university partners such as the Korean Film Archive. The case study dedicated to Taiwan will focus on the Kaohsiung Film Festival and its close ties to the Korean film industry. In Nigeria, the project will collaborate closely with the Nollywood Studies Centre at the Pan-Atlantic University in Lagos, a research institute with closes ties to the film and music industries in Nigeria. The Nigerian part of the project will include a PhD position at the Pan-Atlantic University.
Funded by Germany's Federal Ministry of Education and Research, the project will bring together for the first time the area studies research centres in the Rhine-Main University Alliance in a joint research initiative – the Centre for Interdisciplinary African Studies (ZIAF) and the Interdisciplinary Centre for East Asian Studies (IZO) at Goethe University and the Centre for Intercultural Studies (ZIS) at Johannes Gutenberg University Mainz.
The research project enhances the profile of area studies in the Rhine-Main University Alliance through its close connection to teaching. Project results will be used in teaching in several degree programmes, most notably the bachelor's degree programme “African Languages, Media, and Culture", which is being prepared as a joint programme of Goethe University Frankfurt and Johannes Gutenberg University Mainz.
Caption: Global popstars with an army of Twitter fans: K-pop superstars BTS (c) Kim-Hee Chu / dpa
Professor Vinzenz Hediger, Professor of Cinema Studies, Goethe University: email@example.com
Professor Claudia Storz, Chair for the Study of Economic Institutions, Innovation and East Asian Development, Goethe University: firstname.lastname@example.org
Professor Matthias Krings, Professor of Anthropology and Popular Culture of Africa, Johannes Gutenberg University Mainz: email@example.com
Clustering of receptors can have the same effect as binding a signaling molecule – receptor clusters can direct cell movement
Whether we smell, taste or see, or when adrenaline rushes through our veins, all of these signals are received by our cells via a specific group of receptor proteins called G protein-coupled receptors, which transmit signals to the inside of the cell. Biochemists at Goethe University Frankfurt and the University of Leipzig have now discovered that such receptors can also produce signals even in the absence of an external stimulus: It is apparently sufficient for certain receptors if many of them are clustered at the cell surface. (Science, doi/10.1126/science.abb7657)
FRANKFURT. Our body consists of 100 trillion cells that communicate with each other, receive signals from the outside world and react to them. A central role in this communication network is attributed to receiver proteins, called receptors, which are anchored at the cell membrane. There, they receive and transmit signals to the inside of the cell, where a cell reaction is triggered.
In humans, G protein-coupled receptors (GPC receptors) represent the largest group of these receptor molecules, with around 700 different types. The research of the Frankfurt and Leipzig scientists focused on a GPC receptor that serves as a receptor for the neuropeptide Y in cells and is accordingly called the Y2 receptor. Neuropeptide Y is a messenger substance that primarily mediates signals between nerve cells, which is why Y2 receptors are mainly present in nerve cells and among other activities trigger the formation of new cell connections.
In the laboratory, the researchers engineered cells, which had approx. 300,000 Y2 receptors on their surface and were grown on specifically developed, light-sensitive matrices. Each of the Y2 receptors was provided with a small molecular "label". Once the scientists created a spot of light with a fine laser beam on the cell surface, the Y2 receptor under this spot were trapped via the molecular label to the exposed matrix in such a way that the Y2 receptors moved closely together to form an assembly known as a cluster. The whole reaction could be immediately observed at the defined spot and within a few seconds.
Robert Tampé from the Institute of Biochemistry at Goethe University Frankfurt
explains: "The serendipity about this experiment is that the clustering of
receptors triggers a signal that is similar to that of neuropeptide Y. Solely
by the clustering, we were able to trigger cell movement as a reaction of the
cell. The laser spots even allowed us to control the direction of the cell
movement." As the light-sensitive lock-and-key pairs utilized are very
small compared to the receptors, the organization of the receptors in the cell
membrane can be controlled with high precision using the laser spot. "This
non-invasive method is thus particularly well suited to study the effects of
receptor clustering in living cells," Tampé continues. "Our method
can be used to investigate exciting scientific questions, such as how receptors
are organized in networks and how new circuits are formed in the brain."
M. Florencia Sánchez, Sylvia Els-Heindl, Annette G. Beck-Sickinger, Ralph
Wieneke, Robert Tampé: Photo-induced receptor confinement drives
ligand-independent GPCR signaling. Science abb7657
DOI: 10.1126/science.abb7657; https://science.sciencemag.org/lookup/doi/10.1126/science.abb7657
Caption Image: Laser spots activate very small synthetic lock-and-key pairs in a matrix to create receptor clusters in the cell membrane. This ligand-independent activation triggers calcium signaling and increased cell motility. (Graphic copyright: M. Florencia Sánchez & Robert Tampé, Goethe University Frankfurt.)
Caption Movie: Upon irradiation with laser light (white rings), receptors cluster in the cell (light green circles). Thereupon, the cell moves into the direction of the receptor clusters. (Copyright: M. Florencia Sánchez & Robert Tampé, Goethe University Frankfurt). Reprinted with permission from M. F. Sánchez et al., Science 10.1126/science.abb7657(2021).