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News Archive

Protein Crumbs as the traffic guidance system of the cell membrane


A trouble-free transport mechanism within membranes is essential for the function of polarized epithelial cells. Defects in membrane transport are associated with a variety of diseases, including immune syndromes, deafness, neuronal degeneration and cancer. A group of researchers from the Biotechnology Center of the TU Dresden (BIOTEC) and the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), have therefore studied how polarity proteins regulate intracellular membrane trafficking.

Using the salivary gland of Drosophila larvae, they showed that the key polarity protein Crumbs organizes the apical membrane trafficking machinery. The results indicate that Crumbs is essential for membrane homeostasis, the physiological function of a secretory gland and the development of the larvae by affecting the feeding behaviour of the animals. Although Crumbs is already a known key determinant of the apical plasma membrane, very little is known about the mechanism behind it. This work provides a molecular mechanism that explains how Crumbs controls apical membrane organization and identity.

The study provides an attractive experimental model to analyse the molecular mechanisms behind the maintenance of polarized membranes in vivo. This can also be useful to understand how cells control the transport and delivery of certain cargoes under physiological and pathological conditions. For example, the results suggest that Crumbs and the lipid regulator Pten may be involved in Microvillus Inclusion Disease (MVID), a fatal genetic disease characterized by the lack of microvilli on the surface of enterocytes. Interesting follow-up research would be whether the molecular mechanism described here is also relevant in the clinical picture of human diseases like retinal degeneration associated with mutations in the human gene CRUMBS1, which is estimated to affect 80,000 people worldwide.

Publication in eLife: https://elifesciences.org/articles/50900

Schematic representation of Crumbs-dependent regulation of apical secretion in salivary glands cells © Ivana Henry, credit BioDATA Clarity studio

Graduation of Master’s students


After two years of interdisciplinary study and research, 72 students of the three international Master’s programs at the Center for Molecular and Cellular Bioengineering (CMCB) completed their studies successfully in September 2019. The graduation ceremony took place on October 30th. The Master’s students received their certificates from Prof. Marius Ader, Prof. Michael Schlierf and Prof. Simon Alberti. In the program „Molecular Bioengineering“, 32 students were graduating and 20 students in „Nanobiophysics“ as well as in „Regenerative Biology and Medicine“.

The three international Master Programs at the BIOTEC, CRTD and B CUBE include four terms and are held in English. The application for the winter term 2020/21 will start in April 2020.

Find more information here.

Graduation ceremony © Friederike Braun

Microbes as a possible key to biological pest control


Progress in interdisciplinary research project on fruit flies

Since 2018, the DFG-funded interdisciplinary research team FOG 2682 led from the Biotechnology Center (BIOTEC) at the TU Dresden has been investigating the basic principles of insect adaptation to temperature fluctuations in the environment. The project group with scientists from seven different research institutions in Germany found out that insects have a temperature-dependent feeding behaviour. It is only through this behaviour that they can adapt their organism to environmental factors. Moreover, the quality of the food and the microbes involved are also temperature-dependent. Manipulation of the microbes could therefore be a natural method of pest control.

Find here the complete press release.

Scientific model fruit fly (Drosophila melanogaster, above) and the plant pest cherry vinegar fly (Drosophila suzukii, below) © BIOTEC

A new method of tooth repair? Scientists uncover mechanisms that could help future dental treatment


Researchers from TU Dresden’s Biotechnology Center teamed up with international scientists that led to the discovery of a new stem cell population in the front teeth of mice

Stem cells hold the key for tissue engineering, as they develop into specialised cell types throughout the body including in teeth. An international team of researchers, including scientists from the Biotechnology Center of the TU Dresden (BIOTEC), has found a new mechanism that could offer a potential new solution to tooth repair. They discovered a new population of mesenchymal stromal cells in a continuously growing mouse incisor model. They have shown that these cells contribute to the formation of dentin, the hard tissue that covers the main body of a tooth. Importantly, the work showed that when these stem cells are activated, they send signals back to the mother cells of the tissue to control the number of cells produced, through a molecular gene called Dlk1. This study is the first to show that Dlk1 is vital for this process to work. In the same study, the researchers also demonstrated that Dlk1 can enhance stem cell activation and tissue regeneration in a wound healing model. This mechanism could provide an innovative solution for tooth repair, addressing problems such as tooth decay, crumbling and trauma treatment. Further studies are needed to validate the results for clinical applications to determine the appropriate duration and dose of treatment.

The study was led by Dr Bing Hu of the Peninsula Dental School of the University of Plymouth, UK. Co-authors were research group leader Dr. Denis Corbeil and his colleague Dr. Jana Karbanová from BIOTEC. "The discovery of this new population of stromal cells was very exciting and has enormous potential in regenerative medicine," says Dr. Denis Corbeil.

Publication: Nature Communications “Transit Amplifying Cells Coordinate Mouse Incisor Mesenchymal Stem Cell Activation”

Research Team Dr. Denis Corbeil

TU Dresden retains its title as University of Excellence


Everybody at our university is excited: TU Dresden has received permanent funding as a University of Excellence! This was announced on Friday afternoon 19. July 2019 at a press conference given by the German Council of Science and Humanities. The decision was made by the Excellence Commission, comprised of the Committee of Experts as well as federal and state ministers of research. TU Dresden is one of a total of 11 Universities of Excellence in Germany and the only University of Excellence in the eastern German federal states (except Berlin).

At TU Dresden, the result was met with euphoric applause. In response, the Rector, Prof. Hans Müller-Steinhagen, emphasised the importance of this title for the strategic development of the university: "We have been funded as a University of Excellence for seven years and, thanks to the measures realised with this support, we have managed to join the ranks of Germany's top universities. For example, we have used that funding to attract top national and international scientists to TU Dresden, optimise our structures and processes, and intensify cooperations with non-university research institutions within the DRESDEN-concept alliance. Our new strategy for the coming years until 2028 was based on these achievements and convinced the reviewers of our merits and potential. I would like to thank everyone involved in the preparation of the proposal and in the participation of the on-site assessment!"

Complete press release of the TU Dresden

Rise and shine to science


Get out of your bed - stop pillow fights and do science instead! This was the motto of this years’ Dresden Science Night on 14 June 2019. Between 6 pm and 1 am, the TU Dresden institutes CRTD, B CUBE and BIOTEC welcomed more than 2,000 visitors. Around 200 scientists from 40 research groups presented a family-friendly programme in the CRTD building.

The guests were introduced to the world of molecules, cells and tissues, axolotl, bees, mice and zebrafish. They admired, experimented, listened to a puppet show, various talks and six young science slammers. The CRTD attracted numerous international guests as many of the presentations were offered both, in German and English.

Around 2,500 researchers from universities, non-university research institutions and science-related companies took part in the Dresden Science Night. This year, the TU Dresden was once again the largest contributor to the Science Night with around 350 programme items.

Dresden Science Night © Friederike Braun

Spring Meeting on the fruit fly


The spring meeting of the research group on seasonal temperature acclimation in Drosophila brought together fruit fly experts from six different countries. The main speakers were Prof Thomas Flatt from the University of Lausanne and research group leader Pierre Leopold from the Institute Curie research center, Paris.

Fruit flies (Drosophilidae) can cause considerable agricultural damage, but also serve as scientific model organisms. Although these animals are the subject of intensive research, knowledge about their temperature dependent behaviour is limited. The research group therefore pursues a synergistic and multidisciplinary approach to study the fruit fly response to temperature fluctuations in the laboratory and in the field. These findings will then be transferred to the pest cherry-vinegar fly (Drosophila suzukii), and help to estimate the consequences of global warming for insects.

From BIOTEC, Prof Suzanne Eaton as speaker and Dr Marko Brankatschk are represented in the DFG-funded research group. At the request of the participants at this year's meeting, the format will be continued next year. Overall, the response to this first spring meeting was very positive and manifested itself in new collaborations between the members of the research group and the invited experts.

More about the research project

Keyvisual der Forschergruppe FOR 2682, „Seasonal temperature acclimation in Drosophila

Children’s University - How does an organism form?


Prof. Dr. Stephan Grill, biophysicist at the TU Dresden Biotechnology Center (BIOTEC), and director at the MPI-CBG, opened the summer term of the Dresden Children’s University on April 2, 2019. Around 550 children in the age of 8 to 12 investigated questions like: How does an organism form? Every living being consists of millions of cells - How do all these cells know where to go and what to do? How can cells form organs or for example a hand? Grill vividly explained how cells connect and how they exert forces in order to organise themselves and bring a set of cells and tissues into the right shape. Using the example of a fly, a fish, and a worm, he illustrated the similarity between growing organisms and a piece of modelling clay: in contrast to modelling clay, living organisms can form completely independently. As thank you from the crowd, Stephan received thunderous applause, many questions, and autograph requests.

Prof. Dr. Stephan Grill during his presentation at the children's university © CMCB

How tissues respond to mechanical stress - underlying mechanism of cell viscoelasticity revealed


Epithelial tissues like our skin are made of cells that are tightly connected through E-Cadherin – a protein that binds adjacent cells together. These tissues respond differently to forces from the environment. When they are subjected to forces for a short duration they behave like an elastic band, whereas, when subjected to the same force for a longer duration they show viscous behavior like honey. This property of tissues, called viscoelasticity, plays a key role to understand tissue shape changes during embryonic development. Although viscoelasticity is a well-known property, the molecular mechanisms underlying such viscoelastic behavior of developing tissues were largely unknown, so far.

The research team around Prof. Dr. Suzanne Eaton from the Biotechnology Center of TU Dresden (BIOTEC), which also operates at Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) and the neighboring Center for Systems Biology Dresden (CSBD), has now identified a key molecular driver governing this process. Together with Frank Jülicher from the CSBD, and the Max Planck Institute for the Physics of Complex Systems (MPI-PKS), the team studied the viscoelastic properties of the epithelial tissues in the Drosophila wing.

The scientists found that E-Cadherin is dynamically turned over between the cell membrane and the cytoplasm when tissues are subjected to mechanical forces. In their recent publication in Current Biology, the researchers reveal that this turnover is achieved by mechanically reducing the binding of an E-Cadherin associated protein called p120-Catenin. Removing the E-Cadherin binding protein from cell junctions speeds up the remodeling of the junctional network, and eventually decreases the cell’s viscoelasticity. The results of this study imply that the dynamic turnover of the E-Cadherin protein is responsible for the viscoelastic behavior of epithelial tissues.

Venkatesan K. Iyer, first author of the publication, says: “The findings in this study provide new perspectives to study developmental processes. Particularly, the in-vivo methods and approaches described in this work could be a starting point for exciting new research aiming at unravelling the interplay between tissue material properties and cell biological processes during embryonic development.”

Original Publication: K. V. Iyer, R. Piscitello-Gómez, J. Paijmans, F. Jülicher, S. Eaton. Epithelial Viscoelasticity Is Regulated by Mechanosensitive E-cadherin Turnover. Current Biology, 2019

© Eaton / MPI-CBG

Optical tweezers measure microscopically small droplets of protein condensates


The research group of Dr. Elisabeth Fischer-Friedrich (CMCB, BIOTEC) developed together with scientists from the Max Planck Institutes of Molecular Cell Biology and Genetics (MPI-CBG) as well as for the Physics of Complex Systems (MPI-PKS) a new technique to measure the material properties of small droplets of protein condensates using optical tweezers. Protein-rich condensates form tiny droplets in different compositions in cells. It has been hypothesized that cells use these droplets as membrane-free organelles to compartmentalize its interior into distinct units of different biochemical characteristics.

"Shape stability and internal molecular dynamics of protein condensates can be characterized by their material properties. However, due to the small size of condensate droplets, established methods to measure material properties are ill-suited. With the aid of optical tweezers, we could now measure the rheology of protein condensates in dependence of salt concentration. Furthermore, our work shows that the surface tension of these protein condensates is many orders of magnitude lower than traditional "oil-in-water" phases. Both, condensate viscosity and surface tension depend sensitively on the concentration of salt ions corroborating the idea that protein interactions rely on electrostatic interactions", says Dr. Elisabeth Fischer-Friedrich.

Read the complete article here.


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