Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How cells stick together tightly

05.11.2019

Dresden researchers uncover self-organization of tight junctions, the glue between cells.

Our organs are specialized compartments, each with its own milieu and function. To seal our organs, the cells in the tissue must form a barrier which is tight even down to the level of molecules. This barrier is formed by a protein complex that “sticks” all the cells together without any gaps.


Formation of the tissue barrier: One of the proteins required to make the tight junction was labeled with a fluorescent dye. Using fluorescence microscopy, the labeled proteins were observed live.

Beutel et al.

The loss of this barrier can lead to many diseases, including the infiltration of pathogens into our internal system. Since maintaining the tissue barrier is central to our organ functions, it is important to understand how this barrier is created between cells.

Researchers at the Max Planck Institute for Molecular Cell Biology and Genetics (MPI-CBG) in Dresden discovered that cells use a process similar to condensation of water droplets on a cold window to form cell junctions.

Specific proteins condense as droplets on the cell membrane when neighboring cells touch. These droplets enrich all the components required to create a stable barrier between cells. The results are published in the journal Cell.

The surface of our organs is lined with a layer of epithelial cells. These cells play an important role in protecting our organs, adapting them to a changing environment, and transporting molecules in and out of tissues. What seals epithelial tissue are tight junctions that act as the molecular barrier between cells.

A key question for scientists was how this molecular complex robustly assembles between cells. The team around MPI-CBG research group leader Alf Honigmann set out to piece together the building blocks that could explain how tight junctions are built.

One key building block of tight junctions is the family of ZO proteins which are located on the inside of cells. Using a combination of tissue imaging, gene editing, and biochemistry, the researchers found that the proteins inherently contain regions that allow them to stick to one another and form droplets on the membrane of epithelial cells. This ability allows the ZO proteins to become more concentrated and to selectively sequester adhesion proteins, needed for tight junction assembly.

Oliver Beutel, the first author of the study, explains: “This process is somewhat similar to the phenomenon of water condensing on a cold glass window, spontaneously forming liquid droplets and streams. In the case of tight junctions, the ZO proteins condense on the inside of epithelial cell membranes to form a hub where all the necessary components can be encapsulated to assemble into a tight junction.” These findings suggest that the properties of ZO proteins can serve as a template to reconstruct the architecture and function of tight junctions.

Alf Honigmann, the supervisor of the study, concludes: “This study reveals an important mechanism, which epithelial cells use to establish tight junctions. Our work on this protein machinery exemplifies the principles how cells leverage simple physical phenomena like condensation to assemble complex molecular structures.” He adds: “Our findings imply exciting possibilities how junctions can quickly remodel during tissue growth and repair.”

Wissenschaftliche Ansprechpartner:

Dr. Alf Honigmann
+49 (0) 351 210 2969
honigmann@mpi-cbg.de

Originalpublikation:

Oliver Beutel, Riccardo Maraspini, Karina Pombo-García, Cécilie Martin-Lemaitre, Alf Honigmann: “Phase Separation of Zonula Occludens Proteins Drives Formation of Tight Junctions” Cell, 31. October, 2019, doi: https://doi.org/10.1016/j.cell.2019.10.011

Katrin Boes | Max-Planck-Institut für molekulare Zellbiologie und Genetik

More articles from Life Sciences:

nachricht Human skin is an important source of ammonia emissions
27.05.2020 | Max-Planck-Institut für Chemie

nachricht Biotechnology: Triggered by light, a novel way to switch on an enzyme
27.05.2020 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

German-British Research project for even more climate protection in the rail industry

28.05.2020 | Transportation and Logistics

A special elemental magic

28.05.2020 | Physics and Astronomy

Skoltech scientists get a sneak peek of a key process in battery 'life'

28.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>