Many nutrients pass from the blood through cell membrane channels into the body cells. However, appropriate channels do not exist for all nutrients.
For example, iron binds outside the cell to a large transport molecule and is imported by other means, via endocytosis, into the cell. The cargo-containing transport molecules bind to the cell membrane, which invaginates inward. The iron molecules along with their transporters are taken up in a small membrane bubble (vesicle) into the cell and released there.
An important ‘wire-puller’ of endocytosis is the protein molecule dynamin. And that in the most literal sense of the word: If a vesicle forms, the dynamin molecules self-assemble and form a spiral around the neck of the vesicle. Dynamin functions like a small motor: It uses the energy of the cell’s GTP to pull the spiral together, constricting the neck of the vesicle so that it detaches from the cell membrane.
The molecular details of this ‘pull’ mechanism around the vesicle neck were previously unknown. In their present study, MDC structural biologists Professor Daumke and Dr. Fälber, together with the endocytosis researcher Professor Volker Haucke and the bioinformatician Dr. Frank Noé of FU Berlin, provide fundamental insights into this process. Using X-ray diffraction analysis, they succeeded in building a structural model of dynamin. For this study it was necessary to produce protein crystals of dynamin. To achieve this, the researchers utilized the insights gained in their previous study about a dynamin-related protein. From the X-ray diffraction pattern of these crystals the researchers were then able to derive a detailed picture of dynamin. “Now that we have an idea of how the dynamin molecule is structured, we can understand at the atomic level how the molecular motor dynamin functions,” said Professor Daumke.
In addition to nutrient uptake, endocytosis is also essential for the transmission of signals between neighboring nerve cells and for the immune system. In this way, for example, macrophages engulf pathogens and make them harmless. Professor Daumke: “However, pathogens like HIV and influenza viruses utilize endocytosis to enter our body cells and to spread there. That is why it is important to gain an even more detailed understanding of the molecular ‘pull’ mechanism of dynamin during endocytosis. Then we can find potential approaches for medical applications – especially for patients with muscle and nerve disorders associated with mutations in the dynamin gene.” In future research projects funded by the German Research Foundation within the framework of the Collaborative Research Centers (SFB740 and SFB958), the MDC researchers intend to take an even closer look at dynamin. They want to find out what structural changes dynamin accomplishes when the cell’s energy carrier GTP binds to the protein and the ‘pull’ mechanism is set in motion at the vesicle neck.
#These authors contributed equally to this work.Barbara Bachtler
Barbara Bachtler | Max-Delbrück-Centrum
Make way for the mini flying machines
21.03.2018 | American Chemical Society
New 4-D printer could reshape the world we live in
21.03.2018 | American Chemical Society
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Physics and Astronomy
21.03.2018 | Materials Sciences
21.03.2018 | Life Sciences