The findings appear in the current edition of the journal PLoS Biology.
"Within our cells, we have communicating compartments called vesicles (a bubble-like membrane structure that stores and transports cellular products)," said Dr. Christopher Peters, assistant professor of biochemistry and molecular biology at BCM and lead author on the study. "These vesicles migrate through the cell, meet other vesicles and fuse. That fusion process is, in part, mediated through SNARE proteins that bring the vesicles together. How this happens has been in question for years."
The classic model for this process has been studied using artificial liposome models created in a lab. Peters and his colleagues knew a more physiological fusion model had to be studied in order to see a more accurate account of exactly what acts on this process. Using purified yeast organelles they were able to see that more factors come into play than had been originally believed.
In the classic model, it was believed SNARE proteins originating from two opposing membranes are somehow activated and separated into single proteins. Accepter SNARE proteins then form, allowing fusion with another vesicle membrane. How this mechanistically happens has been unknown.
"What we found with our physiological model is that a tethering complex (termed HOPS) is interacting with the SNARE proteins, activating them to begin this process. Also, the SNARE proteins do not completely separate into single proteins as first believed. Only one protein is detached, leaving behind the acceptor complex," Peters said. "This new acceptor SNARE-complex incorporates the single SNARE that has separated from another vesicle and the two vesicles are in position to fuse."
Researchers found that when this tethering factor was removed, the SNARE proteins were unstable and there was no fusion.
"This finding deals with one of the most fundamental reactions in a cell, how membranes fuse with each other. It is important to understand how this works, because when these events go wrong, either accelerating or slowing down, then it can affect certain disorders such as tumor formation," Peters said. "By using our physiological yeast fusion model, the impact of these tethering factors on the SNARE topology can be investigated, along with the many other factors that come into play. This was not the case in the artificial liposome models used in the past."
Others who contributed to the study include: Kannan Alpadi, Aditya Kulkarni and Sarita Namjoshi, all with the department of biochemistry at BCM; and Veronique Comte, Monique Reinhardt, Andrea Schmidt and Andreas Mayer, all with the department of biochemistry at the University of Lausanne, Switzerland.
Funding for this study came from the National Institutes of Health and Boehringer Ingelheim.
Graciela Gutierrez | EurekAlert!
Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences
Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences