Heidelberg scientists develop new methods to measure intracellular protein movement
Numerous obstacles posed by cellular structures hinder protein movements within the cell. Researchers from Heidelberg University and the German Cancer Research Center have succeeded in mapping the intracellular topology by observing proteins in living cells on multiple time and length scales.
By developing a new fluorescence microscopy-based technique, the researchers were able to measure how long it takes proteins to move over distances ranging from 0.2 to 3 micrometres in living cells. Under the direction of Dr. Karsten Rippe, the team analysed the data and developed a mathematical model to reconstruct the intracellular structures. The results of their research were published in “Nature Communications”.
Cellular structures such as membranes, the cytoskeleton and the DNA genome form a dynamic three-dimensional maze inside the cell. Proteins have to find their way through it to reach the sites where they are active. Accordingly, the spatial structure of the cell’s interior is a key factor for protein transport and cell function. “Cellular structures have been visualized in many microscopic studies.
But it is still unclear how the diffusing protein in the cell ‘senses’ this internal network of obstacles,” says Dr. Rippe. To address this question, his team devised a method to infer the cellular topology from the random motion of proteins. The team built their own fluorescence spectroscopy system to observe fluorescent proteins. According to Karsten Rippe, the largest obstacles were densely packed areas of DNA in the cell nucleus.
“A protein in a cell moves much like a marble in a labyrinth game, jockeying its way through the maze,” said Michael Baum, the study’s first author, who pursued the research as part of his PhD thesis at Heidelberg University. The marbles move easily over short distances, but then they encounter an obstacle and are slowed down as they move along.
This results in “stop-and-go” travelling with reduced average speed over longer distances. In their analysis of protein movements, the Heidelberg researchers mapped distances and corresponding translocation times needed for this travel, resulting in the average distance between obstacles. A mathematical model based on this data allowed the scientists to describe the measured movement of the proteins in the cell and reconstruct its topology – at a significantly better resolution than currently possible with light microscopy images, as Dr. Rippe points out.
“The obstacle structure encountered by a protein moving through the cell is porous, much like a sponge,” explains the Heidelberg researcher. Larger proteins were occasionally trapped in this dynamic structure for several minutes. Furthermore, drugs used in chemotherapy or to treat malaria were found to affect the mobility of proteins in the nucleus and make the DNA thicket more permeable. Dr. Rippe and his team now plan to apply their new approach in further experiments at the BioQuant Centre of Heidelberg University and the German Cancer Research Center. They will focus on the interrelation between drug-induced changes in the cell structure and protein transport as well as the disease-related deregulation of this process.
Funding for the research was provided by the Federal Ministry of Education and Research.
M. Baum, F. Erdel, M. Wachsmuth & K. Rippe: Retrieving the intracellular topology from multi-scale protein mobility mapping in living cells. Nature Communications 5, 4494 (24 July 2014), doi: 10.1038/ncomms5494
Dr. Karsten Rippe
Phone: +49 6221 54-51376
Communications and Marketing
Phone: +49 6221 542311
Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft
More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Materials Sciences
19.01.2018 | Health and Medicine
19.01.2018 | Physics and Astronomy