Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nuclear Pores Captured on Film

03.05.2016

Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.

Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly visualized the nuclear pore’s selective barrier, but also its dynamic behavior to resolve a long-standing mystery of how unwanted molecules are prevented from entering the nucleus.


Video imaging by high-speed AFM captures native nuclear pore complexes at work; the inset scale bar is 10 nanometers.

University of Basel

Nuclear pore complexes regulate the transport of molecules

The overall structure of the nuclear pores is generally known. These are not simple holes, but are massive transport hubs that incorporate by the thousands into the nuclear membrane. They have a donut-shaped structure consisting of about thirty different proteins, called nucleoporins, and a central transport channel.

Within the pore, several disordered proteins (FG Nups) form a selectivity barrier or filter. While small molecules can easily pass this barrier, large molecules such as proteins are prevented from entering the nuclear pore. An exception to this are the proteins needed in the cell nucleus, for example, for the repair or replication of genetic material. Their translocation from the cytoplasm to the nucleus is assisted by transport receptors that recognize a specific “address tag” carried by these proteins.

High-speed AFM reveals dynamic processes

“With the high-speed AFM we could for the first time, peer inside native nuclear pore complexes, only forty nanometers in size”, says Lim. “This method is a real game changer. We could see the individual FG Nups and film them in action. This wasn’t possible until now!”

Additionally, Yusuke Sakiyama, the PhD student who performed the experiments, had to grow super-sharp carbon nanofibers on each high-speed probe in order to reach inside the NPC. This then generates a video sequence from multiple images that enables the researcher to observe the “true to life” dynamics of biological processes at the nanometer level.

A barrier of undulating molecular “tentacles”

Due to the high spatial and temporal resolution, the scientists were able to show that the FG Nup filaments are highly flexible. “They are not stiff bristles but quite the contrary. Like the thinnest tentacles, the FG Nups rapidly fluctuate, elongate and retract, and sometimes even briefly intermingle within the pore”, says Lim.

The speed of their motion determines which molecules can pass through the pore. “Large particles move much more slowly than the FG Nups and are thus hindered from entering the NPC by repeated collisions”, explains Lim. “Small molecules, however, undergo rapid diffusion and have a high probability of passing the FG Nup barrier.”

By understanding how NPCs function as transport hubs in living cells, Lim who is a member of the NCCR Molecular Systems Engineering is now investigating how NPC-inspired selective filters might regulate molecular traffic in non-biological systems.

Original source

Yusuke Sakiyama, Adam Mazur, Larisa E. Kapinos and Roderick Y.H. Lim
Spatiotemporal dynamics of the nuclear pore complex transport barrier resolved by high-speed atomic force microscopy
Nature Nanotechnology (2016), doi: 10.1038/nnano.2016.62

Further information

Prof. Dr. Roderick Lim, University of Basel, Biozentrum, and Swiss Nanoscience Institute, phone: +41 61 267 20 83, E-Mail: roderick.lim@unibas.ch

Dr. Katrin Bühler, University of Basel, Biozentrum, Communications, tel. +41 61 267 09 74, email: katrin.buehler@unibas.ch

Weitere Informationen:

http://www.biozentrum.unibas.ch/research/groups-platforms/overview/unit/lim/ - Research group Prof. Roderick Lim
http://dx.doi.org/10.1038/nnano.2016.62 - Abstract

Dr. Katrin Bühler | Universität Basel

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes

17.07.2018 | Life Sciences

Electronic stickers to streamline large-scale 'internet of things'

17.07.2018 | Information Technology

Behavior-influencing policies are critical for mass market success of low carbon vehicles

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>