Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Ring- and arc-shaped pores drive stressed cells to a programmed death


Tübingen biochemists use a super-microscope to watch Bax proteins start apoptosis

Damaged cells can commit suicide by a process of apoptosis, or programmed cell death. If this mechanism fails to work properly, the cell can become cancerous. Tübingen researchers in a team headed by professor Ana García-Sáez of the Interfaculty Institute of Biochemistry are helping to explain important steps in the process of apoptosis.

They know from previous studies that apoptosis begins with the activation of what are known as Bax proteins. If a cell is under stress, Bax proteins deposit on the surface of mitochondria in symmetrical pairs. The researchers then observed that the otherwise impermeable shell of the mitochondria becomes permeable – letting through cytochrome c.

Once that happens, the process of cellular death cannot be reversed. But what happened in between was a mystery which for a long time puzzled apoptosis researchers. Now Ana García-Sáez and her team have been able to use a supermicroscope to watch how Bax proteins form pores in the mitochondrial shell, making it permeable. Their study is published in The EMBO Journal.

In healthy cells Bax is present as a soluble, single protein, which moves back and forth between the cytoplasm and the surface of mitochondria. When stress signals set in, Bax proteins accumulate on mitochondria. Scientists had suspected that Bax pairs linked up to form pores, opening the outer shell of the mitochondria for certain substances. But until now, they had not been able to observe if Bax structures could form these pores on the mitochondria. For this reason, the doubt had been cast on the theory.

In collaboration with Jonas Ries at EMBL, Ana García-Sáez and her team used a super-resolution microscope that is able to make out individual molecules. This gave them images showing how Bax proteins gathered on mitochondria of cells under stress in cell-death mode.

The Bax structures they found were of differing shapes and sizes, but could not have been created by chance. They were in the shape of closed rings, incomplete rings, arcs like a sickle moon, and in lines. The formation of these structures of Bax correlated with the mitochondrial shell becoming permeable. This confirms the researchers’ hypothesis - thereby filling a crucial gap in our knowledge of the processes involved in apoptosis.

Raquel Salvador-Gallego, Markus Mund, Katia Cosentino, Jale Schneider, Joseph Unsay, Ulrich Schraermeyer, Johann Engelhardt, Jonas Ries and Ana J García-Sáez: Bax assembly into rings and arcs in apoptotic mitochondria is linked to membrane pores. The EMBO Journal, DOI 10.15252/embj.2015933841

Professor Ana García-Sáez
University of Tübingen
Interfaculty Institute of Biochemistry
Phone +49 7071 29-73318

Dr. Karl Guido Rijkhoek | idw - Informationsdienst Wissenschaft
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>