Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mechanism to Repair Clumped Proteins Explained

21.11.2012
Heidelberg researchers uncover the function of specific molecular chaperones

Clumped proteins can be dissolved with the aid of cellular repair systems – a process of critical importance for cell survival especially under conditions of stress. Heidelberg researchers have now decrypted the fundamental mechanism for dissolving protein aggregates that involves specific molecular chaperones.


Mechanism of protein aggregate dissolution through Hsp70/Hsp100 cooperation. The ring-shaped Hsp100 has two structural states, one inactive and the other activated. A molecular switch keeps the Hsp100 chaperone in the inactive state. Hsp70 causes the switch to flip, thereby activating the Hsp100 chaperone. In this state it can pull protein strands out of the aggregate. The activation of Hsp100 is not permanent, with the chaperone reverting to the inactive state after the aggregate has dissolved.

Picture credits: ZMBH

Scientists from the Center for Molecular Biology of Heidelberg University and the German Cancer Research Center cooperated with experts from the Heidelberg Institute for Theoretical Studies on the project. The results of the research appeared in two simultaneously published articles in “Nature Structural & Molecular Biology”.

Proteins consist of long chains of successive amino acids and perform vital functions in every cell. To function, every amino acid chain must first assume a specific three-dimensional structure – it has to fold itself. A change in growth conditions, such as an increase in ambient temperature, can cause proteins to lose their structure and unfold. Unfolded protein chains run the risk of clumping, forming protein aggregates. “If such aggregates form, the proteins cannot function, which can lead to cell death, which we see in neurodegenerative diseases such as Alzheimer’s and Parkinson’s, and even in ageing processes”, explains Prof. Dr. Bernd Bukau, Director of the Center for Molecular Biology of Heidelberg University (ZMBH), who is also a researcher at the German Cancer Research Center (DKFZ).

But clumping does not necessarily mean the end of a protein’s life cycle. “Cells have repair systems for damaged proteins, so-called molecular chaperones, that can dissolve even aggregated proteins and refold them”, clarifies Dr. Axel Mogk, also a member of the ZMBH and DKFZ. The repair is carried out by a cooperating team of two chaperones, called Hsp70 and Hsp100. The Heidelberg researchers were able to demonstrate that the activity of the Hsp100 chaperone is regulated by a built-in molecular switch.
This switch is first positioned to curtail energy consumption, i.e. ATP hydrolysis, and thereby the activity of the Hsp100 chaperone. The cooperating Hsp70 protein changes the position of the switch and activates Hsp100 directly at the protein aggregate. In this state, the “motor” of the ring-shaped Hsp100 protein runs at full speed, reaches top performance and is able to extract individual chains from the aggregate. Afterwards, the extracted, unfolded protein can start the folding process over. The results of the Heidelberg research also show that the built-in switch’s control of Hsp100 activity is of vital importance for this complicated protein machine, because the loss of regulation in hyperactive, i.e. permanently activated, Hsp100 protein variants leads to cell death.

The research collaboration falls under the DKFZ-ZMBH Alliance, the strategic cooperation of the German Cancer Research Center and the Center for Molecular Biology of Heidelberg University. The Heidelberg Institute for Theoretical Studies (HITS) develops new theoretical approaches to interpreting the burgeoning amount of experimental data.

Original publications:

F. Seyffer, E. Kummer, Y. Oguchi, J. Winkler, M. Kumar, R. Zahn, V. Sourjik, B. Bukau & A. Mogk: Hsp70 proteins bind Hsp100 regulatory M domains to activate AAA+ disaggregase at aggregate surfaces, Nature Structural & Molecular Biology, 18 November 2012, doi: 10.1038/nsmb.2442

Y. Oguchi, E. Kummer, F. Seyffer, M. Berynskyy, B. Anstett, R. Zahn, R.C. Wade, A. Mogk & B. Bukau: A tightly regulated molecular toggle controls AAA+ disaggregase, Nature Structural & Molecular Biology, 18 November 2012, doi: 10.1038/nsmb.2441

Contact:

Prof. Dr. Bernd Bukau, Dr. Axel Mogk
Center for Molecular Biology of Heidelberg University
Phone: +49 (0)6221 54-6850, direktor@zmbh.uni-heidelberg.de
Phone: +49 (0)6221 54-6863, a.mogk@zmbh.uni-heidelberg.de

Communications and Marketing
Press Office, phone: +49 (0)6221 54-2311
presse@rektorat.uni-heidelberg.de

Marietta Fuhrmann-Koch | idw
Further information:
http://www.uni-heidelberg.de

More articles from Life Sciences:

nachricht Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg

nachricht Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>