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Monday, 11 March, 2019

Force for activation


Schematic of the focal adhesion kinase. Figure: M. Bauer (LMU)

Schematic of the focal adhesion kinase. Figure: M. Bauer (LMU)

Tumor invasion and metastasis are major problems in the therapy of cancer patients. NIM scientists around Prof. Hermann Gaub and collaboration partners in Madrid and Heidelberg now elucidated the activation conditions for a key enzyme in this process – a step forward in the development of new therapeutic strategies.

To develop strategies of active tumor metastasis prevention, clarification of the underlying activation process is necessary. Focal adhesion kinase (FAK) is one key enzyme involved in the signaling cascade of cancer invasion and metastasis. This makes it a promising target for cancer therapeutics.

NIM scientists in the lab of Professor Opens external link in new windowHermann Gaub and collaboration partners at the Spanish National Cancer Research Centre in Madrid around Professor Opens external link in new windowDaniel Lietha and at the Heidelberg  Institute for Theoretical Studies around Professor Opens external link in new windowFrauke Gräter now elucidated the force-mediated activation process of FAK and present their results in the journal Opens external link in new windowProceedings of the National Academy of Sciences of the Unites States of America.

What’s the trigger?

As signaling protein, FAK regulates the essential processes of a cell: adhesion, migration and survival. These kinase proteins are localized at the cytoplasmic site of focal adhesion complexes, figuratively the feet of the cells.
“In the non-active state, the focal adhesion kinase is auto-inhibited and inactive with the active center hidden by a protein lid,” explains Opens external link in new windowMagnus Bauer, first author of the publication and NIM-GP graduate student. “Our aim was to examine whether mechanical force can open that lid and thereby trigger activation of this key player by inducing conformational changes.”

This is of special interest as in pathological situations, activated FAK also promotes adhesion to tumor tissue and the extracellular matrix – required for tumor cell invasion and spreading of metastases. In addition, its overexpression in cancer cells results in the inhibition of natural cell death and downregulation of the tumor suppressor gene p53.

Strong attachment

The mechano-environment of a cell influences its behavior. The focal adhesion kinase acts as sensor for changes in the extracellular und intracellular framework. “In single-molecule atomic force microscopy experiments and steered molecular dynamics simulations we could show a force-mediated opening of the auto-inhibitory complex of FAK and consequently the activation of the kinase,” describes the physicist Bauer the experimental approach in Munich.
The Molecular Biomechanics group at HITS has simulated this process on high performance computers to obtain a fully dynamic view of these events. „We successfully uncovered key steps in FAK activation in great detail,” says group leader Frauke Gräter. “We could show that this signaling protein not only gets activated by force but also stays active while being further stretched out.”
In cells, the mechano-activation of FAK is triggered upon stress between the cytoskeleton and the extracellular matrix. “With FAK it seems we found the first non-muscle enzyme to be directly activated by mechanical force,” highlights Bauer. “Transferring our data into cellular systems, we assume that translation of physiological forces into the biochemical signals could be one way to trigger the migration of cancer cells.” This fundamental insight into the mechanisms of this key enzyme for cancer development opens new routes for future tumor therapy strategies. (IA)



Structural and mechanistic insights into mechanoactivation of Focal Adhesion Kinase. Bauer MS, Baumann F, Daday C, Redondo P, Durner E, Jobst MA, Milles LF, Mercadante D, Pippig DA, Gaub HE, Gräter F, Lietha D. PNAS published ahead of print March 15, 2019, Opens external link in new windowdoi:10.1073/pnas.1820567116


Prof. Dr. Hermann Gaub
Biophysics and Molecular Materials
Amalienstraße 54
80799 Munich

Phone: +49 (0)89 - 2180 3172

E-Mail: Opens window for sending emailgaub(at)physik.uni-muenchen.de

Web: Opens external link in new windowwww.biophysik.physik.uni-muenchen.de/index.html

Daniel Lietha, PhD
Cell Signaling and Adhesion Group
Structural and Chemical Biology
Biological Research Center (CIB-CSIC)
Calle Ramiro de Maeztu 9
28040 Madrid

Phone: +34 (0)91 837 3112

E-Mail: Opens window for sending emaildaniel.lietha(at)cib.csic.es

Web: Opens external link in new windowcib.csic.es/research/structural-and-chemical-biology/cell-signalling-and-adhesion

Prof. Dr. Frauke Gräter
Molecular Biomechanics
Heidelberg Institute for Theoretical Studies
Interdisciplinary Center for Scientific Computing, Heidelberg University
Schloss-Wolfsbrunnenweg 35
69118 Heidelberg

Phone: +49 (0)6221 - 533 267

E-Mail: Opens window for sending emailfrauke.graeter(at)h-its.org

Web: Opens external link in new windowwww.h-its.org/de/forschung/mbm/


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