Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 105, Issue 36, Pages 13385-13390Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0805034105
Keywords
atomic force microscopy; force-probe molecular dynamics simulation; muscle signaling; protein kinase regulation; single-molecular force spectroscopy
Categories
Funding
- Deutsche Forschungsgemeinschaft
- Boehringer Ingelheim Fonds
- European Union
- Center for Integrated Protein Science Munich
- Medical Research Council of the United Kingdom
- Medical Research Council [G0600251] Funding Source: researchfish
- MRC [G0600251] Funding Source: UKRI
Ask authors/readers for more resources
Biological responses to mechanical stress require strain-sensing molecules, whose mechanically induced conformational changes are relayed to signaling cascades mediating changes in cell and tissue properties. In vertebrate muscle, the giant elastic protein titin is involved in strain sensing via its C-terminal kinase domain (TK) at the sarcomeric M-band and contributes to the adaptation of muscle in response to changes in mechanical strain. TK is regulated in a unique dual autoinhibition mechanism by a C-terminal regulatory tail, blocking the ATIP binding site, and tyrosine autoinhibition of the catalytic base. For access to the ATP binding site and phosphorylation of the autoinhibitory tyrosine, the C-terminal autoinhibitory tail needs to be removed. Here, we use AFM-based single-molecule force spectroscopy, molecular dynamics simulations, and enzymatics to study the conformational changes during strain-induced activation of human TK. We show that mechanical strain activates ATP binding before unfolding of the structural titin domains, and that TK can thus act as a biological force sensor. Furthermore, we identify the steps in which the autoinhibition of TK is mechanically relieved at low forces, leading to binding of the cosubstrate ATP and priming the enzyme for subsequent autophosphorylation and substrate turnover.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available