Mechanical activation of vinculin binding to talin locks talin in an unfolded conformation.
The force-dependent interaction between talin and vinculin plays a crucial role in the initiation and growth of focal adhesions. Here we use magnetic tweezers to characterise the mechano-sensitive compact N-terminal region of the talin rod, and show that the three helical bundles R1-R3 in this region unfold in three distinct steps consistent with the domains unfolding independently. Mechanical stretching of talin R1-R3 enhances its binding to vinculin and vinculin binding inhibits talin refolding after force is released. Mutations that stabilize R3 identify it as the initial mechano-sensing domain in talin, unfolding at ∼5 pN, suggesting that 5 pN is the force threshold for vinculin binding and adhesion progression.
1] Mechanobiology Institute, National University of Singapore, 117411, Singapore [2].
Mingxi
M
Yao
1] Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester, LE1 9HN, UK [2].
Benjamin T
BT
Goult
1] Mechanobiology Institute, National University of Singapore, 117411, Singapore [2] Department of Physics, Xiamen University, Xiamen, Fujian, 361005, China.
Hu
H
Chen
1] Mechanobiology Institute, National University of Singapore, 117411, Singapore [2] Singapore-MIT Alliance for Research and Technology, National University of Singapore, 117543, Singapore.
Peiwen
P
Cong
1] Mechanobiology Institute, National University of Singapore, 117411, Singapore [2] Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Michael P
MP
Sheetz
1] Mechanobiology Institute, National University of Singapore, 117411, Singapore [2] Department of Physics, National University of Singapore, 117542, Singapore [3] Centre for Bioimaging Sciences, National University of Singapore, 117546, Singapore.
Jie
J
Yan
D001665:Binding Sites; D022001:Focal Adhesions / Q000378:metabolism; D008280:Magnetics; D055595:Mechanical Phenomena; D008968:Molecular Conformation; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D013314:Stress, Mechanical; D020349:Surface Plasmon Resonance; D016608:Talin / Q000378:metabolism*; D016596:Vinculin / Q000378:metabolism*
D016608:Talin; D016596:Vinculin