Mechanically Activated Integrin Switch Controls
5β1 Function
Julie C. Friedland,1,2*
Mark H. Lee,1,2*
David Boettiger1,2,3
The cytoskeleton, integrin-mediated adhesion, and substrate
stiffness control a common set of cell functions required for
development and homeostasis that are often deranged in cancer.
The connection between these mechanical elements and chemical
signaling processes is not known. Here, we show that
5β
1 integrin switches between relaxed and tensioned states in response
to myosin II–generated cytoskeletal force. Force combines
with extracellular matrix stiffness to generate tension that
triggers the integrin switch. This switch directly controls
the
5β
1-fibronectin bond strength through engaging the
synergy site in fibronectin and is required to generate signals
through phosphorylation of focal adhesion kinase. In the context
of tissues, this integrin switch connects cytoskeleton and extracellular
matrix mechanics to adhesion-dependent motility and signaling
pathways.
1 Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
2 Department of Microbiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
3 Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA.
* These authors contributed equally to the work.
To whom correspondence should be addressed: E-mail: boettige{at}upenn.edu