Force interacts with macromolecular structure in activation of TGF-beta.
Article Details
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Dong X, Zhao B, Iacob RE, Zhu J, Koksal AC, Lu C, Engen JR, Springer TA
Force interacts with macromolecular structure in activation of TGF-beta.
Nature. 2017 Feb 2;542(7639):55-59. doi: 10.1038/nature21035. Epub 2017 Jan 25.
- PubMed ID
- 28117447 [ View in PubMed]
- Abstract
Integrins are adhesion receptors that transmit force across the plasma membrane between extracellular ligands and the actin cytoskeleton. In activation of the transforming growth factor-beta1 precursor (pro-TGF-beta1), integrins bind to the prodomain, apply force, and release the TGF-beta growth factor. However, we know little about how integrins bind macromolecular ligands in the extracellular matrix or transmit force to them. Here we show how integrin alphaVbeta6 binds pro-TGF-beta1 in an orientation biologically relevant for force-dependent release of TGF-beta from latency. The conformation of the prodomain integrin-binding motif differs in the presence and absence of integrin binding; differences extend well outside the interface and illustrate how integrins can remodel extracellular matrix. Remodelled residues outside the interface stabilize the integrin-bound conformation, adopt a conformation similar to earlier-evolving family members, and show how macromolecular components outside the binding motif contribute to integrin recognition. Regions in and outside the highly interdigitated interface stabilize a specific integrin/pro-TGF-beta orientation that defines the pathway through these macromolecules which actin-cytoskeleton-generated tensile force takes when applied through the integrin beta-subunit. Simulations of force-dependent activation of TGF-beta demonstrate evolutionary specializations for force application through the TGF-beta prodomain and through the beta- and not alpha-subunit of the integrin.