Link to Pubmed [PMID] – 23023225
Nat. Cell Biol. 2012 Oct;14(10):1057-67
Integrins in focal adhesions (FAs) mediate adhesion and force transmission to extracellular matrices essential for cell motility, proliferation and differentiation. Different fibronectin-binding integrins, simultaneously present in FAs, perform distinct functions. Yet, how integrin dynamics control biochemical and biomechanical processes in FAs is still elusive. Using single-protein tracking and super-resolution imaging we revealed the dynamic nano-organizations of integrins and talin inside FAs. Integrins reside in FAs through free-diffusion and immobilization cycles. Integrin activation promotes immobilization, stabilized in FAs by simultaneous connection to fibronectin and actin-binding proteins. Talin is recruited in FAs directly from the cytosol without membrane free-diffusion, restricting integrin immobilization to FAs. Immobilized β3-integrins are enriched and stationary within FAs, whereas immobilized β1-integrins are less enriched and exhibit rearward movements. Talin is enriched and mainly stationary, but also exhibited rearward movements in FAs, consistent with stable connections with both β-integrins. Thus, differential transmission of actin motion to fibronectin occurs through specific integrins within FAs.