AbstractThe regulation of cell fate decisions, morphogenesis, and responses to injury are intimately linked to the process of Fn1 fibrillogenesis. Live imaging and super-resolution microscopy revealed that Fn1 fibrils are not continuous. Instead, Fn1 fibrils arise from nanodomains containing multiple Fn1 dimers. As they move toward cell center, Fn1 nanodomains become organized into linear arrays with a spacing of 130 nm between the nanodomains, with little Fn1 in between; Fn1 nanodomain arrays are resistant to deoxycholate treatment demonstrating that these beaded assemblies are indeed mature Fn1 fibrils. FUD, a bacterial peptide that disrupts Fn1 fibrillogenesis, does not disrupt nanodomain formation; instead, it interferes with the organization of nanodomains into arrays. The nanodomain composition of Fn1 fibrils is observed in multiple contexts: in three-dimensional ECM in vivo, on substrata of different composition and stiffness, and is retained in the absence of cells. The modular architecture of Fn1 fibrils bears important implications for mechanisms of ECM remodeling and signal transduction.
Small-Molecule Labeling of Live Cell Surfaces for Three-Dimensional Super-Resolution Microscopy
