PT  - JOURNAL ARTICLE
AU  - Darshika Tomer
AU  - Cecilia Arriagada
AU  - Sudipto Munshi
AU  - Brianna E. Alexander
AU  - Brenda French
AU  - Pavan Vedula
AU  - Valentina Caorsi
AU  - Andrew House
AU  - Murat Guvendiren
AU  - Anna Kashina
AU  - Jean E. Schwarzbauer
AU  - Sophie Astrof
TI  - A new mechanism of fibronectin fibril assembly revealed by live imaging and super-resolution microscopy
AID  - 10.1101/2020.09.09.290130
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2020.09.09.290130
4099  - http://biorxiv.org/content/early/2022/04/26/2020.09.09.290130.short
4100  - http://biorxiv.org/content/early/2022/04/26/2020.09.09.290130.full
AB  - Fn1 fibrils have long been viewed as continuous fibers composed of extended, periodically aligned Fn1 molecules. However, our live imaging and single-molecule localization microscopy (SMLM) are inconsistent with this traditional view and show that Fn1 fibrils are composed of roughly spherical nanodomains containing 6-11 Fn1 dimers. As they move toward the cell center, Fn1 nanodomains become organized into linear arrays, wherein nanodomains are spaced at the average periodicity of 105±17 nm. Periodical Fn1 nanodomain arrays are bona fide fibrils: they are resistant to deoxycholate treatment and retain nanodomain periodicity in the absence of cells. The nanodomain periodicity in fibrils remained constant when probed with antibodies recognizing distinct Fn1 epitopes or combinations of antibodies recognizing epitopes spanning the length of Fn1. FUD, a bacterial peptide that binds Fn1 N-terminus and disrupts Fn1 fibrillogenesis does not disrupt the formation of Fn1 nanodomains, instead, it blocks the organization of Fn1 nanodomains into periodical arrays. These studies establish a new paradigm of Fn1 fibrillogenesis.Competing Interest StatementThe authors have declared no competing interest.