PT  - JOURNAL ARTICLE
AU  - Stéphane Vassilopoulos
AU  - Solène Gibaud
AU  - Angélique Jimenez
AU  - Ghislaine Caillol
AU  - Christophe Leterrier
TI  - Ultrastructure of the axonal periodic scaffold reveals a braid-like organization of actin rings
AID  - 10.1101/636217
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 636217
4099  - http://biorxiv.org/content/early/2019/05/27/636217.short
4100  - http://biorxiv.org/content/early/2019/05/27/636217.full
AB  - Recent super-resolution microscopy studies have unveiled a periodic scaffold of actin rings regularly spaced by spectrins under the plasma membrane of axons. However, ultrastructural details are unknown, limiting a molecular and mechanistic understanding of these enigmatic structures. Here, we combine platinum-replica electron and optical super-resolution micros-copy to investigate the cortical cytoskeleton of axons at the ultrastructural level. We resolve actin rings as braids made of two long, intertwined actin filaments connected by a dense mesh of aligned spectrins. This molecular arrangement contrasts with the currently assumed model of actin rings made of short, capped actin filaments. We propose that braided rings explain the stability of the actin-spectrin scaffold and ultimately help preserving the axon integrity.