RT Journal Article
SR Electronic
T1 Ultrastructure of the axonal periodic scaffold reveals a braid-like organization of actin rings
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 636217
DO 10.1101/636217
A1 Vassilopoulos, Stéphane
A1 Gibaud, Solène
A1 Jimenez, Angélique
A1 Caillol, Ghislaine
A1 Leterrier, Christophe
YR 2019
UL http://biorxiv.org/content/early/2019/05/13/636217.abstract
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.