Structure and assembly of vimentin intermediate filaments

Date

Nov 29, 2022

Time

4:00 PM - 5:00 PM

Speaker

Cecile Leduc

Affiliation

Institut Jacques Monod, Paris, France

Language

en

Main Topic

Biologie

Host

Stefan Diez

Description

Intermediate filaments (IF) are involved in key cellular functions including polarization, migration, and protection against large deformations. These functions are related to their remarkable ability to extend without breaking, a capacity that should be determined by the molecular organization of subunits within filaments. However, this structure-mechanics relationship remains poorly understood at the molecular level. In the first part of the talk I will present how we showed that vimentin filaments exhibit a ~49 nm axial repeat both in cells and in vitro using super-resolution microscopy (SRM). As unit-length-filaments (ULFs) precursors, which are the building blocks for filament elongation, were measured at ~59 nm, this demonstrates a partial overlap of ULFs during filament assembly. Using an SRM-compatible stretching device, we also provide evidence that the extensibility of vimentin is due to the unfolding of its subunits and not to their sliding, thus establishing a direct link between the structural organization and its mechanical properties (1). In the second part of the talk, I will present how we uncovered the contribution of filament spontaneous fragmentation in the assembly dynamics of type III vimentin IF using a combination of in vitro reconstitution probed by fluorescence imaging and theoretical modeling (2).

Last modified: Nov 30, 2022, 7:38:52 AM