title: Emergent properties of composite semiflexible biopolymer networks.
abstract: The semiflexible polymers filamentous actin (F-actin) and intermediate filaments (IF) both form complex networks within the cell, and together are key determinants of cellular stiffness. While the mechanics of F-actin networks together with stiff microtubules have been characterized, the interplay between F-actin and IF networks is largely unknown, necessitating the study of composite networks using mixtures of semiflexible biopolymers. We employ bulk rheology in a simplified in vitro system to uncover the fundamental mechanical interactions between networks of the 2 semiflexible polymers, F-actin and vimentin IF. Surprisingly, co-polymerization of actin and vimentin can produce composite networks either stronger or weaker than pure F-actin networks. We show that this effect occurs through steric constraints imposed by IF on F-actin during network formation and filament crosslinking, highlighting novel emergent behavior in composite semiflexible networks.
authors.affiliation: a School of Engineering and Applied Sciences ; Harvard University ; Cambridge , Massachusetts USA.
authors.forename: Mikkel H
authors.initials: MH
authors.lastname: Jensen
authors.forename: Eliza J
authors.initials: EJ
authors.lastname: Morris
authors.forename: Robert D
authors.initials: RD
authors.lastname: Goldman
authors.forename: David A
authors.initials: DA
authors.lastname: Weitz
mesh_terms: D000199:Actins / Q000378:metabolism*; D001704:Biopolymers / Q000378:metabolism*; D007382:Intermediate Filaments; D012212:Rheology; D014746:Vimentin / Q000378:metabolism*
chemical_list: D000199:Actins; D001704:Biopolymers; D014746:Vimentin
keywords: F-actin, filamentous actin; G-actin, globular (monomeric) actin; IF, intermediate filament; actin; composite; intermediate filaments; model systems; networks; rheology; semiflexible polymers; vimentin