Alpha-actinin and filamin cooperatively enhance the stiffness of actin filament networks.
BACKGROUND
The close subcellular proximity of different actin filament crosslinking proteins suggests that these proteins may cooperate to organize F-actin structures to drive complex cellular functions during cell adhesion, motility and division. Here we hypothesize that alpha-actinin and filamin, two major F-actin crosslinking proteins that are both present in the lamella of adherent cells, display synergistic mechanical functions.


RESULTS
Using quantitative rheology, we find that combining alpha-actinin and filamin is much more effective at producing elastic, solid-like actin filament networks than alpha-actinin and filamin separately. Moreover, F-actin networks assembled in the presence of alpha-actinin and filamin strain-harden more readily than networks in the presence of either alpha-actinin or filamin.


CONCLUSIONS
These results suggest that cells combine auxiliary proteins with similar ability to crosslink filaments to generate stiff cytoskeletal structures, which are required for the production of internal propulsive forces for cell migration, and that these proteins do not have redundant mechanical functions.
Esue
Osigwe
O
Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America.
Tseng
Yiider
Y
Wirtz
Denis
D
D008841:Actin Cytoskeleton / Q000737:chemistry* / Q000378:metabolism; D000185:Actinin / Q000737:chemistry* / Q000378:metabolism; D003285:Contractile Proteins / Q000737:chemistry* / Q000378:metabolism; D004548:Elasticity; D064448:Filamins; D007700:Kinetics; D008840:Microfilament Proteins / Q000737:chemistry* / Q000378:metabolism; D012212:Rheology
D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D000185:Actinin