Cells exhibit propagating membrane waves which involve the actin cytoskeleton. One type of such membranal waves are Circular Dorsal Ruffles (CDR) which are related to endocytosis and receptor internalization. Experimentally, CDRs have been associated with membrane bound activators of actin polymerization of concave shape. We present experimental evidence for the localization of convex membrane proteins in these structures, and their insensitivity to inhibition of myosin II contractility in immortalized mouse embryo fibroblasts cell cultures. These observations lead us to propose a theoretical model which explains the formation of these waves due to the interplay between complexes that contain activators of actin polymerization and membrane-bound curved proteins of both types of curvature (concave and convex). Our model predicts that the activity of both types of curved proteins is essential for sustaining propagating waves, which are abolished when one type of curved activator is removed. Within this model waves are initiated when the level of actin polymerization induced by the curved activators is higher than some threshold value, which allows the cell to control CDR formation. We demonstrate that the model can explain many features of CDRs, and give several testable predictions. This work demonstrates the importance of curved membrane proteins in organizing the actin cytoskeleton and cell shape.
Propagating Cell-Membrane Waves Driven by Curved Activators of Actin Polymerization
Barak Peleg,Andrea Disanza,G. Scita,N. Gov
Published 2011 in PLoS ONE
ABSTRACT
PUBLICATION RECORD
- Publication year
2011
- Venue
PLoS ONE
- Publication date
2011-04-21
- Fields of study
Biology, Medicine, Physics
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- actin polymerization
Assembly of actin filaments that drives the growth and propagation of membrane waves in the model.
Aliases: actin assembly
- circular dorsal ruffles
Circular actin-rich membrane ruffles on the dorsal cell surface that serve as the wave structures analyzed in the experiments and model.
Aliases: CDRs
- concave membrane proteins
The subset of curved membrane proteins with concave curvature that are treated as actin-polymerization activators in the proposed model.
Aliases: concave curved proteins
- convex membrane proteins
The subset of curved membrane proteins with convex curvature discussed as being present in circular dorsal ruffles.
Aliases: convex curved proteins
- curved membrane proteins
Membrane-bound proteins with intrinsic curvature that are incorporated into the proposed mechanism for organizing ruffle dynamics.
Aliases: curved activators, curved proteins
- myosin ii contractility
The force-generating contractile activity of myosin II tested for its influence on circular dorsal ruffle formation.
Aliases: myosin II-mediated contractility
- propagating membrane waves
Traveling membrane deformations whose dynamics are used as the broader phenomenon underlying circular dorsal ruffles in the abstract.
Aliases: membrane waves
- theoretical model
A proposed mechanistic framework coupling actin-polymerization activators with curved membrane proteins to account for circular dorsal ruffle dynamics.
Aliases: model
REFERENCES
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