Polymorphism of Cross-Linked Actin Networks in Giant Vesicles

Actin networks cross-linked by natural linkers [Formula presented]-actinin and filamin are generated in giant vesicles by polymerization through ionophore-mediated influx of [Formula presented]. [Formula presented]-actinin induces the formation of randomly linked networks at 25°C which transform at [Formula presented] into spiderweblike gels or ringlike bundles depending on the vesicle size. Muscle filamin forms ringlike structures under all experimental conditions which can supercoil by subsequent [Formula presented] addition. The polymorphism is rationalized in terms of recent models of bivalent ion coupled semiflexible polyelectrolytes and by considering the topology of the linkers.