Characteristic features of the frequency-dependent viscoelasticity as a function of the relative concentration *R* of wild-type (*circles*) and mutant (*triangles*) *α*-actinin-4. (*A*) The plateau modulus *G′* _{plateau} has comparable values for wild-type and mutant, and increases with cross-linker concentration. Above *R* = 0.005, the plateau modulus follows a power law for both cross-linker types, as indicated by the solid line for the wild-type and the dotted line for the mutant, and their respective slopes (*lower right*). (*B*) The ratio of the plateau modulus and the corresponding viscous modulus, (*G′*/*G″*)_{plateau}, which indicates the solidness of the network, grows weakly with increasing cross-linker concentration, and is on average higher for the mutant than for the wild-type at the same concentration. (*C*) The frequency at which the elastic plateau occurs (minimum in *G″*) increases weakly with cross-linker concentration, and is systematically smaller for the mutant. (*D*) The relaxation frequency of the network (maximum in *G″*) appears to be independent of the cross-linker concentration, and is about an order of magnitude smaller for the mutant.

## PubMed Commons