  The semiflexible F-actin network of the cytoskeleton is cross-linked by a
variety of proteins including filamin, which contain Ig-domains that unfold
under applied tension. We examine a simple semiflexible network model
cross-linked by such unfolding linkers that captures the main mechanical
features of F-actin networks cross-linked by filamin proteins and show that
under sufficiently high strain the network spontaneously self-organizes so that
an appreciable fraction of the filamin cross-linkers are at the threshold of
domain unfolding. We propose an explanation of this organization based on a
mean-field model and suggest a qualitative experimental signature of this type
of network reorganization under applied strain that may be observable in
intracellular microrheology experiments of Crocker et al.
