**4. Fluorescence imaging and characterization of network transport, mobility and structure**

A key question regarding the cytoskeleton is how the mechanical force response couples to both network structure as well as the mobility and deformations of the comprising filaments. To address this problem, a range of fluorescence labeling schemes can be incorporated into in vitro networks, and various microscopy methods can be employed to image networks and quantify mobility and structure. This section describes different in vitro labeling and imaging methods as well as key results and parameters that can be obtained with the described methods.
