Actin and microtubule crosslinkers roles in mobility and co-localization of filaments in a composite cytoskeletal network*

Actin and microtubule filaments make a complex interacting network in the cell. This composite network has an essential role in various cell functions such as cell mobility and cell division. Here, we use fluorescent microscopy, fluctuations, and correlation analysis to explore the effect of the actin and microtubule crosslinkers in the cytoskeletal composite network. We systematically vary the amount of actin and microtubule crosslinkers, biotin–NeutrAvidin and MAP65 respectively, and measure the organization and fluctuation of the filaments. We find that the microtubule crosslinker plays the principle role in the organization of the system, while actin crosslinking tunes the mobility of the filaments. We previously showed that the fluctuations of filaments are related to the mechanics, implying that actin crosslinking controls the mechanical properties of the composite network.