Anne Bernheim

In-vitro actomyosin networks have been studied extensively in order to elucidate the myriad of functional morphologies these networks adopt in living cells. Here we demonstrate that unlike kinesin that walks on top of microtutbules, processive myosin motor clusters are an essential part of the actin network itself. Acting as internal active cross-links and applying local stresses as high as 30pN, myosin II motor clusters are not only embedded in the network, but also take a leading role in dictating its structure and dynamics. This activity is supported by the strong confinement of the motor clusters, which increases their effective processivity. The stresses building-up in these networks lead to complex dynamics and can drive their contraction and rupture, depending on motor concentration and cluster size.