Load Adaptation of Lamellipodial Actin Networks

Ultrastructure of the actin cytoskeleton

The actin cytoskeleton is the primary force-generating machinery in the cell, which can produce pushing (protrusive) forces using energy of actin polymerization and pulling (contractile) forces via sliding of bipolar filaments of myosin II along actin filaments, as well as perform other key functions. These functions are essential for whole cell migration, cell interaction with the environment, mechanical properties of the cell surface and other key aspects of cell physiology. The actin cytoskeleton is a highly complex and dynamic system of actin filaments organized into various superstructures by multiple accessory proteins. High resolution architecture of functionally distinct actin arrays provides key clues for understanding actin cytoskeleton functions. This review summarizes recent advance in our understanding of the actin cytoskeleton ultrastructure.

Mechanoreciprocity in cell migration

Cell migration is an adaptive process that depends on and responds to physical and molecular triggers. Moving cells sense and respond to tissue mechanics and induce transient or permanent tissue modifications, including extracellular matrix stiffening, compression and deformation, protein unfolding, proteolytic remodelling and jamming transitions. Here we discuss how the bi-directional relationship of cell-tissue interactions (mechanoreciprocity) allows cells to change position and contributes to single-cell and collective movement, structural and molecular tissue organization, and cell fate decisions.

Adaptive Actin Networks

Despite their fundamental importance in the regulation of cell physiology, the mechanisms that confer cell adaptability to changes in the microenvironment are poorly understood. A recent study in Cell (Mueller et al., 2017) examines the capability of branched actin networks to respond and adapt to mechanical load in vivo.