When two worlds collide: actin dynamics on endomembranes regulates membrane trafficking

Membrane trafficking is an essential aspect of cellular physiology, determining the spatial distribution of macromolecules within a cell in response to conditions such as nutrient availability and cellular stress. Much of this trafficking happens at intracellular membrane delimited vesicles and organelles-here referred to as endomembranes. Actin cytoskeletal dynamics contribute to intracellular force production, including fueling aspects of membrane trafficking on endomembranes. Cellular membrane trafficking and actin dynamics have traditionally been studied as separate specializations. Yet, actin networks interact with membranes and contribute to membrane remodeling, organelle motility, and cargo sorting. Here, we propose a conceptual framework for how actin filament networks participate in endomembrane trafficking and describe examples of each of the putative functions. Furthermore, we describe how aberrant actin-endomembrane interactions contribute to disease states and pose some open questions for the field.