Governing Factors for Active Transport in the Actin Cytoskeleton

Active transport driven by molecular motors in the cytoskeleton is of great importance for various cellular processes, such as secretion of molecules and endocytosis. Thus, the active transport phenomena have been studied in several previous models. However, those models have critical limitations in many aspects. In this study, we employed an agent-based computational model that overcomes the limitations of the previous models, in order to investigate how diverse properties of the actin cytoskeleton affect characteristics and efficiency of the active transport. We found that force dependence of walking velocity of motors that has been neglected in many models plays a very significant role in the active transport. Mobility of motors is lower if an actin network is more elastic because motors are stalled easily at cross-linking points between actin filaments in such an elastic network. We also found that bias in orientation of actin filaments critically regulates motions of motors. In addition, we uncovered how the amount and properties of motors affect movements of motors. Our findings provide new insights into mechanisms by which cells regulate motions of motors in the actin cytoskeleton for the active transport.