Active fluctuations of cytoplasmic actomyosin networks facilitate dynein-driven intracellular transport along microtubules

Inside cells, molecular motors transport cargoes within the actively fluctuating environment known as the cytoplasm. How fluctuations in the cytoplasm affect motor-driven transport is not fully understood. In this study, we investigated the role of fluctuations for transport along microtubules using C. elegans early embryos, focusing on transport driven by cytoplasmic dynein. An artificial motor-cargo complex showed faster transport in vivo than in vitro, suggesting an in vivo acceleration mechanism. We also found that endogenous early endosome transport by dynein is significantly enhanced by the fluctuations in the cytoplasm, which is attributed to the activity of actomyosin networks. An in vitro force measurement of dynein suggests that the asymmetric force response would play a key role in the acceleration. This study provides insights into a regulatory mechanism of molecular motors within actively fluctuating cytoplasm, potentially utilizing random force originating from fluctuating dynamics in the cytoplasm to increase transport efficiency.