Synthetic cargo adaptors reveal molecular features that enhance dynein activation

Cytoplasmic dynein-1 (dynein) facilitates the microtubule-based retrograde trafficking of all cellular cargo. To become active, dynein binds dynactin and one of many cargo-specific adaptors to form the active transport complex. Despite having similar structures, active transport complexes assembled with different adaptors move with different properties in vitro . To explore how adaptors differentially activate dynein, we engineered a library of synthetic adaptors and characterized their ability to activate dynein using in vitro reconstitution and cell-based trafficking assays. We found that the apparent motility of dynein is highly plastic and tunable by the adaptor sequence and that it is possible to engineer adaptors that outperform endogenous adaptors’ ability to generate highly motile active transport complexes. We also found that different adaptors support distinct trafficking behavior and cargo movement in cells. These findings provide insight into how dynein motility is modulated to meet the unique trafficking requirements of all cellular cargo.