Dynarrestin is a aminothiazole inhibitor of cytoplasmic dyneins 1 and 2. Dynarrestin rapidly and reversibly inhibits dynein 1-driven microtubule gliding in vitro plus a range of dynein 1- and 2-dependent processes in cells without affecting ATP hydrolysis and interfering with ciliogenesis. Dynarrestin suppresses hedgehog (Hh)-dependent proliferation of neuronal precursors and tumor cells.