Lis1 binding regulates force-induced detachment of cytoplasmic dynein from microtubules

Cytoplasmic dynein-1 (dynein) is an AAA+ motor that transports intracellular cargos towards the microtubule minus end. Lissencephaly-1 (Lis1) binds to the AAA+ ring and stalk of dyneins motor domain and promotes the assembly of active dynein complexes. Recent studies showed that Lis1 slows motility when it remains bound to dynein, but the underlying mechanism remained unclear. Using single-molecule and optical trapping assays, we investigated how Lis1 binding affects the motility and force generation of yeast dynein in vitro. We showed that Lis1 does not slow dynein motility by serving as a roadblock or tethering dynein to microtubules. Lis1 binding also does not affect the forces that stall dynein movement, but it induces prolonged stalls and reduces the asymmetry in the force-induced detachment of dynein from microtubules. The mutagenesis of the Lis1 binding sites on dyneins stalk partially recovers this asymmetry but does not restore dynein velocity. These results suggest that Lis1s interaction with the AAA+ ring is sufficient to result in slower movement and that Lis1s interaction with dyneins stalk slows force-induced detachment of dynein from microtubules.