Lis1 Has Two Opposing Modes of Regulating Cytoplasmic Dynein

Regulation is central to the functional versatility of cytoplasmic dynein, a motor involved in intracellular transport, cell division, and neurodevelopment. Previous work established that Lis1, a conserved regulator of dynein, binds to its motor domain and induces a tight microtubule-binding state in dynein. The work we present here—a combination of biochemistry, single-molecule assays, and cryoelectron microscopy—led to the surprising discovery that Lis1 has two opposing modes of regulating dynein, being capable of inducing both low and high affinity for the microtubule. We show that these opposing modes depend on the stoichiometry of Lis1 binding to dynein and that this stoichiometry is regulated by the nucleotide state of dynein’s AAA3 domain. The low-affinity state requires Lis1 to also bind to dynein at a novel conserved site, mutation of which disrupts Lis1’s function in vivo. We propose a new model for the regulation of dynein by Lis1. [Display omitted] •Lis1 has two modes of regulating dynein, set by the nucleotide state of AAA3•Lis1 can induce either tight or weak microtubule-binding states in dynein•The states are set by the number (one or two) of Lis1 β-propellers bound to dynein•The binding site for the second β-propeller is required for Lis1’s function in vivo The lissencephaly protein Lis1 can induce dynein to bind to microtubules either weakly or tightly; these opposing modes of regulation provide new insight into Lis1’s conflicting cellular roles.