Molecular mechanism of dynein-dynactin complex assembly by LIS1

Abstract

Cytoplasmic dynein is a microtubule motor vital for cellular organization and division. It functions as a ~4-megadalton complex containing its cofactor dynactin and a cargo-specific coiled-coil adaptor. However, how dynein and dynactin recognize diverse adaptors, how they interact with each other during complex formation, and the role of critical regulators such as lissencephaly-1 (LIS1) protein (LIS1) remain unclear. In this study, we determined the cryo–electron microscopy structure of dynein-dynactin on microtubules with LIS1 and the lysosomal adaptor JIP3. This structure reveals the molecular basis of interactions occurring during dynein activation. We show how JIP3 activates dynein despite its atypical architecture. Unexpectedly, LIS1 binds dynactin’s p150 subunit, tethering it along the length of dynein. Our data suggest that LIS1 and p150 constrain dynein-dynactin to ensure efficient complex formation.

Cryo-EM Reveals the Mechanochemical Cycle of Reactive Full-length Human Dynein-1

“…High-resolution structural determination of MT-bound dynein has been a challenge in the field. To address this, we recently developed a micrograph-based MT-signal subtraction method (71, 72) , leading to the successful reconstruction of OAD-MT and DDA-MT structures (15, 69, 70) . To capture complete MT-bound dynein-1 structures, we reconstituted full-length dynein-1 on microtubules in apo, ADP, and AMPPNP conditions, all of which increase dynein affinity for MTs (73) (Figure 1B, S2, Table S6) .…”

“…A recent structure of the DDA-LIS1 complex bound to MTs in the presence of AMPPNP revealed a pre-powerstroke state motor domain bound to LIS1 (70) . In this motor-LIS1 complex with a bent linker, the AAA1 pocket binds ADP with a closed conformation, which is speculated to be induced by LIS1 (70) . By contrast, our data demonstrates that this motor state (state-2), without LIS1 binding, can be directly observed under ATP, ADP, AMPPNP, and even apo conditions in the absence of LIS1 (Figure S4) , indicating that this is an intrinsic property of the dynein motor domain.…”

“…Our findings also show that a specific nucleotide environment influences the conformational distribution of the motor domain for full-length dynein. A recent structure of the DDA-LIS1 complex bound to MTs in the presence of AMPPNP revealed a pre-powerstroke state motor domain bound to LIS1 (70) . In this motor-LIS1 complex with a bent linker, the AAA1 pocket binds ADP with a closed conformation, which is speculated to be induced by LIS1 (70) .…”

“…Previous studies have elucidated the structures of truncated dynein (42, 44–47) full-length “phi” dynein-1 (10) (similar to the Greek letter “Φ” (67) ), phi dynein-2 (68) , outer-arm dynein (OAD)-MT (69) , and the DDA-MT (15, 70) complex, each captured under specific nucleotide conditions. Due to either limited resolution, or the loss of structural dynamics that is inherent to these conventional approaches, these structures provide valuable but limited insights into the atomic-level details of the mechanochemical cycle of full-length dynein.…”