Biology subjects

Geohring, I. C.

Publications and source records attributed to Geohring, I. C..

2 recordsLinked to original sources

bioRxiv2024

A nucleotide code governs Lis1's ability to relieve dynein autoinhibition

Dynein-1 is a microtubule motor responsible for the transport of cytoplasmic cargoes. Activation of motility requires it first overcome an autoinhibited state prior to its assembly with dynactin and a cargo adaptor. Studies suggest that Lis1 may relieve dyneins autoinhibited state. However, evidence for this mechanism is lacking. We first set out to determine the rules governing dynein-Lis1 binding, which reveals that their binding affinity is regulated by the nucleotide-bound states of each of three nucleotide-binding pockets within the dynein motor domain. We also find that distinct nucleotide codes coordinate dynein-Lis1 binding stoichiometry by impacting binding affinity at two different sites within the dynein motor domain. Electron microscopy reveals that a 1 Lis1:1 dynein complex directly promotes an open, uninhibited conformational state of dynein, whereas a 2:1 complex resembles the autoinhibited state. Cryo-EM analysis reveals the structural basis for Lis1 opening dynein relies on interactions with the linker domain.

biochemistry↗

bioRxiv2024

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

Dynein-driven cargo transport plays pivotal roles in diverse cellular activities, central to which is dyneins mechanochemical cycle. Here, we performed a systematic cryo-electron microscopic investigation of the conformational landscape of full-length human dynein-1 in reaction, under various nucleotide conditions, on and off microtubules. Our approach reveals over 40 high-resolution structures, categorized into eight states, providing a dynamic and comprehensive view of dynein throughout its mechanochemical cycle. The novel intermediate states reveal important mechanistic insights into dynein function, including a backdoor phosphate release model that coordinates linker straightening, how microtubule binding enhances ATPase activity through a two-way communication mechanism, and the crosstalk mechanism between AAA1 and the regulatory AAA3 site. Our findings also lead to a substantially revised model for the force-generating powerstroke and reveal a means by which dynein exhibits unidirectional stepping. These results substantially improve our understanding of dynein and provide a more complete model of its mechanochemical cycle.

biochemistry↗