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Cryo-electron tomography reveals that dynactin recruits a team of dyneins for processive motility.

ABSTRACT: Cytoplasmic dynein is a protein complex that transports molecular cargo along microtubules (MTs), playing a key role in the intracellular trafficking network. Vertebrate dynein's movement becomes strikingly enhanced upon interacting with dynactin and a cargo adaptor such as BicaudalD2. However, the mechanisms responsible for increased transport activity are not well understood, largely owing to limited structural information. We used cryo-electron tomography (cryo-ET) to visualize the 3D structure of the MT-bound dynein-dynactin complex from Mus musculus and show that the dynactin-cargo adaptor complex binds two dimeric dyneins. This configuration imposes spatial and conformational constraints on both dynein dimers, positioning the four motor domains in proximity to one another and oriented toward the MT minus end. We propose that grouping multiple dyneins onto a single dynactin scaffold promotes collective force production, increased processivity, and unidirectional movement, suggesting mechanistic parallels to axonemal dynein. These findings provide structural insights into a previously unknown mechanism for dynein regulation.

SUBMITTER: Grotjahn DA

PROVIDER: S-EPMC5969528 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Cryo-electron tomography reveals that dynactin recruits a team of dyneins for processive motility.

Grotjahn Danielle A DA Chowdhury Saikat S Xu Yiru Y McKenney Richard J RJ Schroer Trina A TA Lander Gabriel C GC

Nature structural & molecular biology 20180207 3

Cytoplasmic dynein is a protein complex that transports molecular cargo along microtubules (MTs), playing a key role in the intracellular trafficking network. Vertebrate dynein's movement becomes strikingly enhanced upon interacting with dynactin and a cargo adaptor such as BicaudalD2. However, the mechanisms responsible for increased transport activity are not well understood, largely owing to limited structural information. We used cryo-electron tomography (cryo-ET) to visualize the 3D structu ...[more]

PMID: 29416113

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Project description:Helicobacter pylori is a bacterial pathogen that can cause many gastrointestinal diseases including ulcers and gastric cancer. A unique chemotaxis-mediated motility is critical for H. pylori to colonize in the human stomach and to establish chronic infection, but the underlying molecular mechanisms are not well understood. Here we employ cryo-electron tomography to reveal detailed structures of the H. pylori cell envelope including the sheathed flagella and chemotaxis arrays. Notably, H. pylori possesses a distinctive periplasmic cage-like structure with 18-fold symmetry. We propose that this structure forms a robust platform for recruiting 18 torque generators, which likely provide the higher torque needed for swimming in high-viscosity environments. We also reveal a series of key flagellar assembly intermediates, providing structural evidence that flagellar assembly is tightly coupled with biogenesis of the membrane sheath. Finally, we determine the structure of putative chemotaxis arrays at the flagellar pole, which have implications for how direction of flagellar rotation is regulated. Together, our pilot cryo-ET studies provide novel structural insights into the unipolar flagella of H. pylori and lay a foundation for a better understanding of the unique motility of this organism.ImportanceHelicobacter pylori is a highly motile bacterial pathogen that colonizes approximately 50% of the world's population. H. pylori can move readily within the viscous mucosal layer of the stomach. It has become increasingly clear that its unique flagella-driven motility is essential for successful gastric colonization and pathogenesis. Here we use advanced imaging techniques to visualize novel in situ structures with unprecedented detail in intact H. pylori cells. Remarkably, H. pylori possesses multiple unipolar flagella, which are driven by one of the largest flagellar motors found in bacteria. These large motors presumably provide higher torque needed by the bacterial pathogens to navigate in viscous environment of the human stomach.

Dataset Information

Cryo-electron tomography reveals that dynactin recruits a team of dyneins for processive motility.

Publications

Cryo-electron tomography reveals that dynactin recruits a team of dyneins for processive motility.

Similar Datasets

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